November 5, 2024
A Monte Carlo Approach for Simulating Electrical Conductivity in Highly Porous Ceramic Composites: Impact of Internal Structure
Daniel Budáč - ,
Vojtěch Miloš - ,
Michal Carda - ,
Martin Paidar *- ,
Karel Bouzek - , and
Jürgen Fuhrmann
This publication is Open Access under the license indicated. Learn More
Porous ceramic composites play an important role in several applications. This is due to their unique properties resulting from a combination of various materials. Determination of the composite properties and structure is crucial for their further development and optimization. However, composite analysis often requires complex, expensive, and time-demanding experimental work. Mathematical modeling represents an effective tool to substitute experimental approach. The present study employs a Monte Carlo 3D equivalent electronic circuit network model developed to analyze a highly porous composite on the basis of minimum easily obtainable input parameters. Solid oxide cell electrodes were used as a model example, and this study focuses primarily on materials with a porosity of 55% and higher, characterized by deviation of behavior from those of lower void fraction share. This task is approached by adding to the original Monte Carlo model an additional parameter defining the void phase coalescence phenomenon. The enhanced model accurately simulates electrical conductivity for experimental samples of up to 75% porosity. Using sample composition, single-phase properties, and experimentally determined conductivity, this model allows us to estimate data of the internal structure of the material. This approach offers a rapid and cost-effective method to study material microstructure, providing insights into properties, such as electrical conductivity and heat conductivity. The present research thus contributes to advancing predictive capabilities in understanding and optimizing the performance of composite materials with potential in various technological applications.
Plasma Tailoring of NH2-MIL-53 with Enhanced Fluorescence Emission for Simultaneous Detection of Multiple Heavy Metals in Water
Yu Ding - ,
Yuyang Hu - ,
Yangyang Zhao - ,
Yaru Li - ,
Ziteng Huang - ,
Soufian Chakir - ,
Yongfei Xu - ,
Daosheng Sun - ,
Songqin Liu - ,
Huanting Wang - , and
Xianbiao Wang *
Indium, copper, and mercury are important raw materials in the electronics industry and often coexist in factory wastewater. Therefore, the development of a highly sensitive and selective method for the simultaneous detection of these heavy metal ions is of great significance for water quality monitoring and environmental protection. Herein, we report a NH2-MIL-53 fluorescent probe for the simultaneous detection of trace In3+, Cu2+, and Hg2+ in water. After a low-temperature NH3 plasma tailoring treatment for grafting electron-donor amine groups, the obtained NH2-MIL-53-M exhibited enhanced fluorescence emission intensity (∼6 times) coupled with selective adsorption of In3+, Cu2+, and Hg2+. This quenched the NH2-MIL-53-M fluorescence and allowed to significantly increase the selectivity and sensitivity for detection of In3+, Cu2+, and Hg2+. The fluorescence quenching constant (Ksv) values were 2.23 × 105, 1.00 × 105, and 2.74 × 104 M–1, while the limit of detection (LODs) values were 0.06, 0.14, and 0.53 μM, for In3+, Cu2+, and Hg2+, respectively. The concentrations of In3+, Cu2+, and Hg2+ in real environmental samples could be determined by addition of appropriate masking agents, and the recoveries were within the range of 94–110%. This study not only supplied a strategy for constructing a highly sensitive and selective fluorescent probe but also established a platform for simultaneous detection of multiple heavy metal ions in water.
High-Performance Gate-Voltage-Tunable Photodiodes Based on Nb2Pd3Se8/WSe2 Mixed-Dimensional Heterojunctions
Qinggang Qin - ,
Zhengyu Xu - ,
Wei Chen - ,
Xue Liu - ,
Jiawang Chen - ,
Wenshuai Gao - , and
Liang Li *
The mixed-dimensional (MD) van der Waals (vdWs) heterojunction for photodetectors has garnered significant attention owing to its exceptional compatibility and superior quality. Low-dimensional material heterojunctions exhibit unique photoelectric properties attributed to their nanoscale thickness and vdWs contact surfaces. In this work, a novel MD vdWs heterojunction composed of one-dimensional (1D) Nb2Pd3Se8 nanowires and two-dimensional (2D) WSe2 nanosheets is proposed. The heterojunction’s energy band engineering is accomplished by manipulating the Fermi level of the bipolar 2D material via gate voltage, resulting in a rectification characteristic that can be adjusted with gate voltage. Under 685 nm laser irradiation, it demonstrates exceptional self-powered photodetection performance, attaining a photoresponsivity of 1.45 A W–1, an ultrahigh detectivity of 6.8 × 1012 Jones, and an ultrafast response time of 37/64 μs at zero bias. In addition, a broadband photodetector from 255 to 1064 nm is realized. These results demonstrate the great potential of Nb2Pd3Se8/WSe2 MD heterostructures for advanced electronic and optoelectronic devices.
Origin of Persisting Photoresponse of One-Year Aged Two-Dimensional Lead Halide Perovskites Stored in Air under Dark Conditions
Mahesh Eledath-Changarath - ,
Andrés F. Gualdrón-Reyes - ,
Jesús Rodríguez-Romero - ,
Iván Mora-Seró - ,
Isaac Suárez - ,
Rodolfo Canet-Albiach - ,
Maria C. Asensio - ,
Juan P. Martínez-Pastor - ,
Andrii Boichuk - ,
Tetiana Boichuk - ,
Juan F. Sánchez-Royo *- , and
Marie Krečmarová *
Two-dimensional halide perovskites are promising for advanced photonic, optoelectronic, and photovoltaic applications. However, their long-term stability is still a critical factor limiting their implementation into further commercial applications. Here, we present an environmental stability analysis of BA2(MA)n–1PbnI3n+1 (BA = C4H12N+, MA = CH6N+) two-dimensional perovskites with the lowest quantum well thicknesses of n = 1 and n = 2, after 1 year of aging under ambient humidity, oxygen content, and light conditions. We observed that both crystal phases (n = 1 and 2) degraded similarly, resulting in the removal of organic components and crystal decomposition into PbI2, Pb oxides, and Pb hydroxides. However, we have found a significant difference between their aging under ambient light and dark conditions, affecting their degraded morphology and photoactivity. Both crystal phases exposed to ambient light aged into a morphology characterized by the formation of several pinholes and voids, accompanied by photoluminescence degradation. Samples stored under dark conditions surprisingly preserved their photoluminescence activity, which morphologically aged into microrod structures. We conclude that the observed loss of photoactivity of 2D perovskites aged under ambient light is attributed to photoaccelerated degradation processes causing faster crystal surface photo-oxidation accompanied by a creation of multiple I vacancies and hydration of the inner crystal. The retainment of photoactivity in 2D perovskites aged under dark conditions is attributed to slower surface oxidation processes into Pb salts, as confirmed by X-ray photoemission spectroscopy. The formed surface layer even allows for a layer-by-layer degradation and acts as a protection barrier against further additional loss of I atoms and the consequent hydration of the inner part of samples. We demonstrate that light is the most critical external factor accelerating 2D perovskite degradation processes in ambient air and thus affecting their long-term stability. We conclude in this work that perovskite material structural engineering together with their surface passivation or encapsulation strategical techniques applied is an essential step for their further application into long-term stable commercial devices.
Multimodal Locomotion and Dynamic Interaction of Hydrogel Microdisks at the Air–Water Interface under Magnetic and Light Stimuli
Yifan Cheng - ,
Shilu Zhu - ,
Hui Ma - ,
Shengting Zhang - ,
Kun Wei - ,
Shiyu Wu - ,
Yongkang Tang - ,
Ping Liu - ,
Tingting Luo *- ,
Guangli Liu *- , and
Runhuai Yang *
The potential applications of hydrogel microrobots in biomedicine and environmental exploration have sparked significant interest in understanding their behavior under multiphysical fields. This study explores the multimodal locomotion and dynamic interaction of hydrogel microrobots at the air–water interface under magnetic and light stimuli. A pair of hydrogel microrobots at the air–water interface exhibits a transition from cooperative, combined rotation to interactive behavior, involving both rotation and revolution under the influence of a rotating magnetic field (RMF), and a shift from attraction to separation under near-infrared (NIR) light, demonstrating the dynamic modulation of their behaviors in response to different stimuli. Notably, the behavioral patterns of multiple hydrogel microrobots under multiphysical fields indicate that NIR light can enhance interactive motion behaviors under RMFs and extend the range of motion trajectories. Dynamic models for each condition are established and analyzed based on dynamic equilibrium, and their behavior can be modulated by parameters such as magnetic particle concentration, magnetic field frequency, and NIR light intensity. This work introduces a novel strategy for regulating and controlling the dynamic behaviors of hydrogel microrobots, offering new insights into their multiphysical field locomotion.
Multistimuli-Responsive Soft Actuators with Controllable Bionic Motions
Xueting Wang - ,
Wei Zhao - ,
Xinlin Li *- ,
Liwu Liu - ,
Jinsong Leng - , and
Yanju Liu *
Soft actuators with biomimetic self-regulatory intelligence have garnered significant scientific interest due to their potential applications in robotics and advanced functional devices. We present a multistimuli-responsive actuator made from a carbon nitride/carbon nanotube (CN/CNTs) composite film. This film features a molecular switch based on reversible hydrogen bonds, whose asymmetric distribution endows the film with the ability to absorb water unevenly and convert molecular motion into macroscopic movement. By incorporating carboxylated CNTs, the film demonstrates improved mechanical properties and actuation performance. Under ambient humidity stimuli, the actuator can autonomously generate walking and tumbling motions. The CN/CNTs composite film’s actuating behaviors are programmable, enabling diverse deformation modes and complex biomimetic movements. Additionally, the film exhibits excellent photothermal conversion efficiency (74.10 °C/s), allowing for temperature and light-responsive actuation, which can be remotely controlled in real time. These features have enabled the creation of soft robots capable of complex biomimetic actions such as jumping, directional movement, and transporting objects. This research broadens the potential applications of CN-based actuators and paves the way for the development of intelligent soft robots.
Tripartite Detection and Sensing of Toxic Heavy Metals Using a Copper-Based Porphyrin Metal–Organic Framework
Prashanth Kannan *- ,
Ajay Narayan Konda Ravindranath - ,
Sunil Suresh Domala - ,
Mitko Oldfield - ,
Agustin Schiffrin - , and
Dipti Gupta
The detection of heavy metals in water sources is a critical concern for environmental preservation and public health. However, current electrochemical heavy metal sensors suffer from high sensing limits, cross-sensitivity, and poor selectivity. In this work, we present the possibility of an electrochemical sensor based on a copper (Cu) metal–organic framework for the detection of lead, cadmium, and mercury by replacing Cu metal nodes. The working electrode consists of a ∼5 μm thin layer of copper- tetracarboxyphenylporphyrin (Cu-TCPP) sheets that are adsorbed on a glassy carbon electrode (GCE). Upon interaction with Pb2+, Cd2+, and Hg2+, these ions are adsorbed on and incorporated into the metal nodes of the MOF. The adsorbed metallic species can be oxidized to the ionic form (Pb → Pb2+) electrochemically, which results in an oxidation response and enables the quantitative detection of these metals. The oxidation peak currents follow a (mostly) bimodal linear regression with a sensing range of up to 30 μM dependent on the deposition time and an ultralow limit of detection (LoD) of up to 5 nM. The system displays robust and selective sensing in saturated solutions of counterions and interfering metal ions (low error margins of <10%). This work represents the first report of a Cu-TCPP-modified GCE anode as an effective electrode for the sensitive detection of multiple heavy metals and an in-depth study into the Cu replacement kinetics of the Cu-MOF.
Muramyl Dipeptide-Presenting Polymersomes as Artificial Nanobacteria to Boost Systemic Antitumor Immunity
Guanhong Cui - ,
Yinping Sun - ,
Shenqiang Wang - ,
Fenghua Meng - , and
Zhiyuan Zhong *
The clinical efficacy of cancer vaccines is closely related to immunoadjuvants that play a crucial role in magnifying and prolonging the immune response. Muramyl dipeptide (MDP), a minimal and conserved peptidoglycan found in almost all bacteria, can trigger robust immune activation by uniquely antagonizing the nucleotide-binding oligomerization domain 2 (NOD2) pathway. However, its effectiveness has been hindered by limited solubility, poor membrane penetration, and rapid clearance from the body. Here, we introduce MDP-presenting polymersomes as artificial nanobacteria (NBA) to boost the antitumor immune response. The NBA, featuring abundant MDP molecules, induces superior stimulation of immune cells including macrophages and bone marrow-derived dendritic cells (BMDCs) compared to free MDP, likely via facilitating immune cell uptake and cooperatively stimulating systemic NOD2 signaling. Importantly, systemic administration of NBA significantly enhances the chemo-immunotherapy of B16-F10 melanoma-bearing mice pretreated with doxorubicin by reversing the immunosuppressive tumor microenvironment. Furthermore, NBA carrying ovalbumin and B16-F10 cell lysates induces robust OVA-IgG antibody production and effectively inhibit tumor growth, respectively. The artificial nanobacteria hold great promise as a potent systemic immunoadjuvant for cancer immunotherapy.
Atom-Vacancy-Defect-Derived Electric Hysteresis Loops and Stochastic Low-Frequency Noises in Few-Atom Layer MoS2
Mioko Kosugi - ,
Shunta Furuichi - ,
Yung-Chang Lin - ,
Yusuke Kobayashi - ,
Keita Takaki - ,
Takashi Kikkawa - ,
Takashi Taniguchi - ,
Kenji Watanabe - ,
Takashi Kohno - ,
Kazu Suenaga - ,
Eiji Saitoh - ,
Shigeo Maruyama - , and
Junji Haruyama *
Atom-vacancy-defects present in various materials yield numerous interesting physical phenomena, even obstructing high performance in some cases. On the other hand, their valuable applications to novel devices, such as nitrogen vacancy centers in diamond for quantum bits, have gathered significant attention. In particular, these tendencies become more substantial in two-dimensional (2D) (atomically) thin van der Waals layers. However, correlations with various kinds of atom defects are still under exploration. Herein, we find the stochastic behaviors of large hysteresis loops with strong photoresponse in the static electrical properties in few-atom layer semiconductors, molybdenum disulfide (MoS2). The temperature dependence and transmission electron microscopy reveal that they arise from pairs of two neighboring in-plane S-vacancy defects, which predominantly present only around the interface at the MoS2 flake/substrate, with activation energies ∼0.35 eV. The low-frequency (f) (LF) noise measurements clarify a high f shift in the two 1/f2-dependent regimes, implying stochastic behaviors of electric charges through the S-vacancy pairs with high-speed charge(spin) transitions across low kinetic energy barriers between narrow discrete states. The shallow energy sates are formed from the highly uniform S-vacancy pairs interacting with Mo atoms, which act like quantum dots. The observed stochastic operation holds promise for various application, particularly for probabilistic neuromorphic computation in artificial intelligence.
Unravelling the Electrical Field Induced Ion Migration in Flexible OLEDs with PEDOT:PSS Electrodes
Chenxi Liu - ,
Mengze Li - ,
Yifan Wang - ,
Zijie Hou - ,
Jian Chen - ,
Kun Cao - ,
Lihui Liu *- , and
Shufen Chen *
The development of flexible organic light-emitting didoes (FOLEDs) has spurred the research on flexible transparent electrodes (FTEs). Poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) is one of the most attractive FTEs due to its adjustable conductivity and compatibility with low-cost and large-scale solution processing techniques. Significantly, highly efficient FOLEDs have been achieved with modified PEDOT:PSS FTEs. However, the intrinsic mechanisms that contribute to device degradation of FOLEDs utilizing PEDOT:PSS FTEs have not yet been fully elucidated. In this work, three ionic liquids (ILs) are used to enhance the electrical conductivity and mechanical flexibility of PEDOT:PSS FTEs. Simultaneously, the influence of the electric field induced ion migration from PEDOT:PSS FTEs on the operational stability of FOLEDs is unraveled. We find that the ILs with larger ionic radii and higher steric hindrance are beneficial to suppressing the electrical field induced ion migration and improving the operational stability of FOLEDs. Finally, large-area and high-performance FOLEDs are achieved based on the IL of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide modified PEDOT:PSS FTEs, which demonstrate a high current efficiency of 98.1 cd/A and a longer lifetime of 66.7 min. This finding may promote the practical application of PEDOT:PSS FTEs in flexible optoelectronics.
Nitrogen Complex-Driven Vacancy Cluster in Group-III Nitrides
Eui-Cheol Shin - ,
Youngho Kang - , and
Sang Ho Jeon *
A series of experiments have elucidated the primary defects in group-III nitride epilayers, identifying vacancy clusters due to cation migration at interfaces to mitigate strained lattice. While the occurrence of these defects is well-documented, the underlying electronic mechanisms driving vacancy agglomeration in nitrides and their alloys remain poorly understood. In this study, we uncovered a previously unreported ground state of two metal vacancies driven by the migration of kinetically unstable nitrogen atoms using an ab initio approach. Our findings reveal that the mixed covalent-ionic bond character of nitrides is a crucial factor in determining the stability of vacancy clusters. Notably, the relatively strong ionic character of AlN facilitates the formation of exceptionally stable vacancy clusters with a pyramidal nitrogen complex. In contrast, GaN, despite having similar covalent bonding strength, exhibits less stable vacancy clusters due to its weaker ionic character. Moreover, in InN, we observe the formation of molecular-like azide anion that creates a trimer metallic-like bond between indium dangling bonds, accompanied by vigorous indium migration. In the process, we newly identified the formation of a Schottky-Frenkel composite defect. We believe that these novel insights into the bond character and stability of vacancy clusters in nitrides provide a new understanding that could drive the design and optimization of nitride-based materials and electronic devices.
Cross-linking γ-Polyglutamic Acid as a Multifunctional Binder for High-Performance SiOx Anode in Lithium-Ion Batteries
Chuxiong Huang - ,
Jingxi Liang - ,
Huayan Xiao - ,
Xiujuan Wei *- ,
Tiefeng Liu *- ,
Zhan Lin - , and
Shuxing Wu *
SiOx is a highly promising anode material for realizing high-capacity lithium-ion batteries owing to its high theoretical capacity. However, the large volume change during cycling limits its practical application. The development of a binder has been demonstrated as one of the most economical and efficient strategies for enhancing the SiOx anode’s electrochemical performance. In this work, a multifunctional binder (T-PGA) is fabricated by cross-linking γ-polyglutamic acid (PGA) and tannic acid (TA) for SiOx anodes. The introduction of TA into PGA helps to buffer the volume changes of the SiOx anodes, facilitate diffusion of Li+, and construct stable SEI layers. Benefiting from this proposed binder, the SiOx anode maintains a reversible capacity of 973.0 mAh g–1 after 500 cycles at 500 mA g–1 and the full cell, pairing with LiNi0.5Co0.2Mn0.3O2 cathode, delivers a reversible capacity of 133 mA h g–1 (73.2% retention) after 100 cycles. This study offers valuable insights into advanced binders that are used in high-performance Li-ion batteries.
Tunable Chemiluminescence Kinetics with Hierarchically Structured HKUST-1 and Its Sensing Application for Concanavalin A Analysis
Sijie Yuan - ,
Ying Tu - ,
Ru Yu - , and
Fei Nie *
Introducing novel catalysts is essential for developing chemiluminescence (CL) systems that exhibit sustained and robust emission. Traditional Luminol-H2O2 systems typically feature flash-type CL emission. In this study, we discovered that the porous material HKUST-1 can induce a long-lasting and intense CL emission when combined with Luminol-H2O2. This long-term emission signal can be directly detected by the smartphone. By changing the calcination temperature, a series of microporous and hierarchically porous HKUST-1 materials were prepared as catalysts to adjust the kinetic characteristics of the CL signal of Luminol-H2O2 system from flash-type to glow-type. A systematic investigation into the influence of the central metal and ligand, aperture, and particle size of HKUST-1 on the CL kinetic properties revealed that the pore structure has the most pronounced impact on the dynamics of the Luminol-H2O2 CL reaction. Capitalizing on the intense emission of the HKUST-1-catalyzed Luminol-H2O2 system, we established a CL sandwich immunoassay strategy for concanavalin A (ConA), demonstrating good linearity and low detection limit. This research presents a significant endeavor in modulating the dynamics of CL signal emissions.
Solution-Processed TiO2/ZnFe2O4 Heterostructure for Stable Multilevel Memristor with Room-Temperature Reactive Gas Selectivity
Priya Kaith - ,
Parul Garg - ,
Vishal Nagar - , and
Ashok Bera *
Solution-processed oxide-based heterojunctions that work in diverse directions will be ideal alternatives for cost-effective, stable, and multifunctional devices. Here, we have reported a stable multilevel resistive switching (RS) at the solution-processed TiO2/ZnFe2O4 heterointerface with endurance stability over 104 cycles and retention over 105 s. It can maintain the switching after dripping water onto the device, followed by drying at 100 °C and at an operating temperature of up to 200 °C. As the switching mechanism is governed by filamentary and interface-dominated charge conduction, our device shows additional tunability in the low resistance state (LRS) by changing environmental conditions. The inability to form filaments results in almost negligible switching under a vacuum or inert environment with an LRS loss. Meanwhile, the presence of reducing gas leads to a depletion layer lowering at the TiO2/ZnFe2O4 heterointerface by removing the surface-adsorbed oxygen molecules that help filament conduction through the interface and, hence, a change in LRS. Furthermore, different reaction capacities of different reactive gas environments with the surface-adsorbed oxygen molecule lead to discrete ON–OFF ratios, presenting a pathway to identify several reactive vapors like ammonia, formaldehyde, and acetone at room temperature and presenting a new approach for integrating RS and room temperature gas sensing in the multifunctional device technology.
Tunable Broadband NIR-II Emission via Cr4+-Er3+ Energy Transfer in CaMgGeO4:Cr4+,Er3+ Phosphors for Nondestructive Analysis
Hanyu Hu - ,
Zeyu Lyu *- ,
Dashuai Sun - ,
Shuai Wei - ,
Jia Liu - ,
Xin Wang - ,
Luhui Zhou - , and
Hongpeng You *
Although there have been numerous reports on broadband near-infrared (NIR) emitting phosphors, their emissions are mainly concentrated in the range of 700–1000 nm (NIR-I). Herein, we successfully synthesized a broadband near-infrared phosphor CaMgGeO4:Cr4+(CMG:Cr4+) with an emission in the range of 1000–1600 nm (NIR-II). The introduction of Er3+ ions into CMG:Cr4+ resulted in a wider near-infrared emission phosphor CaMgGeO4:Cr4+,Er3+ (fwhm = 361 nm), compensating for the luminescence of 1500–1600 nm. More importantly, an energy transfer from Cr4+ to Er3+ ions has been discovered. Furthermore, a NIR pc-LED was fabricated by combining the CMG:Cr4+,Er3+ phosphor with a 590 nm chip. The changes in intensity and profile of the transmission spectra of light passing through different liquids reveal its potential application in organic compound recognition. This work opens a direction for the development of NIR-II phosphors.
A Developed Approach for Synthesizing Novel Fe3O4/FeO/BaCl2 Composites with Broadband and High-Efficiency Microwave Absorption Performance
Zhanyu Ma - ,
Ying Han - ,
Bin Tan - ,
Cuicui Yang - , and
Zhiwei Liu *
Designing high-performance microwave absorbing materials that are thin and exhibit strong absorption capabilities across a wide frequency range is critical for mitigating electromagnetic pollution through a simple, highly adaptable, and cost-effective approach. However, achieving these three targets remains a significant challenge. In this research a simple approach suitable for large-scale production of microwave absorbing materials, namely, Fe3O4/FeO/BaCl2 composites, is proposed, which includes the processes of chemical coprecipitation and calcination. The above approach can adjust the mass ratio of Fe3O4/FeO while prompt the formation of BaCl2 with mesoporous structure on the surface of Fe3O4/FeO, meeting the need for desirable microwave absorbing performance. Subsequently, the impacts of varying mass ratios of the Fe3O4/FeO/BaCl2 composites on microstructures, magnetic properties, and microwave absorption properties were examined. Based on this investigation, a mass ratio close to 3.5:5.5:1 was determined to be optimal. At this ratio, the Fe3O4/FeO/BaCl2 composites realize an effective absorption bandwidth of 6.70 GHz at only 1.16 mm thickness, covering the whole Ku-band, and the maximum reflection loss can be close to −46.8 dB at 1.4 mm. The robust microwave absorption performance of Fe3O4/FeO/BaCl2 composites can be attributed to heterostructured multi-interface structural design, the comprehensive effects of multiple reflections and dielectric/magnetic losses induced by BaCl2 with mesoporous structure as well as the aggregated Fe3O4/FeO particles. This work may offer insights into designing and preparing effective microwave absorption materials.
MXene/WO3 Sensor Array with Improved SNN Algorithm for Accurate Identification of Toxic Gases
Liangchao Guo - ,
Junke Wang - ,
Haoran Han - ,
Peng Wang - ,
Yunxiang Lu - ,
Qilong Yuan - ,
Chunyu Du - ,
Shuo Yin - ,
Ye Zhou *- , and
Chao Zhang *
Gas sensing is pivotal in critical areas such as industrial production and food safety. This study explores the gas classification capabilities of MXene-based gas sensors. Pure V2CTx MXene and an MXene/WO3 nanocomposite were synthesized, and MXene-based gas sensors were integrated into a 2 × 2 rudimentary electronic nose array. The tests on gas sensitivity revealed that the inclusion of WO3 nanoparticles (NPs) boosted the sensor’s response to 10 ppm of NO2 from 2.82 to 3.45 at room temperature. Moreover, the sensor showcased a rapid response/recovery duration of 74.5/149.0 s, excellent environmental stability, and long-term reliable sensing performance. Furthermore, we have improved the method of accurately identifying four toxic gases detected by an MXene-based sensor array using a spiking neural network (SNN) based on the memristive system. Also, the performance of this identification method revealed that the method achieved 95.83% accuracy in the identification of the four gases. Notably, the improved SNN demonstrated approximately 5% higher accuracy than the other gas recognition algorithm. These results highlight the potential of SNN as a powerful tool to accurately and reliably identify toxic gases based on the gas sensor array.
Dual-Mode Stretchable Emitter with Programmable Emissivity and Air Permeability
Yinhyui Joo - ,
Dongkyun Kang - , and
Myeongkyu Lee *
Materials with anisotropic emission characteristics have attracted considerable attention for thermal management. Although many dual-mode emitters have been developed for this purpose in the form of textiles, multilayer films, and photonic structures, multiple functionalities are essential for their versatile applications. Herein, a highly stretchable dual-mode emitter with programmable emissivity and air permeability is presented. The emitter comprises a planar Ge2Sb2Te5 (GST) cavity on one side of a perforated elastomer substrate and an infrared-reflecting metal layer on the other side. With a laser-induced phase transition from amorphous to crystalline GST, the emitter exhibits a large emissivity difference of 0.52 between both sides. The dual-mode emitter remains highly stable without mechanical failure after repeated stretching cycles to a strain of 50%. This air-permeable and stretchable emitter can be attached to any curved surface, including the human body. The GST-side emissivity can be programmed into an arbitrary emissivity pattern using a spatially modulated laser beam, ultimately enabling the printing of mutually independent visible and thermal images in a single emitter. This study provides a promising structure for multispectral optical security as well as thermal management.
Rational Design of Two-Dimensional MA2Z4 Monolayers as Effective Anchoring Materials for Lithium–Sulfur Batteries
Dingyanyan Zhou - ,
Lujie Jin - ,
Yujin Ji *- , and
Youyong Li *
Advances in lithium–sulfur batteries (LSBs) are impeded by the inefficiency of anchoring materials in facilitating long-term cycling and rate performance. To address this challenge, an exploration of two-dimensional MA2Z4 monolayers as potential anchoring materials for LSBs is proposed based on density functional theory calculations and machine learning (ML) techniques. Adsorption features, sulfur reduction reaction behaviors, and solvent interactions are assessed and analyzed; and MoGe2N4 and WGe2N4 are identified as the most promising candidates because they have optimal adsorption energies for lithium polysulfides to suppress the shuttle effect and exhibit enhanced catalytic activity. Meanwhile, ML analysis highlights the critical influence of the electronegativity of element Z in MA2Z4 on anchoring properties, providing valuable insights into future anchoring material design for high-performance LSBs.
Incorporation of Fe/FeOx Nanoparticles into Interlinked N-Doped Porous Carbon Nanofiber Networks to Realizing Sequential Catalytic Conversion of Lithium–Sulfur Batteries
Xing-He Zhao - ,
Xue-Yan Wu - ,
Qian-Qian Hao - ,
Yu-Si Liu *- ,
Kai-Xue Wang *- , and
Jie-Sheng Chen *
Lithium–sulfur (Li–S) batteries (LSBs) with energy density (2600 Wh/kg) much higher than typical Li-ion batteries (150–300 Wh/kg) have received considerable attention. However, the insulation nature of solid sulfur species and the high activation barrier of lithium polysulfides (LiPSs) lead to slow sulfur redox kinetics. By the introduction of catalytic materials, the effective adsorption of LiPSs, and significantly reduced conversion, energy barriers are expected to be achieved, thereby sharpening electrochemical reaction kinetics and fundamentally addressing these challenges. In this work, a multifunctional catalyst consisting of highly dispersed heterostructure Fe–Fe2O3 nanoparticles was synthesized and introduced to the LSB. Experimental and theoretical analyses revealed that the spontaneous interfacial charge redistribution, resulting in moderate polysulfide adsorption, facilitates the transfer of polysulfides and diffusion of electrons at heterogeneous interfaces. This catalyst achieves sequential catalytic processes on polysulfides with different components. Furthermore, the reduced conversion energy barriers enhanced the catalytic activity of Fe/Fe2O3–NG for expediting LiPS conversion. Consequently, the battery exhibited long-term stability for 300 cycles with 0.03% capacity decay per cycle at 5C. This work provides in-depth insight into the fundamental design principles of effective catalysts for LSBs.
In-Situ Constructing N,S-Codoped Carbon Heterointerface for High-Rate Cathode of Sodium-Ion Batteries
Hanrui Ding - ,
Yujin Li - ,
Xinyu Hu - ,
Jie Li - ,
Zhenglei Geng - ,
Yuhao Liu - ,
Wentao Deng - ,
Guoqiang Zou - ,
Li Yang *- ,
Hongshuai Hou *- , and
Xiaobo Ji
Na3V2(PO4)3 (NVP) is considered one of the promising choices for cathodes of sodium-ion batteries, but the poor conductivity resulted inferior rate performance limited the practical development of NVP cathodes. In this study, we successfully synthesized N/S dual-atom doped carbon coatings in situ through a simple one-step solid-state sintering method. The uniformly coated carbon layer can inhibit the agglomeration and growth of active materials during the sintering process, shorten the Na+ migration path, and increase the contact area with the electrolyte, thus facilitating rapid Na+ migration. Notably, the doping of N elements can alter the electron distribution of carbon coating, enhancing electron conductivity. Furthermore, the introduction of S elements in the carbon layer can induce the formation of stable C–S–C bonds in the molecular layer, expanding the interlayer spacing, which is beneficial for Na+ transport and storage. Therefore, the modified NVP@NSC composite provides a high specific capacity of 90.3 mAh g–1 at a rate of 20 C, with a capacity retention rate of 94.4% after 8000 cycles, demonstrating excellent stability at high current densities. Moreover, the full cell exhibits remarkable electrochemical performance at 5 C. This research contributes to the practical development of NVP cathodes.
A Smartphone-Enabled Colorimetric Microneedle Sensing Platform for Rapid Detection of Ascorbic Acid in Fruits
Rui Li - ,
Zhiqing Liu - ,
Youpeng Xiong - ,
Xianghan Zhang - ,
Long Chen - ,
Danya Li - ,
Chao Huang - ,
Shui Yu - , and
Xin Jia *
Achieving rapid extraction and detection of analytical solutions from plant tissues to circumvent cumbersome procedures and reduce the dependence on detection instruments remains a challenge. Herein, a colorimetric microneedle integrated platform was developed for the rapid extraction and detection of plant fluids for testing purposes. Colorimetric microneedle patches (CMPs) offer a swift and effective method to swiftly extract and detect ascorbic acid (AA) within 10 min from various fruit crops like mango, nectarine, apple, pear, and kiwifruit, facilitated by a smartphone application. CMPs are constructed for the rapid and sensitive analysis of AA with good linearity amid the range 0.05–25 μM and a low limit of detection of 30 nM. The novel CMPs demonstrate significant potential as a rapid detection platform for AA in plants. CMPs offer significant advantages over traditional ultraviolet spectrophotometry, such as simplified operational procedures and accelerated extraction and detection processes. This establishes robust groundwork for conducting in situ extraction and molecular detection of diverse crops across a spectrum of application scenarios.
A Dry Patch with In Situ Solid-to-Gel Transformation for All-in-One Skin Wound Care
Yong Liu *- ,
Kaiyuan Wang - ,
Wenwen Ren - ,
Nannan Gao - ,
Juanjuan Li *- , and
Hao Wang *
Hydrogel-based dressing materials offer significant potential in expediting skin wound healing. Nevertheless, they face several challenges: poor adhesion to wound tissues, difficulties in preservation under ambient conditions, and limited multifunctionality to support all wound healing stages. In this work, a dry patch is designed to address these persistent issues by featuring an in situ solid-to-gel transformation and Janus wet tissue adhesiveness. The HGP patch integrates a wet adhesive layer combining dopamine-conjugated hyaluronic acid (HD) and poly(acrylic acid) (PAA), a drug-loading layer comprising gelatin (Gel), and a nonadhesive gelation layer of poly(vinyl alcohol) (PVA) and sodium alginate (SA). This hierarchical structural design confers exceptional wound adhesion, hemostatic capabilities, and antibacterial and antioxidant activities, as well as immune regulatory properties. These attributes collectively support accelerated skin wound healing, particularly in cases complicated by bacterial infections. This research charts an approach to engineer hydrogel-based wound dressings through on-site hydrogel formation, thus advancing the treatment of wounds afflicted with complex infections.
Ultralight SiO2 Nanofiber-Reinforced Graphene Aerogels for Multifunctional Electromagnetic Wave Absorber
Haoyuan Tian - ,
Jingpeng Lin - ,
Jiurong Liu - ,
Lei Li *- ,
Bin Li - ,
Sinan Zheng - ,
Wei Liu - ,
Chang Liu *- ,
Zhihui Zeng *- , and
Na Wu *
The high-efficiency utilization of two-dimensional (2D) graphene layers for developing durable multifunctional electromagnetic wave (EMW) absorbing aerogels is highly demanded yet remains challenging. Here, renewable, low-density, high-strength, and large-aspect-ratio ceramic silicon dioxide (SiO2) nanofibers were efficiently prepared to assist in the preparation of ultralight yet robust, highly elastic, and hydrophobic graphene aerogels using facile, scalable freeze-drying followed by a carbonization approach. The ceramic nanofibers efficiently prevent the agglomeration of graphene and enhance interfacial interactions, significantly promoting mechanical strength. In addition to the high conduction loss capability derived from the interconnected graphene network, high interfacial polarization derived by abundant heterogeneous interfaces is accomplished for the three-dimensional (3D) hybrid aerogels. The hybrid aerogels thus showcase excellent EMW absorption performance, involving a minimum reflection loss of −74.5 dB at 1.8 mm and an effective absorption bandwidth of 5.7 GHz, comparable to those of the best EMW absorbers. Furthermore, the integration of one-dimensional SiO2 and 2D graphene into 3D hybrid aerogels enables remarkable photothermal antibacterial, photothermal oil absorption, and thermal insulation performances. This work thus provides a type of ultralight ceramic/graphene aerogel with a high-efficiency utilization of graphene for accomplishing high-performance multifunctional applications.
Machine Learning-Assisted Bayesian Optimization for the Discovery of Effective Additives for Dendrite Suppression in Lithium Metal Batteries
Damien K. J. Lee - ,
Teck Leong Tan - , and
Man-Fai Ng *
In the pursuit of enhancing the performance and safety of lithium (Li)-metal batteries, the discovery of effective electrolyte additives to suppress Li dendrites has emerged as a paramount objective. In this study, we employ an inverse design strategy to identify potential additives for dendrite mitigation. Two key mechanisms, namely, the formation of robust solid electrolyte interphase layers and the leveling mechanism, serve as the foundation for our investigation. Our inverse design strategy is guided by molecular properties such as the lowest unoccupied molecular orbital energy and interaction energy upon Li surface adsorption. An active learning process utilizing Bayesian optimization (BO) was utilized to identify potential molecules with ideal properties. Through this screening process, we uncover a collection of 62 molecules with the potential to act as SEI-forming additives, along with 106 molecules for leveling additives, both surpassing the performance of established additives reported in the literature. This work highlights the potential of BO methods in computationally based inverse design of materials for many applications, and the discovered additives could potentially boost the commercialization of Li–metal batteries.
November 4, 2024
How Does Li2C4O4 Prelithiation Additive Influence the Solid Electrolyte Interphase of Dual Carbon Lithium-Ion Capacitors?
Miguel Granados-Moreno - ,
Rosalía Cid *- ,
Maria Arnaiz - ,
Eider Goikolea - , and
Jon Ajuria *
Prelithiation is a critical step in dual carbon lithium-ion capacitors (LICs) due to the lack of Li+ in the system, which needs to be incorporated externally to avoid electrolyte depletion. Several prelithiation techniques have been developed over the years, and recently, dilithium squarate (Li2C4O4) has been reported as an air-stable, easy to synthesize, safe, and cost-effective prelithiation reagent for LICs. Li2C4O4 has successfully been used in a wide range of chemistries, and its integration into positive electrodes has been scaled up to roll-to-roll processing and demonstrated in multilayer pouch cells. However, its influence in the solid electrolyte interphase (SEI) has not yet been studied. In this work, the SEI formed on the hard carbon (HC) negative electrode when using Li2C4O4 as a prelithiation agent has been studied by X-ray photoelectron spectroscopy (XPS). The electrode surface has been analyzed in the lithiated and delithiated states along the first lithiation cycle, as well as at the end of the prelithiation protocol, to gain insight into the SEI formation and evolution during the prelithiation process. In addition, an aging test has been carried out to study the long-term SEI stability. We have observed that the use of Li2C4O4 induces a chemical modification in the composition of the SEI with respect to the SEI that forms by using a standard electrochemical prelithiation process, resulting in a less soluble interface. Therefore, the chemical composition of the SEI is stable over cycling. Those findings confer to Li2C4O4 the ability to tune the SEI of the devices, enabling its use in LICs and LIBs not only as a prelithiation agent but also as a film-forming additive.
Dual Emission and Low-Temperature Afterglow in Xanthone-Dibenzoazepine for High EQE Host–Guest OLEDs with Low-Efficiency Roll-Off
Komal Vasant Barhate - ,
Pramya Ranjan Chanda - ,
Mahesh Poojary - ,
Sangita Bose *- , and
Neeraj Agarwal *
Research has been driven to demonstrate organic light-emitting diodes (OLEDs) with high efficiency, and in the quest for new materials, thermally activated delayed fluorescence (TADF) emitters have been employed. Preparation of donor–acceptor (D-A) π-conjugates is a useful guideline for developing TADF emitters. TADF emitters have shown excellent progress and high maximum external quantum efficiency (EQEmax) for OLEDs in the recent past; however, they suffer with substantial roll-off resulting in a decrease in their efficiency. In order to have efficient OLED emitters with less efficiency roll-off, we designed a xanthone-amine derivative with twisted electron-rich dibenzoazepine having limited rotation at the donor–acceptor bond. Xan-Azepine shows solvent polarity-dependent fluorescence in the range of 441– 597 nm having a lifetime below 10 ns. At 77 K in Me-THF, a triplet at 557 nm was observed having a decay lifetime of 0.75 s and an afterglow for about 6 s. In powder, it shows dual emission, i.e., fluorescence (490 and 6 ns) and phosphorescence (530 nm and 192 μs) at ambient conditions. The energy difference between the singlet and triplet energy levels of Xan-Azepine is found to be 0.18 eV in the powder sample. Its blend in 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP) showed delayed fluorescence with a lifetime of 118 μs at 300 K, while it reduced to 84 μs at 150 K. These observations suggest the TADF nature of Xan-Azepine in its CBP blend. OLED devices of Xan-Azepine showing a turn-on voltage of 2.8 V and a EQEmax of 12% were successfully fabricated. In the doped films of Xan-Azepine (5 wt %) with CBP, a maximum luminescence of 5980 Cd/m2 at a current density of 70 mA/cm2 was obtained, resulting in devices with low-efficiency roll-off (2.75%).
Low-Energy Photoresponsive Magnetic-Assisted Cleaning Microrobots for Removal of Microplastics in Water Environments
Zhichao Wang - ,
Lei Xu - ,
Xihang Cai - , and
Tingting Yu *
In the global ecosystem, microplastic pollution pervades extensively, exerting profound and detrimental effects on marine life and human well-being. However, conventional removal methods are usually limited to chemical flocculation and physical filtration but are insufficient to remove extremely small microplastics. Therefore, developing a comprehensive strategy to address the threat posed by microplastics is imperative. Here, we report a low-energy photoresponsive magnetic-assisted cleaning microrobot (LMCM) composed of photocatalytic material (Ag@Bi2WO6) and magnetic nanoparticles (Fe3O4), which can be used for the active removal of microplastics from water environments. Due to the diffusion electrophoresis effect, the low-energy photoresponsive cleaning microrobots (LCMs) are formed by spontaneous assembly of Ag@Bi2WO6, which can continuously adsorb microplastics in a water environment. Particularly, the effective attraction distance of LCMs on microplastics exceeds 100 μm. After assembling the Fe3O4 nanoparticles, LMCMs can clean microplastics in groups from water environments under the control of a magnetic field. Utilizing precision manipulation and group control, LMCMs demonstrate a remarkable 98% cleaning efficiency in 93 s and can be recovered under the control of the directional magnetic field. This eco-friendly and energy-efficient microrobot is expected to provide a viable strategy to tackle the threat of microplastics or promote industrial microplastic removal.
In Situ Solid-State Dewetting of Ag–Au–Pd Alloy: From Macro- to Nanoscale
Peifen Lyu - ,
Filipe Matusalem - ,
Ece Deniz - ,
Alexandre Reily Rocha - , and
Marina S. Leite *
This publication is Open Access under the license indicated. Learn More
Metal alloy nanostructures represent a promising platform for next-generation nanophotonic devices, surpassing the limitations of pure metals by offering additional “buttons” for tailoring their optical properties by compositional variations. While alloyed nanoparticles hold great potential, their scalability and underexplored optical behavior still limit their application. Here, we establish a systematic approach to quantifying the unique optical behavior of the AgAuPd ternary system while providing a direct comparison with its pure constituent metals. Computationally, we analyze their electronic structure and uncover the transition of Pd d states to Pd/Ag hybridized s states in the bulk form, explaining the similar optical properties observed between Pd and AgAuPd. Experimentally, we fabricate pure metal and fully alloyed nanoparticles through solid-state dewetting, a scalable method. During the process, we trace the optical transition in the systems from the initial thin film stage to the final nanoparticle stage with in situ ellipsometry. We reveal the interplay between optical properties influenced by chemical interdiffusion and localized surface plasmon resonance arising from morphological changes with ex situ surface characterizations. Additionally, we analytically implement a metallic layer derived from the ternary system in a trilayer device, resulting in a single-time and irreversible color filter, to demonstrate an application encompassing a lithography-free and cost-effective route for nanophotonic devices.
Engineering Electrolytes with Transition Metal Ions for the Rapid Sulfur Redox and In Situ Solidification of Polysulfides in Lithium–Sulfur Batteries
Jiahao Gu - ,
Zhaoyang Li - ,
Bo Hong *- ,
Mengran Wang - ,
Zhian Zhang - ,
Yanqing Lai - ,
Jie Li - , and
Libo Zhang
Lithium–sulfur (Li–S) batteries have been pursued due to their high theoretical energy density and superb cost-effectiveness. However, the dissolution–conversion mechanism of sulfur inevitably leads to shuttle effects and interface passivation issues, which impede Li–S battery practical application. Herein, the approach of adopting transition metal salts (CoI2) to engineering the electrolyte is proposed. Different from anchored transition metal catalysts in the cathode, soluble cobalt ions can chemically reduce and solidify polysulfides, alleviating the dependence of sulfur conversion on the conductive interface while suppressing the shuttle effect. Importantly, all elements in CoI2 are in the lowest valence state and solid complexes are formed after the redox reaction, which prevents the migration of high valent Co3+ to the anode, thus overcoming the poor compatibility between redox mediator and Li anode. Notably, I3– has the function of eliminating dead sulfur and dead lithium, which we apply to Li–S batteries. After activating I3– at a certain frequency, Li–S batteries indeed achieve a longer and more stable cycle life. By combining the regulatory behavior of anions and cations, the electrolyte is engineered for Li–S batteries with high capacity, long lifespan, and excellent rate performance.
pH-Controlled Synthesis of Mercury Cyanamides/Carbodiimides and Piezocatalytic Studies of the Noncentrosymmetric Ones
Jiangguli Peng - ,
YiXu Wang - ,
Michal Fečík - ,
Lkhamsuren Bayarjargal - , and
Richard Dronskowski *
An entire series of mercury cyanamides/carbodiimides, including two new materials─Hg2(NCN)Cl2 (Pcnb, Z = 4, a = 9.109(1) Å, b = 15.386(1) Å, c = 8.017(3) Å) and Hg4(NCN)3Cl2 (Pccn, Z = 4, a = 11.330(3) Å, b = 12.905(9) Å, c = 6.844(6) Å)─has been synthesized by controlling the pH of the parent solution, and their crystal structures were solved and refined based on synchrotron PXRD data. To determine the symmetry of the new phases with high certainty, experimental second-harmonic generation measurements and theoretical DFT calculations were used. Evaluation of band gaps was performed using Tauc plots and complemented by periodic DFT calculations to verify the type of indirect/direct semiconductors of these cyanamides/carbodiimides. These calculations were also utilized to obtain further information on chemical bonding about Hg–N, Hg–Cl, and C–N from first principles. Moreover, the noncentrosymmetric cyanamide Hg3(NCN)2Cl2 was first applied to a piezocatalytic field, resulting in a 50% efficiency in degrading a common organic dye. This work provides fresh insight in the synthesis of inorganic nitridocarbonates by the pH adjustment and highlights the interplay between the experiment and theory, and it also offers a promising approach to applying noncentrosymmetric cyanamides into the degradation of environmental pollutants.
Viscoelastic-Support-Layer-Based Macroscopic Conformal Transfer of van der Waals Materials Compatible with Plasmonic Application
Chaeyeon Moon - ,
Dongmin Moon - ,
Nahun Kim - ,
Hajung Park - ,
Jaeseung Im - ,
Heewoo Lee - ,
Junhyuk Kwon - ,
Sungho Park - ,
Sehwa Chung - ,
Dong Hak Oh - ,
Ji Min Bae - ,
Soobong Choi - ,
Seung Ryong Park - ,
Sung Ju Hong *- , and
Young-Mi Bahk *
This study showcases the conformal geometries of van der Waals materials with metallic structures utilizing viscoelastic support layers. Mechanically exfoliated nanometer-thick graphite flakes were transferred onto metal structures with various side slopes using two different polymers: polycarbonate (PC) and polyethylene (PE). We proposed a morphology-based evaluation of the macroscale conformity that can contribute to the selection of a proper support layer. Although both support layers ensured high conformity on the sloped side, the PE layer offered superior conformity on the vertical metal structure. To further investigate the impact of conformal structures, we compared the terahertz transmission changes of a metal bowtie antenna before and after transferring graphite onto the bowtie gap for two distinct conformal structures. The conformity of graphite to the metal gap structure significantly influenced the optical response in the terahertz frequency regime. This suggests that the conformal structuring technique can be leveraged in various terahertz devices composed of metals and van der Waals materials, opening avenues for quantitative analysis in light–matter interactions.
Spraying-Deposited Transparent p-Type Sn-Doped CuI Film and Its Ultrahigh-Speed Self-Powered Photodetector
Li Xu - ,
Haowei Liu - ,
Jianmei Xu - ,
Wei Zhou - ,
Zhihong Yang - ,
Wei Xu - , and
Jian Sun *
The exploitation of simply processed p-type semiconductors and photodetectors with promising optoelectrical properties remains challenging yet essential for current and future advanced optoelectronic applications. Transparent p-type CuI and Sn-doped CuI (Cu–Sn–I) films and their self-powered photodetectors have been successfully fabricated by the spraying method. It is found that the incorporation of Sn dopants enhances the optical, electrical, and photoelectric properties of CuI thin films as well as their corresponding self-powered heterojunction photodetectors. This improvement of the optoelectrical properties of the Cu–Sn–I film and its photodetector can be attributed to the adjustment of the acceptor defect level and increased hole concentration resulting from Sn doping. The Cu–Sn–I/n-Si photodetector exhibits a responsivity of 10.7 mA/W, a detectivity of 6.79 × 1011 Jones, and a response time of 77 μs/30 μs (0 V bias). The response time exhibits the fastest rise and decay times compared with the other CuI-based self-powered UV photodetectors in recent years, showcasing promising applications in the realm of transparent electronics moving forward. This study also presents an effective strategy for enhancing the electrical properties of p-type semiconductors and devices through effective doping.
Influence of Electrolyte Saturation on the Performance of Li–O2 Batteries
Amirhossein Sarabandi - ,
Andre Adam - , and
Xianglin Li *
Electrolyte saturation can strongly affect the Li–O2 battery performance. However, it is unclear to what extent saturation reduction will impact the battery capacity. In this study, we investigated the influence of electrolyte saturation and distribution within a porous positive electrode on the deep discharge–charge capacities and cycling stability. The study used both models and experiments to investigate the change of electrolyte distribution, double-layer capacitance, ohmic resistance, and O2 concentration in the positive electrode at different electrolyte saturations. Results revealed that electrodes with 60% electrolyte saturation achieved almost the same maximum discharge (6.38 vs 6.76 mAh/cm2) and charge (5.52 vs 5.65 mAh/cm2) capacities with fully saturated electrodes. The partially wet positive electrode (40% saturation) obtained more cycles than the electrode with 100% saturation before the discharge capacity dropped below the cutoff point. However, the electrode with 40% saturation had a low average charging efficiency of 88.76%, whereas the fully saturated electrode obtained 98.96% charging efficiency. Moreover, the fully wet positive electrode had the lowest overpotential during cycling (1.26–1.39 V). The measured electrochemically active surface areas showed that even 40% saturation could sufficiently wet the positive electrode surface and obtain a double-layer capacitance (18.12 mF) similar to that with 100% saturation (20.4 mF). Furthermore, a considerable increase in O2 concentration at wetted surface areas was observed for the electrolyte saturation of less than 60% due to the significantly higher O2 diffusivity in the gas phase.
WiFi-Powered Sensor Integrated into a Smart Glove with a Fully Fabric Antenna for the Human–Machine Interface
Kok-Tong Lee - ,
Eng-Hock Lim - ,
Chun-Hui Tan - ,
Jen-Hahn Low - ,
Kwong-Long Wong - ,
Cao Guan *- , and
Pei-Song Chee *
The integration of flexible sensors into human–machine interfaces (HMIs) is in increasing demand for intuitive and effective manipulation. Traditional glove-based HMIs, constrained by nonconformal rigid structures or the need for bulky batteries, face limitations in continuous operation. Addressing this, we introduce yarn-based bend sensors in our smart glove, which are wirelessly powered and harvest energy from a fully textile 5.8 GHz WiFi-band antenna receiver. These sensors exhibit a gauge factor (GF) of 5.60 for strains ranging from 0 to 10%. They show a consistent performance regardless of the straining frequency when being stretched and released at frequencies between 0.1 and 0.7 Hz. This reliability ensures that the sensor output is solely dependent on the yarn’s elongation. Accurately detecting finger-bending movements from 0° to 90° in a virtual environment, the sensors enable enhanced degrees of freedom for human finger interaction. When integrated with advanced machine-learning techniques, the system achieves a classification accuracy of 98.75% for object recognition, demonstrating its potential for precise and accurate HMI. Unlike conventional near-field energy transfer methods that rely on magnetic flux and are limited by power loss over distance, our fully textile design effectively harvests microwave energy, showing no voltage deterioration up to 1 m away. This minimalist microwave-powered smart glove represents a significant advancement, offering a viable and practical solution for developing intuitive and reliable HMIs.
Covalent Organic Framework Packed Nanoporous Membrane for Continuous Removal of Bisphenol A from Agricultural Irrigation Wastewater
Haonan Qu - ,
Defu An - ,
Guang Li - ,
Weiwei Xu - ,
Cuiguang Ma - ,
Haifan Zhang - ,
Ehsan Bahojb Noruzi - ,
Jing Cheng - ,
Chuan Zhou *- ,
Govindasami Periyasami *- , and
Haibing Li *
BPA, a typical endocrine disruptor, poses a significant threat to the growth of crops and thereby jeopardizes sustainable agriculture products and human health. In this work, a water-stabilized imine covalent organic framework (TpBD-COF) packed nanochannel membrane was constructed. The TpBD-COF membrane achieves high selective removal of BPA attributed to the subdivision of the pores by the filled COF, which further reduces the porous size and effectively eliminates the distance barrier between the selective sites of TpBD-COF membranes and BPA. The selective removal ratio of BPA was 5.79 times higher than that of the bare membrane, while the removal capacity reached 6.78 nM cm–2 min–1. It can eliminate BPA from irrigation wastewater and ensure crop growth. The application of COF-filled nanoporous membrane provides not only a size-matching strategy for the development of specific continuous removal of BPA but also a theoretical reference for membrane removal of other organic pollutants in agricultural irrigation water environment.
A Fe3+-Doped TiO2 Superhydrophilic Coating with Transparent and Long-Lasting Antifogging Properties Constructed Based on Nanostructured Antireflective and Capillary Anchoring Effects
Yuying Yin - ,
Meiru Huang - ,
Luqi Liu - ,
Guiping Zhou - ,
Luli Shen - ,
Gang Wang - ,
Zhixiang Zeng *- , and
Fuliang Ma *
Superhydrophilic surfaces have attracted great interest in antifogging applications. However, balancing long-lasting superhydrophilicity and high transparency on antifogging surfaces remains a serious problem to be solved. The objective of this work is to prepare superhydrophilic coatings with transparent and long-lasting antifogging properties. In the design, a three-step method was used to obtain the target coatings: (1) magnetron sputtering deposition of a TiN film to provide high intensity, (2) anodic oxidation of the TiN film to obtain TiO2 nanoparticles intended for nanostructured antireflective and capillary structures, and (3) the sol–gel method for the preparation of Fe3+-doped TiO2 coatings using spin-coating in order to achieve superhydrophilicity. The nanostructures, due to their subwavelength dimensions, not only provide high transparency but also recoverable superhydrophilicity owing to the presence of a capillary anchoring effect that prevents the coating from dissolving and peeling off after soaking. The doping of Fe3+ broadened the photoresponse range and maintained the long-lasting superhydrophilicity. Tests showed that the 2 mol % Fe3+-doped TiO2 coating with nanostructures exhibited the highest transparency, longest-lasting superhydrophilicity, and antifogging properties. Furthermore, the coating provided excellent self-cleaning properties, as well as mechanical and chemical stability.
Tetraphenylethene-Containing Nanofilm via Interfacial Confinement Self-Assembly for Fluorescent Monitoring of SOCl2 Leakage in a Li–SOCl2 Battery Electrolyte
Tianyu Zhao - ,
Zhen Yan - ,
Taihong Liu *- ,
Liping Ding *- , and
Yu Fang
Lithium thionyl chloride (Li–SOCl2) batteries are widely used due to their high energy density and long shelf life. However, the corrosive nature of SOCl2 poses a safety hazard, necessitating effective leak detection methods. We report an approach for real-time fluorescent detection of SOCl2 leakage in Li–SOCl2 batteries using a tetraphenylethene-based nanofilm. The nanofilms were prepared through the interfacial confined self-assembly method and exhibit excellent flexibility, homogeneity, tunable size and thickness, and adaptability to various substrates, enabling easy integration into sensor devices. They possess high photochemical stability and a photoluminescence quantum yield exceeding 25%, demonstrating their potential as high-performance fluorescent sensing material. The nanofilms also exhibit high sensitivity, good reproducibility, and selectivity toward SOCl2 detection. Upon exposure to SOCl2 vapor, the nanofilm shows a red-shifted and fluorescence quenching response, attributed to the protonation of the acylhydrazone bond in the nanofilm by the hydrolysis product of SOCl2, which disrupts the electronic structure of the nanofilm and leads to a decrease in the fluorescence intensity and a shift in the emission wavelength. A detection limit of ∼1.31 ppt and excellent repeatability over 300 cycles are demonstrated, highlighting their high sensitivity and reliability. This work paves the way for a highly sensitive and reliable leak detection system for Li–SOCl2 batteries, enhancing their safety and reliability in various applications.
Fireproof Cavity Structure with Enhanced Impact Resistance and Thermal Insulation toward Safeguarding
Hong Chen - ,
Min Sang *- ,
Yucheng Pan - ,
Shilong Duan - ,
Yuan Hu - , and
Xinglong Gong *
Developing devices emphasizing safety protection is becoming increasingly important due to the widespread occurrence of impact damage and thermal hazards. Herein, the F-SSG/TPU-based circular cavity structure (FC) is developed through a convenient and efficient template method, which can effectively achieve anti-impact and thermal insulation for protection. The flame-retardant shear stiffening gel/thermoplastic urethane (F-SSG/TPU) is synthesized through the dynamic interaction between the SSG, TPU, and modified ammonium polyphosphate (APP@UiO-66-NH2) by thermo-solvent reactions. The developed FC can dissipate the impact force from 4.19 to 0.99 kN at 45 cm impacting heights, indicating good anti-impact performance. Moreover, the thermal insulation test demonstrates that the FC achieves a temperature drop of 76 °C at 160 °C attributed to the unique cavity structure design. Under the continuous shock of high-temperature flame, FC remains intact, and its performance is almost undamaged. These results elaborate that the designed FC can effectively resist various damage, such as high-temperature shock and collision. Then, a wearable wristband integrated with FC is developed which exhibits superior impact resistance and heat insulation properties compared with commercial wristbands. In short, this cavity structure based on high-performance F-SSG/TPU material shows promising potential applications in the protection field.
Degradation Analysis of Exciplex-Based Organic Light-Emitting Devices Using Carbazole-Based Materials
Houssein El Housseiny - ,
Suzanne Fery-Forgues - ,
Marc Ternisien - ,
David Buso - ,
Georges Zissis - , and
Cédric Renaud *
A spectral shift and new emission bands in the green and red regions have been observed in deep blue exciplex-based organic light-emitting diodes (OLEDs) using carbazole-based materials, namely, tris(4-carbazoyl-9-ylphenyl)amine (TCTA). To deeply understand the origin of these new bands, single-layer and bilayer TCTA-based OLEDs subjected to electrical and optical (ultraviolet (UV)) stresses were investigated by using various optical, electrical, morphological, and chemical measurements. The results showed that the stress-induced emission bands primarily originate from morphological changes rather than chemical changes. The accumulation of excitons in the TCTA layer induces molecular aggregation, leading to the formation of electrically active electronic states, namely, electroplexes and electromers, which lead to the appearance of additional emission bands in green and red regions. Impedance spectroscopy measurements on single-layer OLEDs complemented this study. The results showed that TCTA degradation affects charge injection and transport. It was concluded that the stress-induced emission bands are caused by aggregate domain formation and are closely linked to the formation of electrically active defects, which act as trap states for charge carriers in the TCTA band gap.
Unraveling a Molecular Adhesion Mechanism at Complex Polymer–Metal Interfaces
Lukas Kalchgruber - ,
Michael Hahn - ,
Kai A. Schwenzfeier - ,
Martin Rester - ,
Christian Weissensteiner - ,
Laura L. E. Mears *- , and
Markus Valtiner
This publication is Open Access under the license indicated. Learn More
Controlling polymer–metal adhesion is critical in ensuring that materials can be cleanly separated during production processes without residue, which is crucial for various industrial applications. Accurately characterizing adhesion on industrial-grade surfaces is complex due to factors like surface roughness and actual contact area between surfaces and the polymer. In this study, we quantified the adhesive behavior of stainless-steel samples with varying surface treatments against a polymer using the surface forces apparatus (SFA) in reflection geometry, as well as X-ray photoelectron spectroscopy (XPS). We compared adhesive properties with the penetration depth of oxygen and the hydroxide-to-oxide ratio, which were modified by plasma and thermal treatments. Our results indicate that both treatment types enhance the deadhesive properties of the materials compared to native passive films, due to decreasing hydroxide functionality on the surface. Thermal treatment reduces adhesion further, due to an even lower hydroxide content, which reduces hydrogen bonding between the surface and polymer. Furthermore, we show that van der Waals forces, which depend on the density, have marginal to no influence on the adhesive behavior. This study not only advances our understanding of the factors influencing polymer–metal adhesion but also demonstrates the application of the SFA in reflection geometry for characterizing industrially relevant rough surfaces.
Gradient-Wettable Multiwedge Patterned Surface for Effective Transport of Droplets against the Temperature Gradient
Jingjing Zhai - ,
Jie Zhang - ,
Liyuan Xu - ,
Qiankai Liu - ,
Liang Li - ,
Ning He - ,
Shiwei Zhang - , and
Xiuqing Hao *
With the rapid advancement of electronic integration technology, the requirements for the working environment and stability of the heat dissipation equipment have become increasingly stringent. Consequently, studying a high-efficiency gas–liquid two-phase heat transfer surface holds significant importance. Aiming at the limited liquid transport performance caused by the temperature gradient in the heat transfer process, this paper combines the wetting gradient with the shape gradient and proposes a gradient-wettable multiwedge patterned surface, where droplets can be transported over long distances and at high velocities. In this paper, the effect of the average wetting gradient on droplet transport performance is investigated by designing a multiwedge hydrophilic pattern and adjusting the wetting properties of the hydrophobic region. The study focuses on the temperature gradient resistance of gradient-wettable, multiwedge patterned surfaces, providing a mechanistic explanation of the surface’s ability to resist temperature gradients through theoretical analysis. It is shown that the gradient wettability multiwedge patterned surface has better resistance to the temperature gradient that hinders the droplet movement, and the droplets can still achieve transport of ∼38 mm at an average speed of ∼158 mm/s under the temperature gradient of 0.59 °C/mm. The research in this paper provides some insights into the application of temperature gradient resistance on heat transfer surfaces and contributes to heat dissipation methods for electronic integrated environments.
High-Entropy Prussian Blue Analogue Derived Heterostructure Nanoparticles as Bifunctional Oxygen Conversion Electrocatalysts for the Rechargeable Zinc–Air Battery
Wuttichai Tanmathusorachai - ,
Sofiannisa Aulia - ,
Mia Rinawati - ,
Ling-Yu Chang - ,
Chia-Yu Chang - ,
Wei-Hsiang Huang - ,
Ming-Hsien Lin - ,
Wei-Nien Su - ,
Brian Yuliarto - , and
Min-Hsin Yeh *
This publication is Open Access under the license indicated. Learn More
In response to energy challenges, rechargeable zinc–air batteries (RZABs) serve as an ideal platform for energy storage with a high energy density and safety. Nevertheless, addressing the sluggish oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in RZAB requires highly active and robust electrocatalysts. High-entropy Prussian blue analogues (HEPBAs), formed by mixing diverse metals within a single lattice, exhibit enhanced stability due to their increased mixing entropy, which lowers the Gibbs free energy. HEPBAs innately enable sacrificial templating, an effective way to synthesize complex structures. Impressively, in this study, we successfully transform HEPBAs into exquisite multiphase (multimetallic alloy, metal carbide, and metal oxide) heterostructure nanoparticles through a controlled synthesis process. The elusive multiphase heterostructure nanoparticles manifested two active sites for selective ORR and OER. By integrating CNT into HEPBA-derived nanoparticles (HEPBA/CNT-800), the HEPBA/CNT-800 demonstrates superior activity toward both ORR (E1/2 = 0.77 V) in a 0.1 M KOH solution and the OER (η = 330 mV at 50 mA cm–2) in a 1 M KOH solution. The RZAB with a HEPBA/CNT-based air electrode demonstrated an open-circuit voltage of 1.39 V and provided a significant energy density of 71 mW cm–2. Moreover, the charge and discharge cycles lasting up to 40 h at a current density of 5 mA cm–2 demonstrate its excellent stability. This work provides an alternative avenue for the rational design of HEPBA’s derivative for a sustainable rechargeable metal–air battery platform.
Photothermal Induced Dual-Interface: Accelerating Sustainable Hydrogen Evolution from Formic Acid
Kun Liu - and
Yinshi Li *
Formic acid (FA), a liquid hydrogen storage carrier, can release hydrogen via photothermal catalysis, providing a clean and sustainable solution toward a carbon-neutral energy cycle. Despite recent advances in the design of efficient catalysts, the development of advanced systems with high H2 yield, stability, and durability remains challenging due to the inefficient photothermal conversion and mass transfer in the traditional liquid–solid bulk system, as well as the trade-off between hydrogen storage density and dehydrogenation rate. Here, we address these challenges by creating a photothermal-induced dual-interface characterized by high spectral absorption and low heat loss, a facile supply of FA, and vaporization of FA to minimize the energy barrier of the reaction. As a result, a record hydrogen evolution rate (200.9 mmol g–1 h–1) is achieved in a high concentration (26 M) of FA, which is about 15 times higher than the liquid–solid bulk system. In addition, it can be operated continuously for more than 192 h without additive addition and energy consumption, providing a strategy for accelerating interfacial mass transfer to improve catalytic activity, and also presents a reference for sustainable hydrogen production.
Integrating All-rounder TiO2 Accelerated Electrochemiluminescence with Dual-Quenching PDA@COF Probes for Sensitive Quantification and Protein Profiling of Tumorous Exosomes
Haiyang Zhang - ,
Fang Tian - ,
Yang Shi - ,
Xia Zhang - ,
Guocai Zheng - , and
Lingling Li *
Exosomes have been perceived as promising biomarkers for noninvasive cancer diagnosis and treatment monitoring. However, the sensitive and accurate quantification and phenotyping of exosomes remains challenging. Herein, a versatile electrochemiluminescence (ECL) aptasensor was proposed for the sensitive analysis of tumorous exosomes. Specifically, a ternary nanohybrid (Ru-HAuTiO2), by covalently linking ECL luminophore Ru(dcbpy)32+ with gold nanoparticles (AuNPs)-decorated hollow urchin-like TiO2 (HTiO2), was ingeniously designed as a highly luminescent and self-enhanced ECL nanoemitter. Notably, the porous HTiO2 played an “all-rounder” role, including the carrier for ECL luminophores and AuNPs, coreaction accelerator, and specific exosome capturing scaffold through Ti–phosphate coordination interaction. On the other hand, a polydopamine modified covalent organic framework (PDA@COF) was employed as a quencher to remarkably attenuate the ECL of Ru-HAuTiO2 through a dual-quenching mechanism, and further labeled with a specific aptamer (Apt) of exosomal surface protein. Based on forming a Ru-HAuTiO2/exosome/Apt-PDA@COF sandwich structure on the electrode, a “signal on–off” ECL platform for tumorous exosomes was constructed, realizing sensitive detection within the range of 3.1 × 103 particles/mL to 1 × 108 particles/mL and a low limit of detection of 1.41 × 103 particles/mL, achieving phenotypic profiling of surface proteins on different tumorous exosomes. This work provides a promising alternative method for the detection and analysis of exosomes.
Bilirubin-Modified Chondroitin Sulfate-Mediated Multifunctional Liposomes Ameliorate Acute Kidney Injury by Inducing Mitophagy and Regulating Macrophage Polarization
Ziqi Shen - ,
Xiaohua Wang - ,
Li Lu - ,
Runkong Wang - ,
Danni Hu - ,
Ziyan Fan - ,
Liyang Zhu - ,
Ruixue Zhong - ,
Mingquan Wu - ,
Xu Zhou *- , and
Xi Cao *
Acute kidney injury (AKI) is a dynamic process associated with inflammation, oxidative stress, and lipid peroxidation, in which mitochondrial mitophagy and macrophage polarization play a critical role in the pathophysiology. Based on the expression of the CD44 receptor on renal tubular epithelial cells (RTECs) and activated M1 macrophages being abnormally increased, accompanied by up-regulation of reactive oxygen species (ROS) during AKI, the conjugates of bilirubin (BR), an endogenous antioxidant which has the property of anti-inflammation, and chondroitin sulfate (CS) with CD44-targeting property could be a promising therapeutic carrier. In this study, we develop a CD44-targeted/ROS-responsive CS-BR-mediated multifunctional liposome loading celastrol (CS-BR@CLT) for the targeted therapy of AKI. CS-BR@CLT is shown to selectively accumulate in AKI mouse kidneys via targeting of CD44 receptors. Treatment with CS-BR@CLT significantly ameliorates acute kidney injury caused by ischemia-reperfusion and protects renal function. Mechanistically, CS-BR@CLT inhibits apoptosis, protects mitochondria, promotes autophagy, regulates macrophage polarization, and alleviates interstitial inflammation. Overall, our study demonstrates that CS-BR@CLT could be a promising strategy to ameliorate acute kidney injury.
Optimizing Materials to Boost the Valorization of CO2: Tuning Cobalt–Cobalt Interactions on In2O3-Based Photothermal Catalysts
Rocío Sayago-Carro - ,
Irene Barba-Nieto - ,
Natividad Gómez-Cerezo - ,
José A. Rodriguez *- ,
Marcos Fernández-García *- , and
Anna Kubacka *
The valorization of CO2 is an important challenge within the current panorama, since this molecule is probably the main contributor to climate change. In this study, the synthesis of materials based on a nanostructured batonnet-type indium oxide is carried out. In them, different amounts of Co are introduced, varying between 2 and 8% mol. It is verified that the most active sample in the transformation of carbon dioxide to carbon monoxide contains 6 mol %. of Co. This sample’s activity under dual excitation exceeds the thermal counterpart by more than 30%. After carrying out a complete physical and chemical characterization with the help of X-ray absorption spectroscopy and other techniques, it is shown that catalysts with amounts of cobalt equal to or below 4 mol % contain isolated single-atom species, while those with higher amounts of metal display a Co–Co interaction which triggers the evolution of the samples under reaction conditions. The optimum control of this Co–Co interaction and the nature of the final cobalt-containing species determine dual photothermal catalytic properties. This work establishes a structure–activity relationship to interpret the catalytic behavior of highly dispersed subnanometric cobalt species, and thus an avenue to optimize the photothermal valorization of carbon dioxide.
Electrochemical Performance of MoB/Si3N4 Heterojunction as a Potential Anode Material for Li Ion Batteries
Wenbo Zhang - ,
Lingxia Li - ,
Qi Wang - ,
Junqiang Ren - ,
Junchen Li - ,
Xin Guo *- , and
Xuefeng Lu *
In response to the current policy of high storage capacity, two-dimensional (2D) materials have revealed promising prospects as high-performance electrode materials. MoB, as a type of such material, is widely regarded as an anode candidate for Li-ion batteries due to its large specific surface area and abundant ion diffusion channels; the long-term cycling stability, however, is poor owing to material pulverization during the cycle. Therefore, MoB/Si3N4 heterojunction in this work is proposed as an anode material, with Si3N4 acting as a skeleton, maintaining the stability of the structure, while retaining the high energy storage properties of MoB as well. In addition, a certain built-in electric field is formed between them, which can play a role in regulating charge transfer, improving the ion transport channel, and accelerating the migration rate. Herein, the structural, electronic, and electrochemical properties are systematically investigated by first-principles calculations; the final results indicate that the heterojunction anode material does indeed have built-in electric fields, which promote the anode material to possess excellent electrical conductivity and outstanding electrochemical property. Meanwhile, the introduction of vacancy defects can bolster the diffusion kinetic performance of ion transport and greatly reduce the diffusion energy barrier of Li ions, which is conducive to the realization of rapid charge and discharge for the Li ion battery. Based on the synergistic effect of two single-component materials, the synthesized anode material displays a high theoretical capacity of 461 mAh/g, and the calculated open-circuit voltage is 0.66 V, within the range of the negative electrode criterion of 0–1 V, which can effectively play a role in preventing the formation of Li dendrites; these properties are comparable to other 2D anode materials as well. Given these intriguing properties, the MoB/Si3N4 heterojunction is an exceptional candidate for advanced LIB high-performance anode materials.
Performance of Triple-Cation Perovskite Solar Cells under Different Indoor Operating Conditions
Marko Jošt *- ,
Žan Ajdič - , and
Marko Topič
This publication is Open Access under the license indicated. Learn More
We systematically analyze triple-cation perovskite solar cells for indoor applications. A large number of devices with different bandgaps from 1.6 to 1.77 eV were fabricated, and their performance under 1-sun AM1.5 and indoor white light emitting diode (LED) light was compared. We find that the trends agree well with the detailed balance limit; however, the devices near the optimal bandgap (1.77 eV) perform worse due to the lower perovskite quality. Instead, we achieve the highest power conversion efficiency (PCE) of 34.0% under 870 lx with 1.67 eV and Al2O3 passivation. The perovskite with a bandgap of 1.71 eV is not far behind, with a high VOC of 1.02 V. Measurements under different white LED color temperatures confirm that the highest PCE is achieved under the warmest colors. All measurements were carried out in a dedicated indoor setup that ensures the diffuse light typical of indoor environments and allows both short- and long-term measurements. In the best case, we observe no degradation during the 33-day test under simulated office conditions with regular switching on and off of the light and a T80 of 30 days under continuous illumination. The results were obtained from multiple batches, which corroborates our findings and gives them statistical relevance.
Potential-Dependent ATR-SEIRAS and EQCM-D Analysis of Interphase Formation in Zinc Battery Electrolytes
Katherine Betts - ,
Yuhan Jiang - ,
Michael Frailey - ,
Kidus Yohannes - , and
Zhange Feng *
With the heightening interest in bivalent battery technology, there arises a necessity for a thorough investigation into zinc-ion battery (ZIB) electrolytes, accommodating their chemical attributes and potential-dependent structural dynamics. While the phenomenon of in situ solid electrolyte interphase formation is extensively documented in lithium-ion batteries, its analogous occurrences in ZIBs remain limited. Herein is a comparative study of three zinc electrolytes of interest: ZnSO4, ZnOTF, and Zn(TFSI)2/LiTFSI hybrid water-in-salt electrolyte. Additionally, the impact of an acetonitrile additive is scrutinized, with a comparative assessment of the interfacial behavior in aqueous solutions. Utilizing ATR-SEIRAS, potential-dependent alterations in the composition of the electrolyte/electrode interface were monitored, while EQCM-D facilitated a comprehensive understanding of variations in the mass and structural properties of the adsorbed layer. Aqueous ZnSO4 demonstrated the accumulation of porous Zn4SO4(OH)6·xH2O at negative potentials, leading to a mass of 1.47 μg cm–2 after five cycles. Bisulfate formation was observed at positive potentials. SEIRAS measurements for ZnOTF demonstrated reorientation and surface adsorption of CF3SO3– to favor CF3 at the surface for positive potentials, and acetonitrile showed increased stability for the electrode at negative potentials. The additive was also reported to lead to the accumulation of a substantial passivation layer with viscoelastic properties. The zinc water-in-salt showed exceptional surface stability at negative potentials and a widened potential window. A thin rigid zinc SEI layer is reported with a mass of 0.7 μg cm–2. The compositional intricacies of these surface structures are discussed in relation to their solvent conditions. This investigation not only sheds light on the initial charge/discharge cycles in ZIBs but also underscores their pivotal role in instigating enduring transformations that can significantly influence their long-term cycling performance.
Ultra-Stretchable Microfluidic Devices for Optimizing Particle Manipulation in Viscoelastic Fluids
Xiaoyue Kang - ,
Jingtao Ma - ,
Haotian Cha - ,
Helena H.W.B. Hansen - ,
Xiangxun Chen - ,
Hang T. Ta - ,
Fangbao Tian - ,
Nam-Trung Nguyen - ,
Alexander Klimenko - ,
Jun Zhang *- , and
Dan Yuan *
Viscoelastic microfluidics leverages the unique properties of non-Newtonian fluids to manipulate and separate micro- or submicron particles. Channel geometry and dimension are crucial for device performance. Traditional rigid microfluidic devices require numerous iterations of fabrication and testing to optimize these parameters, which is time-consuming and costly. In this work, we developed a flexible microfluidic device using ultra-stretchable and biocompatible Flexdym material to overcome this issue. Our device allows for simultaneous modification of channel dimensions by external stretching. We fabricated a stretchable device with an initial square microchannel (30 μm × 30 μm), and the channel aspect ratio can be adjusted from 1 to 5 by external stretching. Next, the effects of aspect ratio, particle size, flow rate, and poly(ethylene oxide) (PEO) concentration that make the fluid viscoelastic on particle migration were investigated. Finally, we demonstrated the feasibility of our approach by testing channels with an aspect ratio of 3 for the separation of both particles and cells.
Inhibition of Aβ Aggregation and Tau Phosphorylation with Functionalized Biomimetic Nanoparticles for Synergic Alzheimer’s Disease Therapy
Yunfei Tang - ,
Xiaolei Song - ,
Mengmeng Xiao - ,
Chenchen Wang - ,
Xiaowan Zhang - ,
Peng Li - ,
Shihao Sun - ,
Dingzhong Wang - ,
Wei Wei *- , and
Songqin Liu
The main pathological mechanisms of Alzheimer’s Disease (AD) are extracellular senile plaques caused by β-amyloid (Aβ) deposition and intracellular neurofibrillary tangles derived from hyperphosphorylated Tau protein (p-Tau). However, it is difficult to obtain a good curative effect because of the poor brain bioavailability of drugs, which is attributed to the blood-brain barrier (BBB) restriction and complicated brain conditions. Herein, HM-DK was proposed for synergistic therapy of AD by using hollow mesoporous manganese dioxide (HM) as a carrier to deliver an Aβ-inhibiting peptide and a Dp-peptide inhibitor of Tau-related fibril formation synergistically. Inspired by 4T1 cancer cells promoting BBB penetration during brain metastasis, a prospective biomimetic nanocarrier (HM-DK@CM) encapsulated by 4T1 cell membranes was designed. After crossing the BBB, HM-DK@CM inhibited Aβ aggregation and prevented Tau phosphorylation simultaneously. Moreover, by taking advantage of the catalase-like activity of HM, HM-DK@CM relieved oxidative stress and altered the microenvironment associated with the development of AD. Compared with the single therapeutic drug, HM-DK@CM restored nerve damage and improved AD mice’s learning and memory abilities by decreasing Aβ oligomer, p-Tau protein, and inflammation through various pathways for synergistic therapy, which has broad prospects for the effective treatment of AD.
November 3, 2024
Synergistic Suppression of Bipolar Effect and Lattice Thermal Conductivity Leading to High Average Figure of Merit in Bi0.4Sb1.6Te3 Materials through Alloying with AgSbTe2
Xiang Qu - ,
Xiangbin Chen - ,
Tian Yu - ,
Ning Qi *- , and
Zhiquan Chen *
Bismuth telluride-based materials have been widely used in commercial thermoelectric applications due to their excellent thermoelectric performance in the near-room-temperature range, yet further improvement of their thermoelectric properties is still necessary. Moreover, the narrow band gap of these materials results in a bipolar effect at elevated temperatures, which causes severe degradation of the thermoelectric performance. In this work, the commercial Bi0.4Sb1.6Te3 was alloyed with AgSbTe2 by using high-energy ball milling method combined with spark plasma sintering. It was found that ball milling can effectively reduce the lattice thermal conductivity of the samples. The alloying of AgSbTe2 leads to a gradual increase in hole carrier concentration, resulting in an enhanced electrical conductivity and optimized power factor. Additionally, the bipolar effect is also weakened due to the increased hole carrier concentration. Furthermore, the substitution of Ag in the Bi/Sb sublattice causes further reduction in the lattice thermal conductivity. Ultimately, the sample alloyed with 0.15 wt % AgSbTe2 demonstrates its best thermoelectric performance with a maximum zT of 1.35 at 393 K, showing a 20.5% improvement compared to the commercial sample. Besides, its average zT reaches a high value of 1.25 between 303 and 483 K, with a 27.6% improvement compared to that of the commercial sample.
Temperature-Governed Microstructure of Poly(vinyl alcohol) Hydrogels Prepared through Mixed-Solvent-Induced Phase Separation
Huanwei Shen - ,
Min Li - ,
Wei Cui *- , and
Rong Ran *
The formation of phase-separated structures in hydrogels plays a crucial role in determining their optical and mechanical properties. Traditionally, phase-separated hydrogels are prepared through a two-step process involving initial hydrogel synthesis followed by post-treatment. In this study, we present an approach for temperature-governed phase separation microstructure modulation in hydrogels, harnessing the cononsolvency effect. This method allows the phase-separated structure to develop during hydrogel synthesis, significantly simplifying the preparation process. Importantly, we found that the preparation temperature has a substantial effect on the internal structure of the phase-separated hydrogel. We systematically investigated how the temperature influences the phase structure, optical properties, and mechanical performance of these hydrogels. The resulting hydrogels demonstrate excellent moisturizing and antifreezing capabilities. Additionally, the incorporation of sodium chloride imparts remarkable electrical conductivity to the hydrogels, making them suitable for strain sensing applications across a wide temperature range.
Selective Adsorption of Lignin Peroxidase on Lignin for Biocatalytic Conversion of Poplar Wood Biomass to Value-Added Chemicals
Trang Vu Thien Nguyen - ,
Hyeryeong Gye - ,
Heeyeon Baek - ,
Seunghyun Han - , and
Yong Hwan Kim *
Lignin-first biorefineries aim to maximize the valorization of lignin by prioritizing its conversion over other biomass components. This study investigates the selective adsorption of lignin peroxidase (LiP) isozymes from white rot fungi Phanerochaete chrysosporium on lignin, aiming to enhance the biocatalytic conversion of poplar wood biomass into value-added chemicals. The research focuses on the adsorption characteristics of ten recombinant LiP isozymes, particularly PcLiP03, which exhibited the highest adsorption capacity on lignin and negligible adsorption on cellulose. Adsorption isotherms and structural analyses revealed that hydrophobic interactions significantly contribute to the selective adsorption of PcLiP03. Applying PcLiP03 in a continuous stirring cell system effectively converted lignin in unpretreated poplar wood to 2,6-dimethoxy-1,4-benzoquinone under ambient and mild conditions, highlighting its potential for selective lignin depolymerization in integrated biorefineries. This work underscores the importance of enzyme–substrate interactions and offers a promising approach for more efficient and sustainable biomass utilization.
November 2, 2024
Memcapacitors and Memristor Characteristics of ISGE-SOT and SHE-SOT Gain-Driven MoS2:Er Ferromagnets
Haoqun Zeng - ,
Xi Chen - ,
Jianyu Ling - ,
Hongpeng Zhang - ,
Yu Tong - ,
Kewei Zhang *- , and
Mingzhe Zhang
The enhancement of the spin–orbit torque (SOT) effect through the integration of intrinsic inverse spin galvanic effect spin–orbit torque and spin Hall effect spin–orbit torque is fundamentally dependent on the structural and material properties of the ferromagnets. Consequently, the synthesis of ferromagnets with superior structural integrity and material characteristics is of paramount importance. In this study, a gas–liquid chemical reaction, in conjunction with ultrasonic crushing, was employed to synthesize few-layer MoS2:Er nanosheets. X-ray diffraction, X-ray photoelectron spectroscopy, and energy-dispersive spectroscopy analyses confirm the successful substitution of Mo4+ by Er3+ through doping within the MoS2 lattice. Vibrating sample magnetometry and MT measurements indicate that MoS2:Er exhibits room-temperature ferromagnetism (RTFM), with the underlying mechanism elucidated through first-principles calculations. Furthermore, the unique electron density of states at the Fermi level suggests the presence of ferromagnetism in MoS2:Er. A wedge-shaped Pt/MoS2:Er/Au structure was fabricated and subsequently evaluated for current-induced SOT switching, as well as for its memcapacitor and memristor characteristics. The precession of a magnetic moment in three-dimensional space was successfully simulated by solving the Landau–Lifshitz–Gilbert–Slonczewski equation using the Mumax.
Improved Thermal Dissipation in a MoS2 Field-Effect Transistor by Hybrid High-k Dielectric Layers
Jian Huang - ,
Yifan Li - ,
Xiaotong Yu - ,
Zexin Liu - ,
Fanfan Wang - ,
Yue Yue - ,
Rong Zhang - ,
Ruiwen Dai - ,
Kai Yang - ,
Heng Liu - ,
Qingyang Fan - ,
Donghui Hong - ,
Qiang Chen - ,
Zhiqiang Wang - ,
Yuan Gao - , and
Guoqing Xin *
Transition metal dichalcogenides like MoS2 have been considered as crucial channel materials beyond silicon to continuously advance transistor scaling down owing to their two-dimensional structure and exceptional electrical properties. However, the undesirable interface morphology and vibrational phonon frequency mismatch between MoS2 and the dielectric layer induce low thermal boundary conductance, resulting in overheating issues and impeding electrical performance improvement in the MoS2 field-effect transistors. Here, we employed hybrid high-k dielectric layers of Al2O3/HfO2 to simultaneously reduce the interfacial thermal resistance and improve device electrical performance. The enhanced contact, greater vibrational phonon overlapping region, and stronger interfacial bonding force between the top Al2O3 layer and MoS2 promote the heat removal efficiency across the interface to the substrate. Under the same input power density, the temperature profile of the MoS2 transistor on the Al2O3/HfO2 has been largely reduced compared to that of the device on HfO2, with a maximum reduction of 49.5 °C. In addition, the field-effect mobility and current of MoS2 devices on the Al2O3/HfO2 high-k dielectric layers have been significantly improved, attributed to the depressed electron scattering and trap states at the interface. The design of the hybrid high-k dielectric layers provides an efficient solution to simultaneously improve the thermal and electrical performance of the two-dimensional devices.
Heteroatom-Terminated Acrylate-Based Polymer-Dispersed Liquid Crystal Composite Films with High Contrast Ratio and Low Driving Voltage
Chao Chen - ,
Luoning Zhang - ,
Foxin Zhou - ,
Xian He - ,
Zuowei Zhang - ,
Cheng Zou - ,
Jiumei Xiao - ,
Yanzi Gao - ,
Huiyun Wei - ,
Meina Yu *- , and
Huai Yang *
A series of polymer-dispersed liquid crystal (PDLC) films were prepared by using acrylate monomers containing heteroatom-terminated groups. The microscopic morphology and electro-optical properties reveal that these monomers effectively reduce the switching voltage and improve the contrast ratio at the same time. The saturation voltage of the best sample was reduced by 47%, and the contrast ratio was improved by 74%. In addition, the introduction of various heteroatoms endows the PDLC films with a variety of functionalities. Sulfur atoms effectively increase the refractive index of the polymer matrix (np). By adjustment of the match between np and the ordinary refractive index of the LC, films with large contrast ratio and diminutive switching voltage were manufactured for display applications. Besides, chlorine atoms can help reduce the surface anchoring energy of the polymer matrix to LCs and reduce the impedance. Meanwhile, the abundant C–H, C–O, C═O, and C–Cl groups endow the films with solar modulation functions.
In Situ Fabrication of 2D-2D Bi/BiOBr Ohmic Heterojunction for Enhanced Photocatalytic Nitrogen Fixation
Xiaoqi Zheng - ,
Xitong Wang - ,
Liping Feng *- ,
Zhilin Chen - ,
Jiayang Zhang - ,
Xiaodong Zhang - , and
Pengfei Liu
The performance of BiOBr in photocatalytic nitrogen (N2) fixation is suboptimal, attributed to the weak chemisorption and activation of N2 by surface atoms. In our study, we achieved the formation of two-dimensional (2D) bismuth (Bi) on BiOBr nanosheets through in situ annealing in hydrogen atmosphere and successfully constructed a unique 2D-2D Bi/BiOBr ohmic heterojunction using a one-step method. Notably, the Bi/BiOBr heterojunction was utilized for photocatalytic N2 fixation under visible light (λ > 400 nm) in ultrapure water, demonstrating an exceptional N2 fixation rate of 376.16 μmol g–1 h–1. This rate is 7.7 and 4.1 times higher than those of BiOBr and BiOBr-OVs, respectively. The improved photocatalytic efficiency is attributed to the significantly enhanced N2 adsorption capability and more effective separation of photogenerated carriers, both stemming from the distinctive 2D/2D architecture of the Bi/BiOBr heterojunction. This work demonstrates that 2D Bi offers active sites that facilitate photocatalytic N2 fixation and introduces an approach to the design and construction of 2D/2D photocatalysts for applications spanning catalysis, optoelectronics, electronics, and beyond.
Crystal Growth, Characterization, and Properties of Nonlinear Optical Crystals of Li0.5Ag0.5GaTe2 for Mid-Infrared Applications
Guohong Tang - ,
Yuqi He - ,
Hongmei Liao - ,
Shuangqi Zhang - ,
Xiaofei Chu - ,
Rongxia Si - ,
Zhiyuan Jin - ,
Yuhang Du - ,
Chi Wang - ,
Baojun Chen - ,
Zhiyu He - , and
Wei Huang *
LiGaTe2 is a promising nonlinear optical crystal with a large figure of merit (d362/n3), but it is difficult to grow the LiGaTe2 single crystal due to its extreme instability. In this work, we used Ag to replace Li and successfully grew a Li0.5Ag0.5GaTe2 crystal by the modified Bridgman method for the first time. We found it has thermal stability below 200 °C in an atmospheric environment, and the thermal expansion coefficient is positive. This is different from LiGaTe2 and AgGaTe2 which have a negative thermal expansion coefficient along the c-axis. When the temperature exceeds 200 °C, Li0.5Ag0.5GaTe2 is easily decomposed and oxidized. Under closed vacuum conditions, the melting and solidifying points of Li0.5Ag0.5GaTe2 are measured to be 719 and 694 °C. XPS spectra show that the binding energies of Li, Ga, and Te are higher than LiGaTe2, and the surface is easily oxidized. The A1 vibration modes are found at 117.72 and 135.44 cm–1 by the Raman spectrum which is related to the Te and Ga–Te bond in [GaTe4]5– tetrahedra. Li0.5Ag0.5GaTe2 has a wide transmittance range from 0.94 to 20 μm, and there was two-photon absorption near 16 μm. The phonon spectrum and PDOS were simulated by the DFT calculation to study the phonon vibration modes in the lattice, which shows that the density of the Raman vibration is higher than those of AgGaTe2 and LiGaTe2. The SHG test results showed that the SHG response intensity of Li0.5Ag0.5GaTe2 is 1.5 times that of AgGaS2, which shows its excellent nonlinear optical properties for mid-IR applications.
Human Muscle Inspired Anisotropic and Dynamic Metal Ion-Coordinated Mechanically Robust, Stretchable and Swelling-Resistant Hydrogels for Underwater Motion Sensing and Flexible Supercapacitor Application
Ashis Ghosh - ,
Sangita Pandit - ,
Sudhir Kumar - ,
Debabrata Pradhan - , and
Rajat Kumar Das *
Mechanically robust and anisotropic conductive hydrogels have emerged as crucial components in the field of flexible electronic devices, since they possess high mechanical properties and intelligent sensing capabilities. However, the hydrogels often swell on exposure to aqueous medium because of their hydrophilicity, which compromises their mechanical properties. Additionally, the hydrogels’ isotropic polymeric networks demonstrate isotropic ion transport, which significantly diminishes the sensing capabilities of electrical devices based on hydrogels. These factors greatly limit their use in flexible and wearable sensors. In this study, we have developed poly(acrylamide-co-maleic acid-co-butyl acrylate) based anisotropic hydrogels by prestretching and drying, followed by ionic cross-linking to fix the alignment. The anisotropic arrangement of the polymer network resulted in significant improvements in mechanical performance and electrical conductivity along the prestretching direction. This anisotropic hydrogel combines hydrophobic and metal ion-ligand interactions, enhancing the maximum tensile strength up to 11 MPa along the prestretching direction, about 3 times higher than in the perpendicular direction. The optimized 200% prestretched hydrogel exhibited high tensile strength (7 MPa), flexibility (fracture strain 370%), high toughness (16 MJ m–3) and antiswelling behavior in water (equilibrium swelling ratio 2% after 15 days). alongside higher conductivity (3 times higher) and strain sensing ability (4 times higher gauge factor) along the prestretching direction. The hydrogel demonstrated efficient and stable underwater sensing for underwater communication and to monitor human limb position and movement. The anisotropic hydrogel electrolyte-based flexible supercapacitor exhibited 117 Fg–1 specific capacitance at 0.5 Ag–1, and maximum energy density 5.85 Whkg–1, significantly higher than the corresponding values for the isotropic hydrogel-based device (88 F g–1 and 4.4 Whkg–1, respectively). This hydrogel mimics the structural design of unidirectionally oriented muscle fibers, showing better direction dependent functional properties than the corresponding isotropic hydrogel. The anti-swelling ability and retention of mechanical and conductive properties of these hydrogels in aqueous environment suggest long-term usage capability of these functional materials.
Enhancing Water Lubrication in UHMWPE Using Mesoporous Polydopamine Nanoparticles: A Strategy to Mitigate Frictional Vibration
Tun Cai - ,
Conglin Dong *- ,
Chengqing Yuan *- ,
Xiuqin Bai - ,
Dan Jia - ,
Haitao Duan - , and
Zhanmo Zheng
Establishing a persistent lubrication mechanism and a durable tribo-film on contact surfaces is identified as crucial for improving the tribology and vibration characteristics of polymer materials under water-lubricated conditions. This study focuses on enhancing tribological performance and reducing frictional vibrations in ultrahigh molecular weight polyethylene (UHMWPE) through the incorporation of mesoporous polydopamine (MPDA) nanoparticles. In the experiments, MPDA nanoparticles were synthesized and blended with UHMWPE to create UHMWPE/MPDA composites. The interactions between these composites and zirconia (ZrO2) ceramic balls under water lubrication were examined. The results show that when the MPDA content of the composite is 1.5 wt %, the coefficient of friction and wear rate are reduced by 40% and 52% compared with those of pure UHMWPE, respectively. This notable enhancement helped to mitigate friction-induced vibrations, particularly those caused by intermittent sticking and slipping motions. MPDA nanoparticles were shown to act as reservoirs for water, releasing and replenishing water based on the loading conditions, which sustained continuous water-based lubrication at the composite surfaces. Additionally, the surface deformation behavior of the composite material is significantly weakened, which provides a more stable friction surface. This work introduces a novel approach to enhance the interface stability of polymers in water-lubricated environments, offering guidance for developing advanced materials and reducing friction and wear in engineering applications.
November 1, 2024
Lipid Nanoparticle-Mediated Oip5-as1 Delivery Preserves Mitochondrial Function in Myocardial Ischemia/Reperfusion Injury by Inhibiting the p53 Pathway
Xiaowei Niu - ,
Jing Zhang - ,
Jingjing Zhang - ,
Lu Bai - ,
Shuwen Hu - ,
Zheng Zhang - , and
Ming Bai *
Myocardial ischemia/reperfusion (MI/R) injury, a major contributor to poor prognosis in patients with acute myocardial infarction, currently lacks effective therapeutic strategies in clinical practice. The long noncoding RNA (lncRNA) Oip5-as1 can regulate various cellular processes, such as cell proliferation, differentiation, and survival. Oip5-as1 may have potential as a therapeutic target for MI/R injury as its upregulated expression has been associated with reduced infarct size and improved cardiac function in animal models, although how to effectively and safely overexpress Oip5-as1 in vivo remains unclear. Lipid nanoparticles (LNPs) are a versatile technology for targeted drug delivery in numerous therapeutic applications. Herein, we aimed to assess the therapeutic efficacy and safety of LNPs coloaded with Oip5-as1 and a cardiomyocyte-specific binding peptide (LNP@Oip5-as1@CMP) in a murine model of MI/R injury. To achieve this, LNP@Oip5-as1@CMP was synthesized via ethanol injection method. The structural components of LNP@Oip5-as1@CMP were physicochemically analyzed. A hypoxia/reoxygenation (H/R) model in HL-1 cells and coronary artery ligation in mice were used to simulate MI/R injury. Our results demonstrated that LNPs designed for cardiomyocyte targeting and efficient Oip5-as1 delivery were successfully synthesized. In HL-1 cells, LNP@Oip5-as1@CMP treatment significantly reduced mitochondrial apoptosis caused by H/R injury. In the murine MI/R model, the intravenous administration of LNP@Oip5-as1@CMP significantly decreased myocardial infarct size and improved cardiac function. Mechanistic investigations revealed that Oip5-as1 delivery inhibited the p53 signaling pathway. However, the cardioprotective effects of Oip5-as1 were abrogated by administrating Nutlin-3a, a p53 activator. Furthermore, no signs of major organ damage were detected after LNP@Oip5-as1@CMP injection. Our study reveals the therapeutic potential of LNPs for targeted Oip5-as1 delivery in mitigating MI/R injury. These findings pave the way for advanced targeted treatments in cardiovascular diseases, emphasizing the promise of lncRNA-based therapies.
Structurally Colored Photonic Crystal Biomimetic Microstructures for Daytime Radiative Cooling
Lili Yang *- ,
Gang Wang - ,
Shuxian Duan - ,
Jinrui Zhang - , and
Chong Li
Daytime radiative cooling offers a novel solution to the energy crisis, enabling green and efficient thermal management in space. High reflectance in the solar spectrum is essential for passive radiative cooling, rendering dye coloring and similar methods unsuitable for colored coolers. This paper presents a structurally colored photonic crystal biomimetic microstructured radiative cooler. Inspired by natural biological systems, this cooler features a dual-layered microtruncated-cone array structure on the surface and bottom membrane layers. The silver reflector and 3D micrograting surface structure produce continuous iridescent colors through multiple interference effects. Optimized lithographic process enable the fabrication of the ordered dual-layer surface microstructure arrays with precise angular combinations. The dual-layered microtruncated-cone introduces a gradient refractive index, reducing impedance mismatch at the interface. As a result, the radiative cooler achieves high solar spectral reflectance (0.95) and high mid-infrared emissivity (0.95). Notably, the net theoretical cooling power and the subambient temperature drop are 106.9 W m–2 and 7.4 °C, respectively, at an ambient temperature of 40 °C, with a measured average temperature reduction of 6.1 °C under direct sunlight. This performance matches that of advanced radiative coolers, striking a balance between aesthetics and radiative cooling capability.
ZIF-8 Porous Liquids with Different Sterically Hindered Solvents and Porous Guests for Catalytic Conversion of Carbon Dioxide
Jing Zhang - ,
Xiaoqian Li - ,
Fangfang Su - ,
Yangyang Xin - ,
Dechao Wang - ,
Yisong Liu - ,
Dongdong Yao *- , and
Yaping Zheng *
Utilizing carbon dioxide (CO2) as a raw material is an effective way to reduce carbon emissions, and developing catalytic systems with high catalytic activity and stability is crucial for the efficient utilization of CO2. Porous liquids (PLs) with both permanent pores and fluidity have great potential in the fields of catalysis, gas sorption, and storage. Nevertheless, the catalytic performance of PLs is affected by many factors; therefore, further study is needed. Herein, we proposed a general strategy to construct a series of type III PLs with different chemical structures of sterically hindered solvents and different microstructures of porous guests. Benefiting from the unique microstructures, the as-prepared PLs exhibit great potential in catalyzing the reaction of CO2 with propylene oxide under suitable conditions. Moreover, their catalytic activity exceeds that of pure sterically hindered solvents without a porous guest loading. The influences of the nucleophilicity of the anion of the sterically hindered solvent and the microstructure of the porous guests on the catalytic activity and the catalytic stability of the PLs were analyzed. Meanwhile, the mechanism of the catalytic conversion of CO2 was proposed, which is of great significance for the design and development of the subsequent PL catalysts.
Bio-Based Polyurethane Composites with Adjustable Fluorescence and Ultraviolet Shielding for Anti-Counterfeiting and Ultraviolet Protection
Mengyao Zhai - ,
Tao Shou - ,
Dexian Yin - ,
Zhi Chen - ,
Yaowen Wu - ,
Yue Liu - ,
Xiuying Zhao *- ,
Shikai Hu *- , and
Liqun Zhang *
Polyurethane and its composites play an important role in innovative packing materials including anticounterfeiting and ultraviolet protection, however, they are mainly derived from petroleum resources that are not sustainable. In this study, a 100% biobased thermoplastic polyurethane (Bio-TPU) was synthesized using biobased poly(trimethylene ether) glycol, pentamethylene disocyanate, and 1,4-butanediol. Subsequently, biobased tannic acid (TA) was employed to prepare biobased composites. The structures and properties of Bio-TPU and its composites were systematically evaluated. The results showed that the Bio-TPU/TA composite films had excellent and controllable fluorescence and UV-shielding properties. The fluorescence colors of the Bio-TPU/TA composite films could be adjusted to blue, green, and yellow by varying the TA content and adding coupling agents. Moreover, the UV transmittance of the Bio-TPU/TA composites decreased from 79.25 to 5.43% below 400 nm with an increasing TA content, indicating an excellent ultraviolet-barrier performance. Consequently, biobased TPU/TA composite films can be utilized as innovative anticounterfeiting materials and UV-shielding protection films. This study is expected to facilitate sustainable development in the polyurethane industry and broaden the high-end applications of polyurethane such as fashion, electronics, food manufacturing, pharmaceuticals, and finance.
In Situ Nanoconfinement Catalysis for Highly Efficient Redox Transformation
Yuhan Chen - ,
Jisheng Tan - ,
Jingbo Chao - ,
Jingqi Zhang - ,
Yang Tang - ,
Yanping Liu - ,
Qing Hu *- ,
Frederic Coulon - , and
Xiao Jin Yang *
The rapid reduction of Cr(VI) across a wide pH range, from acidic to alkaline pH conditions to stable Cr(III) species for efficient remediation of Cr(VI) pollution, has long been a challenge. Herein, we propose a new concept of in situ nanoconfinement catalysis (iNCC) for highly efficient remediation of Cr(VI) by growing nanosheets of in situ layered double hydroxide (iLDH) on the surface of Al–Mg–Fe alloy achieving chemical reduction rates of >99% in 1 min from pH 3 to 11 for 100 mg L–1 Cr(VI) with a rate constant of 201 h–1. In stark contrast, the reduction rate is less than 6% in 12 h with a rate constant of 0.77 h–1 for the pristine Al–Mg–Fe alloy. The ultrafast reduction of Cr(VI) is most likely attributed to the synergistic catalysis of Al12Mg17 and Al13Fe4 and nanoconfinement of MgAlFe-iLDH and superstable mineralization of Cr(III) by MgAlCrIII- and MgFeCrIII-iLDHs. This study demonstrates the potential of in situ nanoconfinement catalysis on redox transformation for environmental remediation.
Multifunctional Composite Separator Based on NiS2/NiSe2 Homologous Heterostructure Polyhedron Promotes Polysulfide Conversion for High Performance Lithium–Sulfur Batteries
Bo Zhang - ,
Jiaxin Qie - ,
Jiyuan You - ,
Xiaotong Gao - ,
Yuqian Li *- , and
Wenju Wang *
The shuttle effect significantly hinders the industrialization of high-energy-density lithium–sulfur batteries. To address this issue, NiS2/NiSe2 homologous heterostructure polyhedron (HHP) composite separators were developed to immobilize polysulfides and promote their swift conversion. An in-situ visualization symmetrical cell was specifically designed to show the rapid polysulfide adsorption capability of NiS2/NiSe2 HHP, while the electrolyte–separator interfacial contact behavior was simulated to elucidate the mechanism of action of the composite separator in affecting the homogeneous nucleation of lithium metal surfaces. The electrochemical experimental result highlights the substantial enhancement in the reaction kinetics of polysulfides facilitated by NiS2/NiSe2 HHP, owing to its high Li+ diffusion coefficient and Li2S deposition capacity. The NiS2/NiSe2 HHP cells demonstrate high initial specific capacity (1224.1 mAh g–1) at 0.2 C and minimal decay rates (0.073%) at 2 C. The NiS2/NiSe2 HHP separator has high electrochemical catalytic activity with multiple adsorption sites, enabling the rapid polysulfide conversion and contributing to the preparation of high-performance lithium–sulfur batteries.
Influence of Annealing Temperature on the OER Activity of NiO(111) Nanosheets Prepared via Microwave and Solvothermal Synthesis Approaches
Dereje H. Taffa *- ,
Elliot Brim - ,
Konstantin K. Rücker - ,
Darius Hayes - ,
Julian Lorenz *- ,
Omeshwari Bisen - ,
Marcel Risch - ,
Corinna Harms - ,
Ryan M. Richards - , and
Michael Wark
This publication is Open Access under the license indicated. Learn More
Earth-abundant transition metal oxides are promising alternatives to precious metal oxides as electrocatalysts for the oxygen evolution reaction (OER) and are intensively investigated for alkaline water electrolysis. OER electrocatalysis, like most other catalytic reactions, is surface-initiated, and the catalyst performance is fundamentally determined by the surface properties. Most transition metal oxide catalysts show OER activities that depend on the predominantly exposed crystal facets/surface structure. Therefore, the design of synthetic strategies to obtain the most active crystal facets is of significant research interest. In this work, rock salt NiO OER catalysts with (111) predominantly exposed facets were synthesized by a solvothermal (ST) method either heated under supercritical or microwave-assisted (MW) conditions. Particular emphasis was placed on the influence of the post annealing temperature on the structural configuration and OER activity to compare their catalytic performances. The as-prepared electrocatalysts are pure α-Ni hydroxides which were converted to rock salt NiO (111) nanosheets with hexagonal pores after heat treatment at different temperatures. The OER activity of the electrodes has been evaluated in 0.1 M KOH using geometric and intrinsic current densities via normalization by the disk area and BET area, respectively. The lowest overpotential at a geometric current density of 10 mA/cm2 is found for samples pretreated by heating between 400 and 500 °C with a catalyst loading of 115 μg/cm2. Despite the very similar nature of the catalysts obtained from the two methods, the ST electrodes show a higher geometric and intrinsic current density for 500 °C pretreatment. The MW electrodes, however, achieve an optimal geometric current density for 400 °C pretreatment, while their intrinsic current density requires pretreatment over 600 °C. Interestingly, pretreated electrodes show consistently higher OER activity as compared to the poorly crystalline/less ordered hydroxide as-prepared electrocatalysts. Thus, our study highlights the importance of the synthesis method and pretreatment at an optimal temperature.
Sulfonate-Functionalized Metal–Organic Framework as a Porous “Proton Reservoir” for Boosting Electrochemical Reduction of Nitrate to Ammonia
Yun-Shan Tsai - ,
Shang-Cheng Yang - ,
Tzu-Hsien Yang - ,
Chung-Huan Wu - ,
Tzu-Chi Lin - , and
Chung-Wei Kung *
This publication is Open Access under the license indicated. Learn More
The electrochemical reduction reaction of nitrate (NO3RR) is an attractive route to produce ammonia at ambient conditions, but the conversion from nitrate to ammonia, which requires nine protons, has to compete with both the two-proton process of nitrite formation and the hydrogen evolution reaction. Extensive research efforts have thus been made in recent studies to develop electrocatalysts for the NO3RR facilitating the production of ammonia. Rather than designing another better electrocatalyst, herein, we synthesize an electrochemically inactive, porous, and chemically robust zirconium-based metal–organic framework (MOF) with enriched intraframework sulfonate groups, SO3-MOF-808, as a coating deposited on top of the catalytically active copper-based electrode. Although both the overall reaction rate and electrochemically active surface area of the electrode are barely affected by the MOF coating, with negatively charged sulfonate groups capable of enriching more protons near the electrode surface, the MOF coating significantly promotes the selectivity of the NO3RR toward the production of ammonia. In contrast, the use of MOF coating with positively charged trimethylammonium groups to repulse protons strongly facilitates the conversion of nitrate to nitrite, with selectivity of more than 90% at all potentials. Under the optimal operating conditions, the copper electrocatalyst with SO3-MOF-808 coating can achieve a Faradaic efficiency of 87.5% for ammonia production, a nitrate-to-ammonia selectivity of 95.6%, and an ammonia production rate of 97 μmol/cm2 h, outperforming all of those achieved by both the pristine copper (75.0%; 93.9%; 87 μmol/cm2 h) and copper with optimized Nafion coating (83.3%; 86.9%; 64 μmol/cm2 h). Findings here suggest the function of MOF as an advanced alternative to the commercially available Nafion to enrich protons near the surface of electrocatalyst for NO3RR, and shed light on the potential of utilizing such electrochemically inactive MOF coatings in a range of proton-coupled electrocatalytic reactions.
BCP Buffer Layer Enables Efficient and Stable Dopant-Free P3HT Perovskite Solar Cells
Weikui Li - ,
Gang Wang *- ,
Yue Long - ,
Li Xiao - ,
Zhuqiang Zhong - ,
Xiuxian Li - ,
Hang Xu - ,
Hao Yan - , and
Qunliang Song *
Poly(3-hexylthiophene) (P3HT) has garnered significant attention as a novel hole transport material (HTM). Principally, its cost-effective synthesis, excellent hole conductivity, and stable film morphology make it one of the most promising HTMs for perovskite solar cells (PSCs). However, the efficiency of PSCs employing P3HT remains less than ideal, primarily due to the mismatch of energy levels and insufficient interface contact between P3HT and the perovskite film. In this work, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) was inserted into the P3HT/perovskite interface for effectively alleviating the recombination loss. BCP could effectively anchor uncoordinated Pb2+ and establish π–π stacking interactions with P3HT. These interactions not only neutralize flaws to reduce energy depletion but also enhance the configuration of P3HT, aiding in carrier transfer. Consequently, the BCP-modified device achieved an efficiency of 19.27%, which is significantly superior to the control device (12%).
Ultra-Slippery Hydrophilic Surfaces by Hybrid Monolayers
Yuanzhe Li - ,
Yaerim Lee *- ,
Shota Fujikawa - ,
Jiaxing Shen - ,
Shota Sasaki - ,
Masaki Matsuzaki - ,
Norizumi Matsui - ,
Takuro Hosomi - ,
Takeshi Yanagida - , and
Junichiro Shiomi *
This publication is Open Access under the license indicated. Learn More
Slippery solid surfaces with low droplet contact angle hysteresis (CAH) are crucial for applications in thermal management, energy harvesting, and environmental remediation. Traditionally, reducing CAH has been achieved by enhancing surface homogeneity. This work challenges this conventional approach by developing slippery yet hydrophilic surfaces through hybrid monolayers composed of hydrophilic polyethylene glycol (PEG)-silane and hydrophobic alkyl-silane molecules. These hybrid surfaces exhibited exceptionally low CAH (<2°), outperforming well-established homogeneous slippery surfaces. Molecular structural analyses suggested that the remarkable slipperiness is due to a unique spatially staggered molecular configuration, where longer PEG chains shield shorter alkyl chains, thus creating additional free volume while ensuring surface coverage. This was supported by the observation of decreased CAH with increasing temperature, highlighting the role of grafted chain mobility in enhancing slipperiness by self-smoothing and fluid-like behaviors. Furthermore, condensation experiments demonstrated the exceptional performance of the hydrophilic slippery surfaces in dew harvesting due to superior condensation nucleation, droplet coalescence, and self-sweeping efficiency. These findings offer a novel paradigm for designing advanced slippery surfaces and provide valuable insights into the molecular mechanisms governing dynamic wetting.
Electrospun Sulfonated Poly(ether ether ketone) and Chitosan/Poly(vinyl alcohol) Bifunctional Nanofibers to Accelerate Proton Conduction at Subzero Temperature
Shu Hu - ,
Tao Wei - ,
Qingquan Li - ,
Xinna Gao - ,
Niuniu Zhang - ,
Yun Zhao *- , and
Quantong Che *
Multilayered microstructures can accelerate the proton conduction process in proton exchange membranes (PEMs). Herein, we design and construct PEMs with microstructures based on bifunctional nanofibers and sulfonated poly(ether ether ketone) (SPEEK) nanofibers. Specifically, the bifunctional nanofibers composed of poly(vinyl alcohol) and chitosan are prepared and then combined with the electrospun SPEEK nanofibers. The stable microstructure is derived from the compatible interfacial property of nanofibers and the formed hydrogen bonds. The multilayered microstructure consisting of nanofibers accelerates the proton conduction even at subzero temperature because of regulating the proton conduction pathways. Specifically, the (SKNF/CPNF/SKNF)/PA membrane exhibits the proton conductivities of (0.951 ± 0.138) × 10–2 S/cm at −30 °C and (7.32 ± 0.37) × 10–2 S/cm at 160 °C. Additionally, the fine proton conductivity stability is demonstrated by the proton conductivity in the long-term test and the cooling/heating cycle test, such as 1.67 × 10–2 S/cm at −30 °C (after 1000 h), 4.52 × 10–2 S/cm at 30 °C (after 810 h), 1.12 × 10–2 S/cm at −30 °C, and 1.01 × 10–1 S/cm at 30 °C in the cooling/heating process (5 cycles). The single fuel cell possesses an open-circuit voltage of 0.886 V and a peak power density of 0.508 W/cm2 at 130 °C.
La1–xSrxFeO3−δ Perovskite Oxide Nanoparticles for Low-Temperature Aerobic Oxidation of Isobutane to tert-Butyl Alcohol
Masanao Yamamoto - ,
Takeshi Aihara - ,
Keiju Wachi - ,
Michikazu Hara - , and
Keigo Kamata *
This publication is Open Access under the license indicated. Learn More
The development of reusable solid catalysts based on naturally abundant metal elements for the liquid-phase selective oxidation of light alkanes under mild conditions to obtain desired oxygenated products, such as alcohols and carbonyl compounds, remains a challenge. In this study, various perovskite oxide nanoparticles were synthesized by a sol–gel method using aspartic acid, and the effects of A- and B-site metal cations on the liquid-phase oxidation of isobutane to tert-butyl alcohol with molecular oxygen as the sole oxidant were investigated. Iron-based perovskite oxides containing Fe4+ such as BaFeO3−δ, SrFeO3−δ, and La1–xSrxFeO3−δ exhibited catalytic performance superior to those of other Fe3+- and Fe2+-based iron oxides and Mn-, Ni-, and Co-based perovskite oxides. The partial substitution of Sr for La in LaFeO3 significantly enhanced the catalytic performance and durability. In particular, the La0.8Sr0.2FeO3−δ catalyst could be recovered by simple filtration and reused several times without an obvious loss of its high catalytic performance, whereas the recovered BaFeO3−δ and SrFeO3−δ catalysts were almost inactive. La0.8Sr0.2FeO3−δ promoted the selective oxidation of isobutane even under mild conditions (60 °C), and the catalytic activity was comparable to that of homogeneous systems, including halogenated metalloporphyrin complexes. On the basis of mechanistic studies, including the effect of Sr substitution in La1–xSrxFeO3−δ on surface redox reactions, the present oxidation proceeds via a radical-mediated oxidation mechanism, and the surface-mixed Fe3+/Fe4+ valence states of La1–xSrxFeO3−δ nanoparticles likely play an important role in promoting C–H activation of isobutane as well as decomposition of tert-butyl hydroperoxide.
Antidehydration and Stable Mechanical Properties during the Phase Transition of the PNIPAM-Based Hydrogel for Body-Temperature-Monitoring Sensors
Xiaoyong Zhang *- ,
Haoran Ding - ,
Yujia Zhou - ,
Zhaozhao Li - ,
Yongping Bai - , and
Lidong Zhang *
Poly(N-isopropylacrylamide) (PNIPAM) enhances the reversibility and responsiveness of wearable temperature-sensitive devices. However, an open question is whether and how the hydrogel design can prevent adhesive performance loss caused by phase-transition-induced dehydration and unstable mechanical properties between devices and human skin and reduce interfacial failure. Herein, a gelatin-mesh scaffold-based hydrogel (NAGP-Gel) is constructed to inhibit dehydration and volume change, leading to stable mechanical properties, superior adhesiveness, and thermal sensing sensitivity during the phase transition. NAGP-Gel enhances the polymer chains–water interaction and weakens the degree of aggregation of polymer chains–chains, improving antidehydration properties under 45 °C conditions that are higher than the lower critical solution temperature (LCST; i.e., ∼32 °C). The mesh scaffold greatly restricts the phase-transition-induced polymer chain movement and maintains the mechanical performance. In a 60 °C environment, the maximum water loss and volume retention ratio of NAGP-Gel are only 3.58% and 97.3%, respectively. Additionally, NAGP-Gel serves as a temperature sensor, producing a stable thermal–electrical signal within the LCST range. It also can be assembled into an electronic device enabling the transmission of information and recognition of sign language via Morse code. This work broadens the application of PNIPAM in constructing intelligent hydrogels and opens the door to exploring emerging hydrogels for temperature-monitoring applications.
Leather-Based Shoe Soles for Real-Time Gait Recognition and Automatic Remote Assistance Using Machine Learning
Peng Zhang - ,
Xiaomeng Zhang - ,
Ming Teng - ,
Liuying Li - ,
Xudan Liu - ,
Jianyan Feng - ,
Wenjing Wang - ,
Xuechuan Wang - , and
Xiaomin Luo *
Real-time monitoring of gait characteristics is crucial for applications in health monitoring, patient rehabilitation feedback, and telemedicine. However, the effective and stable acquisition and automatic analysis of gait information remain significant challenges. In this study, we present a flexible sensor based on a carbon nanotube/graphene composite conductive leather (CGL), which uses collagen fiber with a three-dimensional network structure as the flexible substrate. The CGL-based sensor demonstrates a high dynamic range, with notable pressure responses ranging from 0.6 to 14.5 kPa and high sensitivity (S = 0.2465 kPa–1). We further developed a device incorporating the CGL-based sensor to collect foot characteristic signals from human motion and designed smart sports shoes to facilitate effective human–computer interaction. Machine learning was employed to collect and process gait characteristic information in various states, including standing, sitting, walking, and falling. For real-time monitoring of falls, we optimized the K-Nearest Time Series Classifier (KNTC) algorithm, achieving an accuracy of 0.99 and a prediction time of only 13 ms, which highlights the system’s excellent intelligent response capabilities. The system maintained a gait recognition accuracy of 90% across diverse populations, with low false-positive (3.3%) and false-negative (3.3%) rates. This work demonstrates stable gait recognition capabilities and provides valuable methods and insights for plantar behavior monitoring and data analysis, contributing to the development of advanced real-time gait monitoring systems.
October 31, 2024
Dry Transfer of van der Waals Junctions of Two-Dimensional Materials onto Patterned Substrates Using Plasticized Poly(vinyl chloride)/Kamaboko-Shaped Polydimethylsiloxane
Momoko Onodera *- ,
Manabu Ataka - ,
Yijin Zhang - ,
Rai Moriya - ,
Kenji Watanabe - ,
Takashi Taniguchi - ,
Hiroshi Toshiyoshi - , and
Tomoki Machida *
This publication is Open Access under the license indicated. Learn More
Two-dimensional (2D) materials can be transferred onto substrates with various surface structures, opening up multiple functions and applications for 2D materials in the form of suspended membranes. In this paper, we present a method for transferring exfoliated 2D crystal flakes from SiO2 substrates onto patterned substrates using a poly(vinyl chloride) (PVC) layer mounted on a polydimethylsiloxane (PDMS) stamp structure. 2D crystal flakes can be transferred onto various patterned structures such as grooves, round holes, and periodic hole or groove patterns. Our method can also be used to fabricate suspended van der Waals (vdW) heterostructures by assembling 2D crystal flakes on the PVC/PDMS stamp and then transferring them onto patterned substrates. The adhesiveness and curvature of the PVC/PDMS stamp were tuned, and a high successful transfer rate was realized due to the use of kamaboko-shaped (semicylindrical) PDMS and the addition of an appropriate amount of a high-viscosity plasticizer to the PVC layer. Taking advantage of this method, we demonstrate the facile fabrication, simply by transferring a vdW heterostructure onto an Au-coated groove substrate, of a suspended vdW field-effect transistor device with the carrier density tuned using ionic gating. This method enables the transfer of 2D crystal flakes and vdW heterostructures onto various patterned substrates, and hence it should help to advance suspended 2D materials research.
Emerging Frontiers in In Situ Forming Hydrogels for Enhanced Hemostasis and Accelerated Wound Healing
Sanchita Sarkhel - and
Amit Jaiswal *
With a surge in the number of accidents and chronic wounds worldwide, there is a growing need for advanced hemostatic and wound care solutions. In this regard, in situ forming hydrogels have emerged as a revolutionary biomaterial due to their inherent properties, which include biocompatibility, biodegradability, porosity, and extracellular matrix (ECM)-like mechanical strength, that render them ideal for biomedical applications. This review demonstrates the advancements of in situ forming hydrogels, tracing their evolution from injectable to more sophisticated forms, such as sprayable and 3-D printed hydrogels. These hydrogels are designed to modulate the pathophysiology of wounds, enhancing hemostasis and facilitating wound repair. The review presents different methodologies for in situ forming hydrogel synthesis, spanning a spectrum of physical and chemical cross-linking techniques. Furthermore, it showcases the adaptability of hydrogels to the dynamic requirements of wound healing processes. Through a detailed discussion, this article sheds light on the multifunctional capabilities of these hydrogels such as their antibacterial, anti-inflammatory, and antioxidant properties. This review aims to inform and inspire continued advancement in the field, ultimately contributing to the development of sophisticated wound care solutions that meet the complexity of clinical needs.
Stromal Reprogramming Optimizes KRAS-Specific Chemotherapy Inducing Antitumor Immunity in Pancreatic Cancer
Qinglian Hu - ,
Jiayu Feng - ,
Lulu Qi - , and
Yuanxiang Jin *
Pancreatic ductal adenocarcinoma (PDAC) is a clinically challenging cancer and is often characterized with rich stroma and mutated KRAS, which determines the tumor microenvironment (TME) and therapy response. Turning immunologically “cold” PDAC into “hot” is an unmet need to improve the therapeutic outcome. Herein, we propose a programmable strategy by sequential delivery of pirfenidone (PFD) and nanoengineered KRAS specific inhibitor (AMG510) and gemcitabine (GEM) liposomes. PFD could achieve precise reduction of the extracellular matrix (ECM) by reprogramming pancreatic stellate cells (PSCs). Subsequently, targeting the KRAS-directed oncogenic signaling pathway effectively inhibited tumor proliferation and migration, which sensitized a chemotherapeutic drug and promoted immunogenic cell death (ICD). In preclinical mouse models of PDAC, PFD mediated stromal modulation enhanced the deep penetration of nanoparticles and improved their subsequent performance in tumor growth inhibition. The molecular mechanisms elucidated that the stroma intervention and KRAS signal pathway regulation reshaped the immunosuppression of PDAC and optimized cytotoxic T-cell-mediated antitumor immunity with sustained antitumor memory. Overall, our study provides a practical strategy with clinical translational promise for immunologically cold tumor PDAC treatment.
Sodium Storage Performance and Mechanism of MnO2 with Different Phase Structures (α, β, γ, δ) as Anode Materials for Sodium-Ion Batteries
Wenhan Xu - ,
Li Jiang - ,
Yanwei Li *- ,
Jing Zhang - ,
Qize Huang - ,
Jinhuan Yao *- ,
Shunhua Xiao *- , and
Chenghong Lei *
An in-depth understanding of the links between the phase structure and electrochemical property is crucial for the advancement of high-performance anode materials. Herein, the sodium storage performance and mechanisms of MnO2 with four distinct phase structures (α, β, γ, and δ) as anodes are systematically investigated. Among the four materials, the layered δ-MnO2 nanoflowers exhibit the best sodium storage performances, characterized by a specific capacity of 303.6 mA h g–1 after 100 cycles at 200 mA g–1, cyclability of 247.3 mA h g–1 after 500 cycles at 1000 mA g–1, and high-rate performance of 184.5 mA h g–1 at 3000 mA g–1. Furthermore, δ-MnO2 shows the most pronounced pseudocapacitance behavior during discharge/charge processes among the four materials. Ex situ XRD and TEM analyses reveal that the sodium storage reactions of α-, β-, and γ-MnO2 proceed via a conversion reaction mechanism, while the sodium storage reaction of δ-MnO2 is controlled by an insertion/deinsertion mechanism. The findings presented in this study may offer insights into the structure regulation and performance promotion of MnO2-based anode materials for SIBs.
Spin-Tunneling Magnetoresistive Effects in Bottom-Up-Grown Ni/Graphene/Ni Nanojunctions
Weicheng Qiu - ,
Fuze Jiang - ,
Junping Peng *- ,
Mengchun Pan - ,
Peisen Li - ,
Jiafei Hu - , and
Yueguo Hu *
Two-dimensional (2D) materials embedded in magnetic tunnel junctions (MTJs) provide a platform to increase the control over spin transport properties by the proximity spin-filtering effect. This could be harnessed to craft spintronic devices with low power consumption and high performance. We explore the spin transport in the 2D MTJs based on graphene, which is uniformly grown on Ni(111) substrates using the chemical vapor deposition technique. After the Ni thin film is deposited bottom–up on the well-grown Ni(111)/graphene surface in an e-beam evaporation system by the physical vapor deposition method, the Ni/graphene/Ni nanojunction array devices are successfully prepared by using nanography technology. Evidence of the emergence of tunneling magnetoresistance (TMR) effects with ultrasmall resistance × area products in graphene-based nanojunctions is observed by the exclusion of anisotropic magnetoresistance. The theoretical analysis shows that this TMR is mainly attributed to the strong spin-filtering effect at the perfect Ni(111)/graphene interface. Besides, earlier findings indicate that the TMR would be promoted more effectively if the short-circuit effect formed in the process of nanographic etching by an ion beam can be further eliminated. Overall, this study provides a path to harness the full potential of graphene-based MTJ array devices with a high efficiency and performance.
Synthesis and Optimization of Foam Copper-Based CoMnOx@Co3O4/CF Catalyst: Achieving Efficient Catalytic Oxidation of Paraxylene
Youxiao Xu - ,
Guangfei Qu *- ,
Huanhuan Wu - ,
Chenyang Zhao - ,
Rui Xu - ,
Ping Ning - , and
Junyan Li
This study successfully developed a foam copper (CF)-based CoMnOx@Co3O4/CF composite catalyst, achieving efficient thermal catalytic oxidation of paraxylene through multifactor optimization of synthesis conditions. At a Co:Mn molar ratio of 2:1 and a calcination temperature of 450 °C, the catalyst exhibited outstanding catalytic performance, with a T90 temperature as low as 246 °C, significantly lower than that of catalysts synthesized under other conditions. Additionally, BET, XPS, Raman, EPR, and H2-TPR test results indicate that the catalyst possesses a high specific surface area, abundant oxygen vacancies, a distribution of multivalent Co and Mn species, and a lower hydrogen reduction temperature, all of which contribute to the high catalytic activity of CoMnOx@Co3O4/CF. Furthermore, in situ DRIFTS confirmed that the oxidation of paraxylene on CoMnOx@Co3O4/CF follows the Mars–Van Krevelen (MvK) mechanism. The proposed reaction pathway begins with the oxidation of the methyl group on paraxylene, followed by the opening of the benzene ring and further oxidation to CO2 and H2O. The innovative structural design and excellent catalytic performance of this catalyst provide new insights and solutions for the industrial treatment of VOCs.
Toward Ultrathin: Advances in Solution-Processed Organic Semiconductor Transistors
Ti Wu - ,
Lin Tan - ,
Yuguang Feng - ,
Luyao Zheng - ,
Yongpeng Li - ,
Shengtao Sun - ,
Shengzhen Liu - ,
Jin Cao - , and
Zhaohui Yu *
In recent years, organic semiconductor (OSC) ultrathin films and their solution-processed organic field-effect transistors (OFETs) have garnered attention for their high flexibility, light weight, solution processability, and tunable optoelectronic properties. These features make them promising candidates for next-generation optoelectronic applications. An ultrathin film typically refers to a film thickness of less than 10 nm, i.e., several molecular layers, which poses challenges for OSC materials and solution-processed methods. In this paper, first we introduce the carrier-transport regulation mechanism under ultrathin limits. Second, we summarize various solution-processed techniques for OSC ultrathin films and elucidate advances in their OFETs performance, such as enhanced or maintained mobilities, improved switching ratios, reduced threshold voltages, and minimized contact resistance. The relationship between the ultrathin-film thickness, microstructure of various OSCs (small molecules and polymers), and device performance is discussed. Third, we explore the recent application of OSC ultrathin-film-based OFETs, such as gas sensors, biosensors, photodetectors, and ferroelectric OFETs (Fe-OFETs). Finally, the conclusion is drawn, and the challenges and prospects of ultrathin OSC transistors are presented. Nowadays, research on ultrathin films is still in its early stages; further experience in precise film deposition control is crucial to advancing research and broadening the scope of applications for OSC ultrathin devices.
A 3D-Printed Bionic Membrane with Autonomously Passive Unidirectional Liquid Transfer Capability for Water Condensation, Collection, and Purification
Sen Meng - ,
Cheng Yao - ,
Gang Liu - ,
Huaifei Chen - ,
Taishan Hu - ,
Zhicheng Zhang *- ,
Jie Yang *- , and
Wei Yang *
Interfacial solar vapor generation is a promising technology for alleviating the current global water crisis, and the evaporation rate and efficiency have approached the theoretical limit. In a practical interfacial evaporation water purification system, the collection rate of purified water is typically lower than the evaporation rate. Passive collection devices based on gravity are susceptible to environmental influences and exhibit low collection efficiency, while active collection devices consuming external energy suffer from complex device systems and extra energy consumption. Given that both collection devices are nonselective and unable to distinguish contaminants mixed in the vapor, bionic membranes with autonomously passive and unidirectional water transfer capacity are developed through 3D printing for efficient water collection. More importantly, the bionic membranes are capable of high-speed water transportation without the need for external energy or gravity drive and liquid-selective transportation for separating oily pollutants from the collected products. The directional transport property facilitates the modular assembly of the bionic membrane, extending its application to practical large-scale solar-driven seawater desalination systems.
Long-Term Stable Eu2O3-Loaded Dendritic Mesoporous Silica Nanoprobes with Coordination-Enhanced Photoluminescence for Ultrasensitive Lateral Flow Immunoassay
Ying Li - ,
Lijun Chen - ,
Ruotong Li - ,
Xinyi Zhao - ,
Mei Shi - ,
Guoqi Zhang *- , and
Fuyou Li *
Inorganic lanthanide nanomaterials as photoluminescent biolabels have attracted increasing attention due to their superior physicochemical properties. However, unstable conjugation of inorganic lanthanide nanomaterials with biological function units (such as antibodies) induces instability of conjugated complexes in aqueous solution, limiting their clinical application. In this study, we developed a rapid point-of-care testing (POCT) platform strategy based on coordination-enhanced time-resolved luminescence of specially nanostructural lanthanide particles for lateral flow immunoassay (CE-TRFIA). This strategy integrates a nanoprobe via a dendritic mesoporous silica nanosphere (DMSN) loading a large amount of ultrasmall amorphous europium oxide (Eu2O3) nanoparticles, which rapidly dissolve to release Eu3+ cations under neutral pH value and form luminescent complexes with photosensitizers (such as β-NTA and TOPO) in an LFIA system. This innovative strategy achieves high-sensitivity detection and long-term stability primarily through high-loading probes, excellent dissolution enhancement, stable covalent coupling, and time-resolved detection. With Procalcitonin (PCT) antigen selected as the detection sample, this approach achieves high-sensitivity detection of PCT with a limit of detection (LoD) as low as 1.9 pg/mL, significantly lower than that of commercial LFIA (0.1 ng/mL), and excellent clinical correlation (r = 0.989). The method offers chemiluminescence-level sensitivity without the need for large instruments while retaining the real-time detection characteristics of LFIA. Our results highlight CE-TRFIA as a highly sensitive, specific, and rapid POCT solution for detecting low-abundance biomarkers such as PCT, enhancing the diagnostic capabilities of traditional LFIA and offering significant potential for ultrasensitive and rapid clinical diagnostics.
Biomimetic Redox Capacitor To Control the Flow of Electrons
Eunkyoung Kim *- ,
Zhiling Zhao - ,
Si Wu - ,
Jinyang Li - ,
William E. Bentley - , and
Gregory F. Payne *
In biological systems, electrons, energy, and information “flow” through the redox modality, and we ask, does biology have redox capacitor capabilities for storing electrons? We describe emerging evidence indicating that biological phenolic/catecholic materials possess such redox capacitor properties. We further describe results that show biomimetic catecholic materials are reversibly redox-active with redox potentials in the midphysiological range and can repeatedly accept electrons (from various reductants), store electrons, and donate electrons (to various oxidants). Importantly, catechol-containing films that are assembled onto electrode surfaces can enhance the flow of electrons, energy, and information. Further, catechol-containing films can serve as redox-based interactive materials capable of actuating biological responses by turning on gene expression from redox-responsive genetic circuits. Looking forward, we envision that the emerging capabilities for measuring dynamic redox processes and reversible redox states will provide new insights into redox biology and will also catalyze new technological opportunities for information processing and energy harvesting.
Photocarrier Dynamics of Two-Dimensional Aza-Fused Covalent Organic Frameworks as Bifunctional Photocatalysts toward Overall Water Splitting
Priya Das - ,
Atish Ghosh - , and
Pranab Sarkar *
Designing high-efficiency bifunctional photocatalysts toward photoinduced overall water splitting is one of the most promising and challenging research directions for clean energy generation. By employing static electronic structure calculation and nonadiabatic molecular dynamics (NAMD) simulation, we herein established a recently synthesized two-dimensional (2D) aza-fused covalent organic framework (aza-COF) as a potential bifunctional photocatalyst toward overall water splitting reactions. Our calculated results reveal that the overpotentials for hydrogen evolution reaction and oxygen evolution reaction are only 0.06 and 0.31 V, respectively, at pH = 4. The dynamics of photoexcited charge carriers studied through NAMD simulation predicts the electron–hole recombination time (25.15 ns), and this confirms that the photogenerated electron and hole carriers migrate to the active sites for the occurrence of reaction before they recombine. Therefore, our results suggest that the 2D aza-COFs exhibit great potential as metal-free and single-material photocatalysts toward overall water splitting under visible light.
Rapid Hemostasis Tumor In Situ Hydrogel Vaccines for Colorectal Cancer Chemo-Immunotherapy
Wenjing Qiu - ,
Yunsheng Zheng - ,
Fei Shen - ,
Zilu Wang - ,
Qing Huang - ,
Wenfeng Guo - ,
Qiang Wang - ,
Ping Yang - ,
Feng He *- ,
Ziyang Cao *- , and
Jie Cao *
Due to the high heterogeneity and the immunosuppressive microenvironment of tumors, most single antigen tumor vaccines often fail to elicit potent antitumor immune responses in clinical trials, resulting in unsatisfactory therapy effects. Hence, personalized tumor vaccines have become a promising modality for cancer immunotherapy. Here, we have developed a tumor in situ hydrogel vaccine (AH/DA-OR) capable of rapid hemostasis for personalized tumor immunotherapy, composed of dopamine-grafted hyaluronic acid (HA/DA) combined with sodium alginate (ALG), with coloaded oxaliplatin (OXA) and resiquimod (R848). The ALG and HA framework imparts excellent biocompatibility to the hydrogel, and dopamine (DA) modification endows it with rapid hemostatic functionality. Following local peritumor injection of AH/DA-OR into the tumor, the in situ hydrogel vaccine achieved the sustained release of the chemotherapeutic agent, OXA, inducing immunogenic cell death in tumor cells and effectively releasing personalized tumor-associated antigens to activate immune responses. Simultaneously, local R848 adjuvant sustained release at the tumor site enhanced immune responses, minimized drug side effects, and amplified immunotherapy effects. Finally, the hydrogel vaccine effectively activated host immune responses to suppress CT26 colorectal cancer growth in vivo, also exhibiting superior inhibition of untreated tumor growth at distant sites. This strategy of rapid hemostasis of tumor in situ hydrogel vaccine holds significant clinical potential and provides a paradigm for achieving secure and robust immunotherapy.
Dynamic Dance of Chirality and Morphology: Interplay of Solvent-Sensitive Self-Assembly in Topological Evolution and Chirality Amplification
Gaurav Kumar - ,
Manoj Kumar - , and
Vandana Bhalla *
The building block Pyra-Chol has been designed and synthesized, which exhibits different achiral morphologies in good solvents, forming nanospheres in THF and nanoflowers in 1,4-dioxane. In the presence of water as a poor cosolvent, Pyra-Chol demonstrates an agnostic behavior, generating left-handed superhelices in the water:THF (80:20) solvent system. However, when the good solvent is switched to 1,4-dioxane, a change in chirality is observed in the water:1,4-dioxane (30:70) solvent system, resulting in the formation of fused nanospheres. Interestingly, when the poor cosolvent is changed from water to MCH in THF, the chiral pattern remains unchanged, but the morphology changes completely. Supported by the collective spectroscopic and microscopic analysis, the present study efficaciously demonstrates the remarkable control of hydrophobic building block over the chiral sense and also highlights the fascinating influence of good as well as poor cosolvent in supporting the distinct molecular packing.
Tailoring Ce-Centered Metal–Organic Frameworks for Fast Li+ Transport in Composite Polymer Electrolyte
Liyuan Wang *- ,
Lingli Dong - ,
Liyuan Xie - ,
Zhitao Wang - ,
Linpo Li - ,
Enbo Shangguan - , and
Jing Li
Regulating metal nodes to innovate the metal–organic framework (MOF) structure is of great interest to boost the performance of MOFs-incorporated composite solid electrolytes. Herein, Ce4+ with a low-lying 4f orbital is selected as metal center to coordinate with organic ligand to prepare MOF of Ce-UiO-66. The unsaturated open metal sites and defected oxygen vacancies furnish Ce-UiO-66 with strengthened Lewis acidity, which promotes Ce-UiO-66 interacting effectively with both poly(ethylene oxide) (PEO) and Li salt anions. Accordingly, Ce-UiO-66 as additive fillers can be uniformly dispersed in PEO matrix to form an advanced composite solid-state electrolyte (Ce-UiO@PEO) with accelerated Li+ transport. The optimized Ce-UiO@PEO displays a boosted ionic conductivity of 4.20 × 10–4 S cm–1 and an improved Li+ transference number of 0.39 at 60 °C, which are highly comparable to those of other MOFs@PEO electrolytes. Combined with the mechanical and thermal stabilities, such a Ce-UiO@PEO electrolyte enables Li/Li symmetric and Li/LiFePO4 full cells with superior cycling stability and rate performance. The Ce-UiO@PEO electrolytes are of great potential to be applied in high-performance lithium metal batteries.
Superflexible Carbon Nanofibers for Multidimensional Complex Deformation Sensing in Soft Robots
Xiangqi Liu - ,
Kunle Li - ,
Dihu Chen - ,
Aixiang Wei - ,
Yu Zhao *- , and
Zhoujun Pang *
Soft robots can make complex motions or deformations due to their infinite freedom, which poses great challenges for monitoring their motion and position. While previous investigations of flexible sensing either focused on stretchable or compression deformations in one or two directions, the complex multidimensional deformations that occur on the surfaces of soft robots have been frequently overlooked. In this work, inspired by spider silk, superflexible carbon nanofibers with a bundled structure were biomimetically designed and fabricated using electrospinning technology and carbonization treatment. The fabricated fibers can be microscopically folded at 180° and can sustain multidimensional shrinkage deformation without microstructural damage during 200,000 times of repeated folding. In addition, the fibers process ultrasmall bending resistance that is two orders of magnitude lower than that of A4 paper and commercial conductive fibers, demonstrating excellent flexibility that is ideal for fabricating sensors in soft robots. Combining the study of origami techniques and mechanical simulations, the bending resistance of the fibers was found to have a step change in response to different deformation angles and radii. As a demonstration, a sensor based on this flexible carbon nanofiber successfully monitors the irregular shrinkage deformation of soft parts, showing great potential in applications of grasping, recognition, and perception. This work sheds light on the design of ultraflexible conductive carbon materials and provides an avenue for the extreme shape-morphing monitoring of soft robots.
Regulating the Twisted Intramolecular Charge Transfer and Anti-heavy Atom Effect at Supramolecular Level for Favorable Photosensitizing Activity in Water
Aditya Singh - ,
Manoj Kumar - , and
Vandana Bhalla *
Photosensitizing assemblies based on twisted intramolecular charge transfer (TICT) active donor–acceptor–donor (D-A-D) system BrTPA-Qx having bromine atoms at the periphery have been developed. Through strategic incorporation of bromine atoms at the para-position to the nitrogen–carbon bonds of phenyl rings at the periphery, halogen–halogen interactions are induced in BrTPA-Qx nanoassemblies in H2O:DMSO (99:1) solution. Hence, the anti-heavy atom effect is induced, and the limitations of TICT (dark excited state) and heavy atom effect (triplet deactivation via radiative decay) could be overcome. Because of TICT and anti-heavy atom effect, supramolecular BrTPA-Qx nanoassemblies demonstrate high efficiency in promoting activation of aerial oxygen via electron and energy transfer pathways in aqueous media. The significant influence of the stabilized TICT state and anti-heavy-atom effect in controlling the ROS generation was validated through in-depth solvent-dependent photophysical studies and investigations of the structure–activity relationship in several model compounds. The notable photosensitizing activity of BrTPA-Qx nanoassemblies is manifested in their ability to efficiently catalyze the oxidative coupling of benzylamine (via type I and type II mechanisms), Knoevenagel condensation of aromatic aldehydes (type II), and oxidative hydroxylation of arylboronic acids (type I) under mild conditions.
Au Nanoparticles-Trisbipyridine Ruthenium(II) Nanoaggregates as Signal-Amplifying SERS Tags for Immunoassay of cTnI
Jiwei Shao - ,
Weiwei Zhang - ,
Yun Huang - ,
Jingcheng Zheng - , and
Yuwu Chi *
Acute myocardial infarction (AMI) is one of the leading causes of human mortality worldwide. In the early stages of AMI, the patient’s electrocardiogram (ECG) may not change, so the fast, sensitive, and accurate detection of the specific biomarker of cardiac troponin I (cTnI) is of great importance in the early diagnosis of AMI. In this work, for the first time, electrostatic nanoaggregates of negatively charged Au nanoparticles and positively charged trisbipyridine ruthenium(II) ions (i.e., (−)AuNPs|[Ru(bpy)3]2+ ENAs) as novel and signal-amplifying surface-enhanced Raman scattering (SERS) tags were synthesized in an easy and rapid (<3 min) way and applied in the highly sensitive, rapid detection of cTnI in human serum by being combined with an immunochromatographic test strip (ICTS). The synthesized (−)AuNPs|[Ru(bpy)3]2+ ENAs exhibited strong SERS activity due to the multiple Raman-active units (three bpy ligands) carried by each [Ru(bpy)3]2+ complex ion and abundant hotspots in each SERS tag. The developed (−)AuNPs|[Ru(bpy)3]2+ ENAs-based SERS-ICTS has been validated to be applicable in detection of cTnI in human serum with excellent sensing performances, such as fast testing (5 min) and a low detection limit (60 pg/mL). It is envisioned that the developed (−)AuNPs|[Ru(bpy)3]2+ ENAs-based SERS-ICTS sensor may have promising applications in point of care testing of various biomarkers in clinic. Additionally, this work may inspire the finding and the application of new types of Raman reporter molecules based on high valent metal-multi ligand coordination compounds like [Ru(bpy)3]2+.
Multifunctional SEBS/AgNWs Nanocomposite Films with Antimicrobial, Antioxidant, and Anti-Inflammatory Properties Promote Infected Wound Healing
Chen Chen - ,
Fructueux Modeste Amona - ,
Junhao Chen - ,
Xiaohan Chen - ,
Yongding Ke - ,
Shuangcheng Tang - ,
Jinming Xu - ,
Xi Chen *- , and
Yipeng Pang *
Wound healing is a complex biological process that can trigger inflammation and oxidative stress and impair myofibrillogenesis and angiogenesis. Several advanced wound-dressing nanocomposite materials have been designed to address these issues. Here, we designed a new multifunctional styrene–ethylene–butylene–styrene/silver nanowire (SEBS/AgNWs)-based nanocomposite film with antimicrobial, antioxidant, and anti-inflammatory properties to promote wound healing. The porous morphological structure of SEBS/AgNWs enhances their antimicrobial, antioxidant, and anti-inflammatory properties. SEBS/AgNWs significantly inhibited the growth of Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, and Escherichia coli strains, effectively wiping out ABTS•+, DPPH•, hydrogen peroxide (H2O2), and hydroxyl (•OH) radicals, showing their effective ROS-scavenging properties. It further showed significant antioxidant properties by increasing the levels of enzyme-like catalase (CAT), superoxide dismutase (SOD), and glutathione (GSH), while decreasing malonaldehyde (MDA) levels. Additionally, SEBS/AgNWs reduced the expression of interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α), while increasing levels of transforming growth factor- β (TGF-β), vascular endothelial growth factor-A (VEGF), and CD31 in wound healing. This suggests that applying a multifunctional nanoplatform based on SEBS/AgNWs could enhance wound healing and improve patient outcomes in wound care management.
All-in-One Magneto-optical Memory Arrays Based on a Two-Dimensional Ferromagnetic Metal
Qinghua Hao - ,
Menghao Cai - ,
Hongwei Dai - ,
Yuntong Xing - ,
Hongjing Chen - ,
Aoyu Zhang - ,
Longde Li - ,
Zhanhong Chenwen - ,
Xia Wang *- , and
Jun-Bo Han *
Two-dimensional (2D) van der Waals (vdW) magnetic materials with atomic-scale thickness and smooth interfaces promise the possibility of developing high-density, energy-efficient spintronic devices. However, it remains a challenge to effectively control the perpendicular magnetic anisotropy (PMA) of 2D vdW ferromagnetic materials, as well as the integration of multiple memory cells. Here, we report highly efficient magneto-optical memory arrays by utilizing the huge spin–orbit torques (SOT) induced by the in-plane current in Fe3GeTe2 (FGT) flake. The device is constructed from individual FGT flakes without heavy metal assistance and allows for a low current density. The magneto-optical memory arrays implement nonvolatile memories for three bits and can be repeatedly scrubbed for “writing” and “reading”. Besides, we show that FGT nanoflakes possess current-controlled volatile switching behavior at zero magnetic field. These results provide a solution for the next generation of all-vdW-scalable, high-performance spintronic logic devices and SOT-Magnetic Random Access Memory (MRAM).
Ionic Liquid-Assisted Strategy for Morphology Engineering of Inorganic Cesium-Based Perovskite Thin Films Toward High-Performance Solar Cells
Gulzhan Zhumadil - ,
Menghua Cao - ,
Yu Han - ,
Vladimir Pavlenko - ,
Gaukhar Nigmetova - ,
Zhuldyz Yelzhanova - ,
Hryhorii P. Parkhomenko - ,
Zhazira Ergasheva - ,
Damir Aidarkhanov - ,
Mannix P. Balanay - ,
Askhat N. Jumabekov - ,
Gang Li *- ,
Zhiwei Ren *- , and
Annie Ng *
The wide bandgap CsPbI2Br perovskite materials have attracted significant attention due to their high thermal stability and compatibility with narrow bandgap materials in tandem devices. The performance of perovskite solar cells (PSCs) is highly dependent on the quality of the perovskite layer, which is governed by the crystallization process during solution processing. However, the crystallization dynamics of CsPbI2Br thin films remain less explored compared to conventional organic–inorganic perovskites. Achieving high-quality CsPbI2Br films with uniform morphology and large perovskite grains remains challenging with standard solution techniques. This study applies the ionic liquid (IL) [EMIM]+[PF6]− as an additive within the bulk CsPbI2Br absorber layer. Within our experimental regime, [EMIM]+[PF6]− accelerates the crystallization process while promoting the formation of large perovskite grains, a feature not commonly observed in previous studies. Our experimental results suggest that the IL acts as heterogeneous nucleation sites, and varying IL incorporation amount significantly impacts the morphology of CsPbI2Br perovskite films. Consistent UV–vis and photoluminescence (PL) red-shifts are observed in the IL-incorporated CsPbI2Br films, with X-ray diffraction (XRD) data projecting an influence on the perovskite crystal structure. These findings provide new insights into the role of ILs in controlling crystallization and morphology that have been minimally discussed in the literature. The incorporation of an optimized amount of [EMIM]+[PF6]− promotes the formation of highly crystalline perovskite thin films with excellent morphology, reducing defect density, enhancing carrier transport, and yielding large grain sizes. As a result, PSCs fabricated with [EMIM]+[PF6]− achieved a power conversion efficiency (PCE) of 17.11% (stabilized at 15.87%) and an open-circuit voltage (VOC) of 1.39 V, along with improved stability compared to control devices. This work provides a straightforward approach for producing high-quality CsPbI2Br thin films with high reproducibility, contributing valuable advancements to Cs-based PSCs.
An Integrated Approach to Elucidate the Interplay between Iron Uptake Dynamics and Magnetosome Formation at the Single-Cell Level in Magnetospirillum gryphiswaldense
Marta Masó-Martínez - ,
Josh Bond - ,
Chidinma A Okolo - ,
Archana C Jadhav - ,
Maria Harkiolaki - ,
Paul D Topham - , and
Alfred Fernández-Castané *
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Iron is a crucial element integral to various fundamental biological molecular mechanisms, including magnetosome biogenesis in magnetotactic bacteria (MTB). Magnetosomes are formed through the internalization and biomineralization of iron into magnetite crystals. However, the interconnected mechanisms by which MTB uptake and regulate intracellular iron for magnetosome biomineralization remain poorly understood, particularly at the single-cell level. To gain insights we employed a holistic multiscale approach, i.e., from elemental iron species to bacterial populations, to elucidate the interplay between iron uptake dynamics and magnetosome formation in Magnetospirillum gryphiswaldense MSR-1 under near-native conditions. We combined a correlative microscopy approach integrating light and X-ray tomography with analytical techniques, such as flow cytometry and inductively coupled plasma spectroscopy, to evaluate the effects of iron and oxygen availability on cellular growth, magnetosome biogenesis, and intracellular iron pool in MSR-1. Our results revealed that increased iron availability under microaerobic conditions significantly promoted the formation of longer magnetosome chains and increased intracellular iron uptake, with a saturation point at 300 μM iron citrate. Beyond this threshold, additional iron did not further extend the magnetosome chain length or increase total intracellular iron levels. Moreover, our work reveals (i) a direct correlation between the labile Fe2+ pool size and magnetosome content, with higher intracellular iron concentrations correlating with increased magnetosome production, and (ii) the existence of an intracellular iron pool, distinct from magnetite, persisting during all stages of biomineralization. This study offers insights into iron dynamics in magnetosome biomineralization at a single-cell level, potentially enhancing the industrial biomanufacturing of magnetosomes.
Deformation Behavior of Microparticle-Based Polymer Films Visualized by AFM Equipped with a Stretching Device
Yuichiro Nishizawa *- ,
Masataka Uchida - ,
Natsuki Watanabe - ,
Feng-Yueh Chan - ,
Christian Ganser - ,
Takeshi Kawasaki - ,
Yuma Sasaki - ,
Daisuke Suzuki - , and
Takayuki Uchihashi *
Understanding the structural changes and property alterations at the nanoscale and microscopic levels is critical to clarifying the deformation behavior and mechanical properties of polymer materials. Especially, in latex films composed of polymer nanoparticles, it is widely accepted that the remaining interfaces between microparticles in the film affect their brittleness. However, detailed information on nanoscale changes of latex films during deformation remains unclear due to technical difficulties in analyzing the microstructures under mechanical stress. In this study, we employed atomic force microscopy equipped with a uniaxial stretching device to visualize the surface structures of films composed of slightly cross-linked microparticles under elongation strain. The observations revealed that the latex film deforms in a nonaffine manner, which is attributed to the concurrent deformation of individual microparticles and the pull-out of interpenetration between them. Furthermore, by introducing a load–strain measurement mechanism to the stretching device, we compared the relationships between nanostructural changes, local property changes, and macroscopic deformation of microparticle-based films. The results suggest that loads are dominated by the deformation of microparticles and dissipate as the interpenetration of surface polymer chains between microparticles is pulled out.
Ion-Mediated Molecular Bridging at Buried Interface Enhances Perovskite Solar Cell Durability
Pengzhen Zhao - ,
Chong Liu - ,
Zhiyu Fang - ,
Riming Sun - ,
Jiahao Wu - ,
Wenhao Zhao - ,
Qian Ye - ,
Pengfei Guo *- , and
Hongqiang Wang *
Engineering heterointerfaces via molecular bridging has been crucial for achieving perovskite solar cells (PSCs) featuring optimal power conversion efficiencies (PCEs) and environmental durability. However, the challenge remains in ensuring interfacial mechanical reliability to enhance the long-term durability of PSCs. Herein, an ion-mediated molecular bridging strategy is intentionally exploited to improve the mechanical integrity between the perovskite bottom and electron-transport layers (ETLs) through balancing interfacial toughness and strength. As a demonstration of the concept, a zwitterionic guanylurea phosphate additive is preburied onto the SnO2 ETL, in which the guanylurea with bifacial NH2 groups servers as a molecular bridge connecting the perovskite and ETL through electrostatic coupling, while the phosphate can interact with charged species at the heterointerface to strengthen the mechanical contact. Benefiting from the robust heterointerfaces, the mechanical durability of flexible PSCs is significantly enhanced, retaining 91.3% of the original efficiency following 6000 bending cycles (bending radius = 3 mm). Additionally, the enhanced mechanical integrity at the buried interface also benefits the charge transfer and chemical stability in rigid PSCs, contributing to PCEs of over 25% as well as thermal stability with T86 of 1200 h under aging at 85 °C.
Porous PDMS–ZnO Wearable Gas Sensor for Acetone Biomarker Detection and Breath Analysis
Yanru Chen - ,
Yixin Liu - ,
Jiaqi Liu - ,
Yuzhen Li - ,
Yuhan Liu - ,
Wenjie Zhang - ,
Liuyang Han - ,
Dongkai Wang - ,
Shuhong Cao - ,
Hanxiao Liu - ,
Qisen Xie - ,
Xiaohao Wang - , and
Min Zhang *
In response to the growing demand for global health monitoring, we report a nonintrusive health detection method using a compact, conformal wearable ultraviolet (UV)-assisted gas-sensing system based on an intrinsically flexible porous polydimethylsiloxane (PDMS)-zinc oxide (ZnO) composite layer (PPZL) for the breath acetone (BrAce) detection and breath event analysis. The enhanced acetone response is attributed to the synergistic effect of UV irradiation and the high surface area of the porous structure, which also improves the mechanical robustness. The UV-assisted wearable sensor reliably detects acetone concentrations ranging from 1 to 100 ppm at room temperature under 4.05 mW/cm2 UV intensity, even under mechanical strains such as a bending radius of 5 mm and 60% tensile strain. It accurately analyzes different breathing patterns (12–20 breaths per minute) and BrAce concentrations, maintaining a stable performance over 20 days with less than 5% signal degradation. The sensor exhibits response and recovery times of average 110–150 and 130–180 s, respectively, and maintains a consistent 3 ppm BrAce response under varying humidity levels up to 70% relative humidity, ensuring accurate detection of BrAce concentrations during real-world breath tests. Additionally, the sensor targets only specific gases, and the sensor’s selectivity is not a key concern. This flexible acetone gas sensor offers a portable solution for health management and a fabrication method for designing flexible metal oxide materials.
Correction to “Conjugated Coordination Porphyrin-based Nanozymes for Photo-/Sono-Augmented Biocatalytic and Homologous Tumor Treatments”
Fangxue Du - ,
Luchang Liu - ,
Ling Li - ,
Jianbo Huang - ,
Liyun Wang - ,
Yuanjiao Tang - ,
Bowen Ke - ,
Li Song - ,
Chong Cheng - ,
Lang Ma *- , and
Li Qiu *
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Nanozymes as Glucose Scavengers and Oxygenerators for Enhancing Tumor Radiotherapy
Yuxuan Zhang - ,
Xingchen Li - ,
Xiaojun Ren - ,
Dongzhou Wang - ,
Yuechen Zhao - ,
Yuan Wang - ,
Shunzi Jin - ,
Quan Lin - ,
Kun Zou *- , and
Tiejun Wang *
Insufficient accumulation of reactive oxygen species (ROS) due to tumor hypoxia significantly contributes to increased radiation resistance and the failure of radiotherapy (RT). Therefore, developing methods to alleviate hypoxia and boost ROS levels represents a promising strategy for enhanced radiosensitivity. This study introduced a self-cascade catalytic Pt@Au nanozymes as a radiosensitizer, using glucose oxidase (GOx)-, catalase (CAT)-, and peroxidase (POD)-like activities to improve hypoxia and increase ROS accumulation, thereby affecting glucose metabolism and enhancing the effects of RT. Pt@Au nanozymes exhibit GOx-like activity, which not only depletes glucose to induce starvation therapy, but also generates hydrogen peroxide (H2O2) for cascade reactions. Moreover, Pt@Au nanozymes demonstrate CAT-like activity, catalyzing the conversion of H2O2 to O2. This conversion effectively alleviates hypoxia, stabilizes ROS, increases DNA damage, significantly enhancing RT efficacy and sustaining the effects of starvation therapy. As high-Z materials, Pt@Au nanozymes can deposit more X-ray energy. Furthermore, the POD-like activity catalyzes the conversion of H2O2 into highly reactive hydroxyl radicals (·OH), which increases ROS levels and enhances RT. Pt@Au nanozymes serve as X-ray computed tomography (CT) imaging agents, allowing for clear differentiation between tumor and normal tissue boundaries and enhancing the precision of RT. In summary, Pt@Au nanozymes serve as effective radiosensitizers by depleting glucose to induce starvation therapy, enhancing cascade reactions, and inhibiting tumor proliferation. Through their self-cascade reactions, these nanozymes dramatically increase oxygen levels within tumors, reduce hypoxia, and enhance ROS levels. This advancement addresses the radioresistance associated with hypoxic tumors, paving the way for innovative strategies in RT.
Correction to “Multifunctional siRNA-Laden Hybrid Nanoplatform for Noninvasive PA/IR Dual-Modal Imaging-Guided Enhanced Photogenetherapy”
Jie Feng - ,
Wenqian Yu - ,
Zhen Xu - ,
Jialing Hu - ,
Jing Liu - , and
Fuan Wang *
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October 30, 2024
Key Sputtering Parameters for Precursor In2O3 Films to Achieve High Carrier Mobility
Junichi Nomoto *- ,
Takashi Koida - ,
Iwao Yamaguchi - , and
Tomohiko Nakajima
Owing to their extremely high carrier mobility (μ) of >100 cm2/(V s) and suitable low carrier concentrations, transparent conducting films of solid-phase crystallized H-doped In2O3 (spc-IO:H) exhibit high conductivity with high optical transparency over a broad frequency range. These properties can be attributed to solid-phase crystallization of the amorphous precursor film. Therefore, the development of high-quality spc-IO:H films requires the deposition conditions of the precursor films to be optimized. This study systematically investigates the effects of three key sputtering parameters, namely, water vapor partial pressure (PH2O), radio frequency magnetron sputtering power (PRF), and flow ratio of O2 to total sputter gas (fO2) on the crystallographic texture evolution of spc-IO:H films during solid-phase crystallization. In addition, the carrier transport in the resulting films is examined. PH2O, PRF, and fO2 are found to be indispensable for producing high-mobility (>100 cm2/(V s)) spc-IO:H films. Furthermore, it is found that introducing a small amount of PH2O during deposition, a lower PRF, and a suitable fO2 facilitates the formation of precursor films having a lower crystallite density. Moreover, after annealing at a temperature of 200 °C, the IO:H precursor films with a lower crystallite density are found to have larger crystal grains. However, the μ values of the postannealed IO:H films are mainly correlated with the stoichiometric deviation.
Boosting Droplet Transport for Fog Harvest
Qianqin Zhang - ,
Siyu Wang - ,
Jinlong Song - , and
Xiaolong Yang *
Wedge-shaped superhydrophilic tracks have been considered as one of the most effective ways to transport droplets for diverse cutting-edge applications, e.g., energy harvesting and lab-on-a-chip devices. Although significant progress, such as serial wedge-shaped tracks with curved edges, has evolved to advance the liquid transport, the ultrafast and long-distance transporting of drop-shaped liquid remains challenging. Here, inspired by the cactus spine that enables fast droplet transport and the serial spindle knot of spider silk, which is capable of collecting condensate from a wide range of distances, we created serial wedge-shaped superhydrophilic patterns and optimized their side edges with a convex brachistochrone curve to boost the acceleration. The junctions of the serial patterns were meanwhile reformed into concave brachistochrone curves to lower the energy barrier for sustained transport. For transporting the liquid in drop shapes to the long distance at high velocity, the wedge-shaped tracks were slenderized to the greatest extent to suppress the liquid spreading and thus prevent the degradation of the Laplace driving force. Moreover, the junction that determines the energy barrier of droplet striding was carefully designed based on the principle of minimizing momentum loss. The exquisite architecture design pushed the droplet transport to a maximum instantaneous velocity of 207.7 mm·s–1 and an outermost transport distance of 120.5 mm, exceeding most wettability or geometric gradient based reports. The transported volume of the droplets can be readily regulated by simply scaling the created architectures. The enhanced droplet transport facilitates the motion and departure of the cohered droplets, enabling a 1.9-fold rise of the water collection rate and 12-fold increase of the heat transfer coefficient during the fog harvest test. This scalable, controllable, and easily fabricatable surface design provides an essential pathway in realizing high-performance manipulation of droplets and possibly pioneers substantial innovative applications in multidisciplinary fields. Those include but are not limited to energy harvesting, lab-on-a-chip devices, and MEMS systems.
Dynamic Rare-Earth Metal–Organic Frameworks Based on Molecular Rotor Linkers with Efficient Emissions and Ultrasensitive Optical Sensing Performance
Yun-Lan Li - ,
Hai-Ling Wang *- ,
Zi-Xin Xiao - ,
Ju-Fen Ai - ,
Fu-Pei Liang *- ,
Zhong-Hong Zhu *- , and
Hua-Hong Zou *
4,4′,4″-Triphenylamine tricarboxylate (TPA-COOH) with a distinct molecular rotor structure was reacted with rare-earth (RE) metal ions to obtain seven dynamic RE-based luminescent MOFs (RE-LMOFs) (i.e., emission colors in the blue, yellow-green, red, and near-infrared regions and emission peak wavelengths between 400 and 1600 nm) via the effective transfer of absorbed energy from TPA-COOH to the RE metal ions through the antenna effect. Due to the large energy level difference between RE ions, it was rare in the early days to use the same ligand to construct energy-level matching RE-LMOF homologues with multiple RE metal centers. The uncoordinated oxygen atoms on the molecular rotor linkers in RE-LMOFs provide active sites that can specifically capture highly toxic metal ions and strong oxidative pollutants. The limit of detection (LOD) of RE-LMOF for Al(III) ions is far below the maximum concentration of Al(III) ions in drinking water stipulated by the U.S. Environmental Protection Agency (USEPA) and that for H2O2 is much lower than the H2O2 content in cancer cells, showing excellent application potential for diagnosing early cell cancelation.
Fluorine-Free Cycloaliphatic Epoxy-Based Siloxane Nanohybrid Binder with High Polar Hydroxyl Group Content Enabling LiFePO4-Type Battery with High Electrochemical Performance and Stability
Uktae Jeong - ,
Junho Jang - ,
Young Geun Hwang - ,
Dong Jun Kang - ,
Min Jeong Kang - ,
Jung-Keun Yoo - ,
Youngseok Oh - ,
Jin Woo Yi - ,
Jihee Yoon *- , and
Hyeon-Gyun Im *
LiFePO4-type (LFP) batteries have attracted significant attention in most battery manufacturing industries due to their long lifespan, high-temperature safety, and low cost of raw materials. However, as an active material, LFP still suffers from several intrinsic drawbacks, including poor conductivity, a low Li+ diffusion coefficient, low capacity, and a lack of electrochemical stability, primarily due to conventional fluorine-based binders. Here, we report a simple yet effective approach to developing a fluorine-free binder based on a robust cycloaliphatic epoxy-based siloxane nanohybrid material (CES) to achieve high electrochemical stability in LFP batteries. The high content of silanol moieties in CES induces a strong affinity for the active material and conductive agent, significantly improving rheological (thixotropy) and mechanical (adhesion and cohesion) properties, which enable the formation of a uniformly coated electrode. As a result, we achieved superior electrochemical performance and stability in CES-applied electrodes compared to those with conventional fluorine-based binders. We investigate the reasons behind the contribution of CES to the electrochemical stability of LFP batteries through various analyses. The high thermal and oxidation stability of CES effectively prevents degradation of LFP-based active materials. Our binder development strategy offers a significant breakthrough in replacing conventional fluorine-based binders, advancing the development of high-performance and stable secondary batteries.
Exploring Selective Fluorescence Turn-On Sensing of Caspase-3 with Molybdenum Disulfide Quenched Copper Nanoclusters: FRET Biosensor
Geneva Indongo - ,
Anju S. Madanan - ,
Susan Varghese - ,
Ali Ibrahim Shkhair - ,
Merin K. Abraham - ,
Greeshma Rajeevan - ,
Arathy B. Kala - , and
Sony George *
Sensing caspase-3 activity is essential for understanding the role of apoptosis in cancer dynamics, controlling therapeutic strategies, and improving patient care in cancer treatment. In this study, we demonstrate a highly sensitive recombinant human caspase-3 (rhC3) detection technique in biological fluids. This technique uses a copper nanocluster stabilized with bovine serum albumin (BSA-CuNCs) as a metal-based fluorescent biosensor, conjugated with anti-human caspase-3 (ahC3). To turn its fluorescence off, molybdenum disulfide nanosheets (MoS2 NSs) are added; this partnership is termed ahC3@BSA-CuNCs/MoS2 nanocouple. In the presence of rhC3, the energy transfer process is affected by strong ahC3/rhC3 interactions. When in close proximity, the rhC3 molecules cause detachment of the nanocluster from the MoS2 NS surface by attracting the ahC3 component of the nanocluster. This increases the distance between the nanocluster and quencher with a consequent restoration of intensity. As the concentration of rhC3 increases, the fluorescence intensity of the system also increases. A proportional response is seen in the concentration between 0.1 and 1.3 ng/mL with a very low limit of detection of 2.75 pg/mL and a quantification limit of 8.60 pg/mL. A simple filter paper strip was made to visually identify the presence of rhC3 under UV light.
Mechanistic Understanding of Long Duration Fast Charge Aqueous Zinc Batteries Using Physically Adsorbed Oligomers as Interphases
Arpita Sharma - ,
Shuo Jin - ,
Yue Deng - ,
Regina Garcia-Mendez - ,
Shifeng Hong - ,
Ankush Mukherjee - ,
Donald L. Koch - , and
Lynden A. Archer *
Polymers have been used as additives in the liquid electrolytes typically used for secondary batteries that utilize metals as anode. Such additives are conventionally argued to improve long-term anode performance by suppressing morphological and hydrodynamic instabilities thought to be responsible for out-of-plane and dendritic metal deposition during battery charging. More recent studies have reported that the polymer additives provide even more fundamental mechanisms for stabilizing metal electrodeposition through their ability to regulate metal electrodeposit crystallography and, thereby, morphology. Few studies explore how polymers carried in a liquid electrolyte achieve these functions, and fewer still provide rules for choosing among the various polymer types, the additive polymer molecular weight (Mw), and concentration in the electrolyte. Here, we investigate how these generally easy-to-control variables influence electrochemical interphase formation inside battery cells and their impact on the morphology and reversibility of Zn electrodes in aqueous electrolytes. We focus on aqueous Zn-iodine electrochemical cells containing linear polyethylene glycol (PEG) chains as additives and find that in electrolytes where the polymer concentration is maintained in the dilute solution regime there is an optimum polymer molecular weight (Mw ≈ 1000 Da), above which beneficial effects of polymers on Zn electrode reversibility and Zn–I2 battery lifetime are progressively lost. By means of optical ellipsometry and theoretical calculations, we show that the optimal Mw is associated with saturation of the thickness of a physiosorbed PEG coating on the Zn metal electrode. Electron microscopy and X-ray photoelectron spectroscopy analysis of Zn electrodeposits formed in such electrolytes reveal that the physiosorbed polymer coating has two primary effects─it regulates the deposit morphology and suppresses parasitic reactions between the electrode and electrolyte components. The parasitic reactions produce species like ZnO, which are known to passivate the Zn electrode and promote nonuniform deposition. Galvanostatic cycling measurements in aqueous Zn–I2 cells containing the PEG additives at the optimal Mw show that the cells maintain very high Coulombic efficiencies (≥99%) at current densities as high as 50 mA/cm2─close to the maximum values permissible across the Celgard separator membranes used in our studies.
Mode-Locked Characteristic of L-Band All-Fiber Laser with Different 2D and Quasi-2D Perovskite Saturable Absorbers
Qixing Yu - ,
Jingzhen Li - ,
Yaoyao Qi *- ,
Ling Zhang *- ,
Zhongan Zhao - ,
Song Yang - ,
Yu Zhang - ,
Zhenxu Bai - ,
Yulei Wang - ,
Zhiwei Lu - ,
Dapeng Yan - , and
Xingwang Zhang
In recent years, the quasi-2D perovskite material ((PEA)2(CsPbBr3)n−1PbBr4) has exhibited outstanding optoelectronic performance and environmental stability due to its unique structure, presenting a broad range of potential applications. However, structural differences arising from varying values of “n” result in distinct nonlinear effects in perovskite materials, which have not been thoroughly investigated to date. We conducted a comparative analysis of the mode-locked characteristics of 2D and n = 3, 4, 5, and 6 quasi-2D perovskite materials within an Erbium-doped fiber laser (EDFL). All materials exhibited excellent saturable absorption effects. Besides, the superior performance of the n = 5 quasi-2D perovskite material, with an SNR of 72.59 dB, performed best in terms of the average power and single pulse energy. The five-layer quasi-2D perovskites offer a suitable bandgap, exciton binding energy, and moderate quantum confinement, leading to effective laser operation. Additionally, the optimal nonlinear absorption, refractive index, and thermal stability contribute to stable and high-power laser performance, while suppressing surface states and interface effects. Experimental results indicate that quasi-2D perovskite materials hold significant potential for applications in the realm of ultrafast optics.
Poly(vinyl alcohol)/Chitosan Hydrogel Containing Gallic Acid-Modified Fe, Cu, and Zn Metal–Organic Frameworks (MOFs): Preparation, Characterization, and Biological Applications
Reza Sacourbaravi - ,
Zeinab Ansari-Asl *- ,
Elham Hoveizi - , and
Esmaeil Darabpour
Hydrogel composites are water-swollen and three-dimensional materials that have been investigated for various biological applications, including controlled drug delivery and tissue engineering, owing to the similarity between their mechanical, electrical, and chemical properties with biological tissues. The hydrogel composites can provide a superior replication of living tissue compared to their single components. In this regard, Fe-BTC, Cu-BTC, and Zn-BTC MOFs were synthesized and modified with gallic acid (GA). The MOFs-based hydrogel composites (M-BTC-GA@PVA-CS) were finally fabricated by freezing–thawing the as-synthesized MOFs, gallic acid, chitosan, and poly(vinyl alcohol) mixture. The obtained hydrogels were characterized using techniques such as FTIR, XRD, UV–vis, SEM, EDS, and TEM. Additionally, their antibacterial activity against E. coli and S. aureus and biocompatibility were investigated. The results showed that the surface modification of M-BTC MOFs with GA improves the antibacterial performance of hydrogels and increases their biocompatibility and cell viability. Among the as-prepared M-BTC MOF-based composites, the Cu-BTC MOF-loaded hydrogels showed the highest antibacterial activity. In contrast, the lowest antibacterial effect was observed for the hydrogels with Fe-BTC MOFs. Furthermore, the H&E staining exhibited improved vascularization in Zn-BTC-GA@PVA-CS and Cu-BTC-GA@PVA-CS scaffolds compared to the Fe-BTC-GA@PVA-CS hydrogel. These MOFs-loaded hydrogels may be suitable for utilization in biological applications such as skin treatment, drug delivery, and cosmetics owing to their excellent antibacterial activity and low cytotoxicity.
Efficient Defect-Driven Cation Exchange beyond the Nanoscale Semiconductors toward Antibacterial Functionalization
Svetlana Polivtseva *- ,
Olga Volobujeva - ,
Ivan Kuznietsov - ,
Reelika Kaupmees - ,
Mati Danilson - ,
Jüri Krustok - ,
Palanivel Molaiyan - ,
Tao Hu - ,
Ulla Lassi - ,
Mihhail Klopov - ,
Heleen van Gog - ,
Marijn A. van Huis - ,
Harleen Kaur - ,
Angela Ivask - ,
Merilin Rosenberg - ,
Nicholas Gathergood - ,
Chaoying Ni - , and
Maarja Grossberg-Kuusk
This publication is Open Access under the license indicated. Learn More
Defect engineering is an exciting tool for customizing semiconductors’ structural and optoelectronic properties. Elaborating programmable methodologies to circumvent energy constraints in multievent inversions expands our understanding of the mechanisms governing the functionalization of nanomaterials. Herein, we introduce a novel strategy based on defect incorporation and solution rationalization, which triggers energetically unfavorable cation exchange reactions in extended solids. Using Sb2X3 + Ag (I) → Ag: Sb2X3 (X= S, Se) as a system to model, we demonstrate that incorporating chalcogen vacancies and AgSbVX complex defects into initial thin films (TFs) is crucial for activating long-range solid-state ion diffusion. Additional regulation of the Lewis acidity of auxiliary chemicals provides an exceptional conversion yield of the Ag precursor into a solid-state product up to 90%, simultaneously transforming upper matrix layers into AgSbX2. The proposed strategy enables tailoring radiative recombination processes, offers efficiency to invert TFs at moderate temperatures quickly, and yields structures of large areas with substantial antibacterial activity in visible light for a particular inversion system. Similar customization can be applied to most sulfides/selenides with controlled reaction yields.
Enhancing Hydrogen Evolution Reaction through the Improved Mass Transfer and Charge Transfer by Bimetal Nodes
Zhihui Li - ,
Xinyu Zhang - ,
Yiran Teng - ,
Hanming Zhang - ,
Tongguang Xu - , and
Fei Teng *
The high cost of hydrogen production by water electrolysis severely challenges its commercial application. It is highly desirable to develop efficient electrocatalysts and innovative electrolytic cells. Introducing additional metal nodes to form bimetallic metal–organic framework (MOF) is a simple, feasible strategy to overcome the poor electrocatalytic performance of single-metal MOF. In this study, the hydrothermal method is used to synthesize bimetallic NixCoy-BTC. It is found that for hydrogen evolution reaction (HER), Ni0.8Co0.2-BTC merely requires a potential of −0.203 V (vs reverse hydrogen electrode, RHE) to achieve 10 mA cm–2, which is significantly lower than that of Ni-BTC (−0.341 V vs RHE). Notably, electrochemical impedance spectroscopy (EIS) and distribution of relaxation time (DRT) analysis indicate that NixCoy-BTC has improved charge transfer and mass transfer process, compared with Ni-BTC. Electron paramagnetic resonance (EPR) confirms that Ni0.8Co0.2-BTC has more unpaired electrons than Ni-BTC. Density functional theory (DFT) calculations show that compared with Ni-BTC, NixCoy-BTC is more thermodynamically favorable for the adsorption of H+, OH–, and H2O. It demonstrates that the change of mass transfer caused by bimetallic nodes and the delicate variation of MOF surface play an important role in the electrochemical process. Moreover, a novel electrolytic cell was developed using a methanol oxidation reaction (MOR) to replace oxygen evolution reaction (OER). In this MOR-based electrolytic cell, a current density of 50 mA cm–2 can be achieved at only a cell voltage of 1.85 V, which is lower than the 2.22 V of OER-based electrolytic cell, suggesting that 16.7% electric energy can be saved. At the same time, the Faraday efficiency (FE, 98.2%) of the MOR-based cell is higher than that (94.5%) of the OER-based cell. This research offers a promising strategy for low-cost hydrogen production.
Effective Antitumor Synergistic Treatment with Fiber-Photothermal Therapy and Heat Shock Protein Inhibitors
Zhuo Zhang - ,
Xu Yue - ,
Ni Lan - ,
Yongkang Zhang - ,
Zesen Li - ,
Fangzhou Jin - ,
Yifei Wang - ,
Bai-Ou Guan - ,
Yang Ran *- , and
Kaisheng Liu *
Effective treatment of malignant tumors remains a thorny issue in current medicine. As a new type of anticancer strategy, photothermal therapy (PTT) has attracted tremendous attention due to its favorable therapeutic effectiveness, high spatial-temporal controllability, and low occurrence of side effects. However, the efficacy of PTT is significantly reduced due to the limited penetration of light and heat-induced overexpression of heat shock protein (Hsp). Herein, we propose an antitumor synergistic therapy that combines fiber-optic PTT and Hsp inhibitors. A rare-earth-doped optical fiber was used as the PTT actuator, and the Hsp inhibitor AT533 was loaded on the fiber surface by use of a hydrogel layer. PTT fibers can be guided to reach tumor lesions directly without being subject to the light penetration limit. The Hsp inhibitor can be released upon the softening of the hydrogel layer under photoheating to deactivate Hsp in the tumor and thus reduce the resistance of the tumor to PTT. This synergistic treatment enhanced the effect of PTT and successfully eradicated tumors in colorectal cancer (CRC) xenograft mouse models, providing a feasible way to realize antitumor and antirecurrence treatment. More importantly, the success of the synergistic treatment of PTT and Hsp inhibition opens new avenues for the development of multimodal and multitype synergistic fiber-optic treatments, which offer pronounced enhancement of therapeutic effectiveness for treating cancer.
Flexible and Extensible Ribbon-Cable Interconnects for Implantable Electrical Neural Interfaces
Negar Geramifard - ,
Mahasty Khajehzadeh - ,
Behnoush Dousti - ,
Justin R. Abbott - ,
Christopher K. Nguyen - ,
Ana G. Hernandez-Reynoso - ,
Alexandra Joshi-Imre - ,
Victor D. Varner - , and
Stuart F. Cogan *
The design and characterization of thin-film ribbon cables as electrical interconnects for implanted neural stimulation and recording devices are reported. Our goal is to develop flexible and extensible ribbon cables that integrate with thin-film, cortical penetrating microelectrode arrays (MEAs). Amorphous silicon carbide (a-SiC) and polyimide were employed as the structural elements of the ribbon cables and multilayer titanium/gold thin films as electrical traces. Using photolithography and thin-film processing, ribbon cables with linear and serpentine electrical traces were investigated. A cable design with an open lattice geometry was also investigated as a means of achieving high levels of extensibility while preserving the electrical function of the cables. Multichannel ribbon cables were fabricated with 50 mm lengths and metallization trace widths of 2–12 μm. The ribbon cables tolerate flexural bending to a radius of 50 μm with no change in trace impedance but tolerate less than 5% tensile elongation without trace failure. Ribbon cables with a lattice structure exhibit 300% elongation without failure. The high elongation tolerance is attributed to a lattice design that results in an out-of-plane displacement that avoids fracture or plastic deformation. Extensible ribbon cables underwent up to 50,000 tensile elongation cycles to 45% extension without failure. An electrical interconnect process using through-holes in the distal gold bond pads of the ribbon cables was used to connect to an a-SiC-based MEA. The electrical connection was created by stenciling a conductive epoxy into the through-holes, bridging metallization between the traces, and MEA. The interconnect was tested using a ribbon cable connected to an a-SiC MEA implanted acutely in rat cortex and used to record neuronal activity. These highly flexible and extensible ribbon cables are expected to accommodate large extensions and facilitate cable routing during surgical implantation. They may also reduce tethering forces on implanted electrode arrays, potentially improving chronic neural recording performance.
Triple-Mode Protection with Ln3+ Ion-Doped Core–Heptad-Shell Single Nanocrystals for High-Level Security Applications
Venkata N. K. B. Adusumalli - ,
Hyeon Jung Yu - ,
Yeongchang Goh - ,
Sang Hwan Nam - , and
Yong Il Park *
In this work, oleic acid (OA)-capped core–heptad-shell (CHS) nanocrystals (NCs) that exhibit multiple emissions achieved through downshifting and orthogonal upconversion are synthesized via layer-by-layer thermal decomposition. This method enables the downshifting process to be accommodated by doping ions in the inert space between two upconversion patterns (the core and fourth shell) and doping Ce/Tb or Ce/Eu ions in the NaGdF4 layer for the first time. These developed CHS NCs exhibit different emission colors via 980 and 800 nm orthogonal upconversion and downshifting emissions under 256 nm UV excitation in hexane solvent. Furthermore, surface-functionalized OA is removed using mild acid treatment. The resulting bare CHS NCs disperse well in water and exhibit 21.60-fold and 43.59-fold higher Ce/Tb and Ce/Eu luminescence intensities, respectively, than the OA-capped CHS NCs. These NCs are mixed with a carboxymethylcellulose (CMC) polymer in an aqueous medium to form a CMC–CHS NC gel. Invisible patterns and QR codes are printed on nonfluorescent paper using gels and screen-printing techniques. These patterns and QR codes exhibit three different emission colors under three different excitations. This method can be used for high-level anticounterfeiting applications.
Computational Exploration of Adsorption-Based Hydrogen Storage in Mg-Alkoxide Functionalized Covalent-Organic Frameworks (COFs): Force-Field and Machine Learning Models
Yu Chen - ,
Guobin Zhao - ,
Sunghyun Yoon - ,
Parsa Habibi - ,
Chang Seop Hong - ,
Song Li - ,
Othonas A. Moultos - ,
Poulumi Dey - ,
Thijs J. H. Vlugt - , and
Yongchul G. Chung *
Hydrogen is a clean-burning fuel that can be converted to other forms. of energy without generating any greenhouse gases. Currently, hydrogen is stored either by compression to high pressure (>700 bar) or cryogenic cooling to liquid form (<23 K). Therefore, it is essential to develop safe, reliable, and energy-efficient storage technology that can store hydrogen at lower pressures and temperatures. In this work, we systematically designed 2902 Mg-alkoxide-functionalized covalent-organic frameworks (COFs) and performed high-throughput (HT) computational screening for hydrogen storage applications at 111, 231, and 296 K. To accurately model the interaction between Mg-alkoxide sites and molecular hydrogen, we performed MP2 calculations to compute the hydrogen binding energy for different types of functionalized models, and the data were subsequently used to fit modified-Morse force field (FF) parameters. Using the developed FF models, we conducted HT grand canonical Monte Carlo (GCMC) simulations to compute hydrogen uptakes for both original and functionalized COFs. The generated data were subsequently used to evaluate the materials’ gravimetric and volumetric storage performance at various temperatures (111, 231, and 296 K). Finally, we developed machine learning (ML) models to predict the hydrogen storage performance of functionalized structures based on the features of the original structures. The developed model showed excellent performance with a mean absolute error (MAE) of 0.061 wt % and 0.456 g/L for predicting the gravimetric and volumetric deliverable capacities, enabling a quick evaluation of structures in a hypothetical COF database. The screening results demonstrated that the Mg-alkoxide functionalization yields greater improvements in volumetric H2 storage capacities for COFs with smaller pores compared to those with larger (mesoporous) pores.
High Mobility, Low Off-Current, and Flexible Fiber-Based a-InGaZnO Thin-Film Transistors toward Wearable Textile OLED Displays
Chan Young Kim - ,
Yong Ha Hwang - ,
Jaehyeock Chang - ,
Seong Uk Kong - ,
Sang-Hee Ko Park - , and
Kyung Cheol Choi *
Fiber-based organic light-emitting diodes (OLEDs) are gaining attention as promising candidates to achieve truly wearable textile displays because of their favorable electrical and mechanical characteristics. However, although fiber OLEDs have been developed into passive-matrix displays, it has not been possible to achieve active OLED operation because of the difficulty of realizing fiber-based thin film transistors (TFTs) with the proper electrical and mechanical performance at the same time. Here, 1D cylindrical fiber-based IGZO TFTs, which simultaneously exhibit a high electrical performance and flexibility, are reported. To address this trade-off relationship, four key stages of a novel fabrication process and unique device structures that suitable for the thermal properties and cylindrical structure of the fiber were applied: (I) prethermal treatment, (II) partially patterned layers, (III) coplanar structure, and (IV) continuous postannealing (CPA) process. As a result, the fabricated fiber-based IGZO TFTs showed high mobility (8.6 cm2/(V s)) and low off-current (∼10–12 A), comparable to that glass-based TFTs, as well as flexibility. Furthermore, based on these valid performances, it was demonstrated that fiber phOLEDs could be driven by fiber-based IGZO TFTs using a wiring connection with Cu wire and Ag paste. The results suggest that this may allow the potential fabrication of fully textile AMOLED displays, integrated with TFTs.
Phase-Changeable Metafabric Enables Dynamic Subambient Humidity and Thermal Regulation
Haiyan Ni - ,
Xuan Zhang - ,
Jianyong Yu - ,
Cunyi Zhao *- , and
Yang Si *
A promising approach to prevent heat- and cold-related illnesses is the integration of zero-energy input control technology into personal thermal management (PTM) systems while reducing energy consumption. However, achieving optimal wearing comfort while maintaining subambient metabolic temperatures using thermally regulating materials without an energy supply remains challenging. In this study, we provide a simple and reliable methodology to produce a phase-changeable metafabric made of thermoplastic polyurethane and phase change capsule (PCC) particles with high moisture permeability and thermal comfort. This approach skillfully incorporates spray-formed PCC particles into a three-dimensional nanofibrous aggregate, forming a stable self-entangled network structure in a single step through simultaneous humidity-assisted electrospraying and electrospinning processes. Additionally, the metafabric demonstrates prominent water resistance and superhydrophobicity, which are attributed to the integration of PCC particles and nanofibers, resulting in the formation of a microporous/nanoporous structure resembling the surface of a lotus leaf. As a result, the phase-changeable metafabric shows an active and passive thermal control performance, with a water vapor transmittance rate of 13.1 kg m–2 d–1 and a phase change enthalpy of 115.05 J g–1 even after 100 thermal cycles. Furthermore, it displays excellent waterproofing capability, characterized by a water contact angle of 158.7° and the ability to withstand a high hydrostatic pressure of 87 kPa. In addition, the metafabric exhibits a good mechanical performance, boasting a tensile strength of 10.5 MPa. Overall, the proposed economical metafabric is an exemplary candidate material for next-generation PTM systems.
Immobilization of Coupled Enzymes onto Metalated Hierarchical Organic Microspheres
Yintao Li - ,
Wei Wang - ,
Yang Sun - ,
Jie Fan - ,
Hua Zhang *- , and
Pengfei Ji *
Hierarchical organic microspheres (HOMs) have emerged as an ideal carrier for immobilizing biomacromolecules. In this research, an in-depth investigation into the structural characteristics of a striated HOM, known as HOM-15, has revealed the assembly mechanism of microspheres through weakly stacked two-dimensional structural units that are composed of V-shaped small organic molecules. With the leverage of this understanding, HOM-15 was adopted as a stable and reusable platform for co-immobilizing of ene-reductases and glucose dehydrogenases via metal ion bridging onto the surface of HOMs. The research demonstrates that metal ion bridging can finely tune the surface properties of HOM-15, thereby facilitating the immobilization of enzymes that would otherwise be impeded by electrostatic repulsion. Comparing HOM-15 to other microspherical variants revealed its superior biocatalytic performance, attributed to the reduction of the mass transfer barrier facilitated by its lamellar-stacking morphology. This novel biocatalytic system underscores the potential applications of HOMs in broader biocatalytic processes.
One-Step Gas Foaming Strategy for Constructing Strontium Nanoparticle Decorated 3D Scaffolds: a New Platform for Repairing Critical Bone Defects
Yujie Chen *- ,
Yucai Li - ,
Xinyi Wang - ,
Xiumei Mo - ,
Yicheng Chen - ,
Zijun Deng - ,
Xiaojian Ye *- , and
Jiangming Yu *
The management of critical-sized bone defects poses significant clinical challenges, particularly in the battlefield and trauma-related injuries. However, bone tissue engineering scaffolds that satisfy high porosity and good angiogenic and osteogenic functions are scarce. In this study, 3D nanofiber scaffolds decorated with strontium nanoparticles (3DS-Sr) were fabricated by combining electrospinning and gas foaming. Sodium borohydride (NaBH4) served a dual role as both a reducing and gas-foaming agent, enabling a one-step process for expansion and modification. In vitro experimental results demonstrated that 3DS-Sr possessed an integrated multilayered porous structure. It promoted angiogenesis by upregulating the expression of hypoxia-inducible factor-1α (HIF-1α) protein and phosphorylation of ERK through the sustained release of Sr2+ and created a favorable microenvironment for osteogenesis by activating the Wnt/β-catenin pathway. In vivo experiments indicated that 3DS-Sr promoted cranial bone regeneration by synergistically promoting the effects of vascularization and osteogenesis. In summary, this study proposed a bioactive bone scaffold in a “one stone, two birds” manner, providing a promising strategy for bone defect repair.
Triphenylene-Based 2D cMOFs: Unraveling the H2S Sensing Mechanism and Applications for a Real-Time Wireless Chemiresistive Sensor
Mingyu Jeon - ,
Joon-Seok Lee - ,
Minhyuk Kim - ,
Jae-Woo Seo - ,
Honghui Kim - ,
Hoi Ri Moon *- ,
Seon-Jin Choi *- , and
Jihan Kim *
Two-dimensional conductive metal–organic frameworks (2D cMOFs) stand at the forefront of chemiresistive sensing innovations due to their high surface areas, distinctive morphologies, and substantial electronic conductivity. Particularly, 2D cMOFs crafted using 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) and 2,3,6,7,10,11-hexaiminotriphenylene (HITP) organic ligands have garnered a large amount of attention due to their designable active sites and proper conductive characteristics. Nevertheless, a deeper exploration into their sensing mechanisms is imperative for a comprehensive understanding of the intrinsic chemistry, which is crucial for the intricate design of specialized 2D cMOF chemiresistive sensors. In this study, we fabricate six M-HXTP (M = Co, Ni, and Cu; X = H and I) chemiresistive sensors, focusing on the application of hydrogen sulfide (H2S) detection. Among these, the 2D cMOFs incorporating Cu metal manifested a remarkably enhanced response to H2S. A combination of experimental and computational studies unveils the mechanisms of sulfur oxidation and Cu reduction, wherein distortion of the reduced MX4 cluster markedly amplifies the sensing response. Lastly, a real-time and portable wireless H2S sensing module has been demonstrated by using the Cu-HHTP composite material, highlighting the substantial practical significance and potential applicability.
Enhancing Stability in All-Vacuum-Evaporated Hybrid Perovskite Solar Cells via a Bipolar Host as a Hole-Transporting Layer
Galing Murokinas - ,
Shu-Jung Hsu - ,
Yi-Sheng Chen - ,
Yu Hsuan Lin - ,
Kuan-Hung Chen - ,
Kasimayan Uma - ,
Jun-Kai Peng - ,
Yuan Jay Chang *- , and
Shun-Wei Liu *
Growing an ultrathin hybrid organic–inorganic perovskite film while maintaining high efficiency and addressing photostability challenges for commercial devices remains a significant hurdle. In this study, we explore the incorporation of organometallic copper phthalocyanine (CuPc) and MS-OC (a previously published spiro-based interfacial material for perovskite solar cells (PSCs), featuring an ortho-oriented carbazole donor) as an addition to the hole-transporting layer (HTL) in all-vacuum-deposited Cs0.06FA0.94Pb(I0.68Br0.32)3 PSCs. By innovatively introducing a 3 nm-thin MS-OC layer at the CuPc-perovskite interface, we achieve a deeper understanding of the crystallographic dynamics of perovskites, resulting in a uniform and pinhole-free film. We demonstrate that PSCs utilizing the CuPc HTL with an MS-OC interfacial layer in a p-i-n architecture achieve a power conversion efficiency (PCE) of up to 14.42%. Remarkably, the CuPc/MS-OC-based device exhibits outstanding long-term photostability, maintaining its initial PCE over 400 h (T100 = 400 h) under continuous sunlight illumination. By configuring the device architecture as ITO/MoO3/CuPc/MS-OC/perovskite/C60/BCP/Ag, we find that the evaporated MS-OC thin films effectively reduce nonradiative losses, passivate the perovskite, and enhance device performance. Our findings indicate that the polarity of the underlying surface significantly influences perovskite nucleation, underscoring the potential to improve photostability by controlling interfacial imperfections.
Crystallization Control to Prepare Uniform CsPbI2Br Thin Films for High-Efficiency Perovskite Solar Cells
Miao He - ,
Chuwu Xing - ,
Qinhui Bao - ,
Linkai Yu - ,
Zhiwei Nie - ,
Rihua Wang - ,
Chunsheng Wan - ,
Duofa Wang *- , and
Tianjin Zhang *
All-inorganic perovskite solar cells (PSCs) face challenges related to film inhomogeneity, which arises from nonideal crystallization. This issue significantly impedes the advancement of all-inorganic PSCs. In this study, we observed that during the crystallization process of CsPbI2Br, the Br-rich intermediate phase is often preferentially deposited, leading to an uneven distribution in the out-of-plane direction of the perovskite film. To address this issue, crown ether molecules (dibenzo-18-crown-6) were introduced into the perovskite precursor solution. The complexation of crown ether with Cs cations and Br anions optimizes the crystallization sequence of the perovskite, ensuring that the intermediate phase closely conforms to the standard stoichiometric ratio. This adjustment significantly mitigates the problem of uneven halogen ion distribution along the out-of-plane direction. Furthermore, the crown ether thermally decomposes during the high-temperature annealing process, thereby not affecting the composition of the final perovskite film. Following crown ether treatment, the efficiency of the PSCs reached 14.08%, and the unpackaged devices maintained 80% of their initial efficiency after 1000 h of exposure to light in an atmospheric environment.
Facile Mechanochemical Functionalization of Hydrophobic Substrates for Single-Walled Carbon Nanotube Based Optical Reporters of Hydrolase Activity
Abbas Elhambakhsh - ,
Mohaddeseh Abbasi - ,
Cole R. Dutter - ,
Marshall D. McDaniel - ,
Brett VanVeller - ,
Andrew C. Hillier - , and
Nigel F. Reuel *
Single walled carbon nanotubes (SWCNT) have recently been demonstrated as modular, near-infrared (nIR) probes for reporting hydrolase activity; however, these have been limited to naturally amphipathic substrate targets used to noncovalently functionalize the hydrophobic nanoparticles. Many relevant substrate targets are hydrophobic (such as recalcitrant biomass) and pose a challenge for modular functionalization. In this work, a facile mechanochemistry approach was used to couple insoluble substrates, such as lignin, to SWCNT using l-lysine amino acid as a linker and tip sonication as the mechanochemical energy source. The proposed coupling mechanism is ion pairing between the lysine amines and lignin carboxylic acids, as evidenced by FTIR, NMR, SEM, and elemental analyses. The limits of detection for the lignin–lysine–SWCNT (LLS) probe were established using commercial enzymes and found to be 0.25 ppm (volume basis) of the formulated product. Real-world use of the LLS probes was shown by evaluating soil hydrolase activities of soil samples gathered from different corn root proximal locations and soil types. Additionally, the probes were used to determine the effect of storage temperature on the measured enzyme response. The modularity of this mechanochemical functionalization approach is demonstrated with other substrates such as zein and 9-anthracenecarboxylic acid, which further corroborate the mechanochemical mechanism.
Tuning Perovskite Nanocrystal Synthesis via Amphiphilic Block Copolymer Templates and Solvent Interactions
Ya-Sen Sun *- ,
Kuan-Wei Wu - , and
Orion Shih
This publication is Open Access under the license indicated. Learn More
Amphiphilic block copolymer (a-BCP) micelles offer morphological diversity and dimensional tunability, making them suitable for the fabrication of perovskite nanocrystals. However, precise control over the nucleation and growth of perovskite nanocrystals using a-BCP colloidal templates remains underexplored. This study investigates the effects of toluene, methanol, and polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) on the formation of cesium lead bromide (CsPbBr3) nanocrystals. The process involves four stages: (i) PS-b-P2VP micellization, (ii) PbBr2 complexation, (iii) coordination interaction with P2VP, and (iv) burst nucleation of CsPbBr3 nanocrystals. Toluene, a good solvent for PS but a nonsolvent for P2VP, PbBr2, and CsBr, facilitates the formation of PS-b-P2VP spherical micelles. Adding PbBr2 to these micelles in toluene results in multiple emulsion, dispersing PbBr2 microstructures (microemulsion) and forming [PbBr3]− complexes encapsulated by the micelles (nanoemulsion). Prolonged stirring enhances this nanoemulsion. CsBr, insoluble in toluene, must be dissolved in methanol before being mixed with micelle-encapsulated complexes, promoting quick crystal nucleation. However, excess methanol weakens micellization, leading to the formation of fused micelles and irregular nanocrystals. At a high methanol content, [PbBr4]2– complexes also form, driving CsPbBr3 to CsPb2Br5 transformation via Ostwald ripening, resulting in large CsPb2Br5 microcrystals that precipitate due to gravitational forces overcoming Brownian motion, destabilizing their dispersion in the solution.
Enhancing Antibacterial Properties of Titanium Implants through Covalent Conjugation of Self-Assembling Fmoc-Phe-Phe Dipeptide on Titania Nanotubes
Ramesh Singh - and
Ketul C. Popat *
This publication is Open Access under the license indicated. Learn More
Bacterial infections and biofilm formation are significant challenges for medical implants. While titanium nanotube engineering improves biocompatibility, it cannot prevent bacterial adhesion and biofilm formation. Optimizing the biomaterial’s surface chemistry is vital for its desired functioning in the biological environment. This study demonstrates the covalent conjugating of the self-assembling dipeptide N-fluorenylmethyloxycarbonyl-diphenylalanine (Fmoc-FF) onto titanium nanotube surfaces (TiNTs) without altering the topography. Fmoc-FF peptides, in conjugation with TiNTs, can inhibit biofilm formation, eradicate pre-existing biofilms, and kill bacteria. This functionalization imparts antibacterial properties to the surface while retaining beneficial nanotube topography, synergistically enhancing bioactivity. Surface characterization by XPS, FT-IR, EDS, and SEM confirmed the successful functionalization. Bacterial adhesion experiments showed a significantly improved antibacterial activity of the functionalized TiNT surfaces. This study opens future possibilities for associating biomedical applications such as cell–cell interactions, tissue engineering, and controlled drug delivery of multifunctional self-assembling short peptides with implant materials through surface functionalization.
Green and Fast Synthesis of NiCo-MOF for Simultaneous Purification–Immobilization of Bienzyme to Catalyze the Synthesis of Ginsenoside Rh2
Junsong Yue - ,
Zhiyan Li - ,
Xiaochen Liu *- ,
Zhansheng Wu *- ,
Jianwen Wang - ,
Min Tu - ,
Huaiqi Shi - ,
Daidi Fan - , and
Yan Li
Traditional metal–organic frameworks (MOFs) preparation is generally time-consuming, polluting, and lacking specificity for enzyme immobilization. This paper introduced a facile, rapid, and green method to produce three MOFs subsequently employed to purify and coimmobilize recombinant glycosyltransferase (UGT) and recombinant sucrose synthetase (SUSy) using histidine tag (His-tag) for the specific adsorption of Ni2+ and Co2+ from MOFs. This method simplified enzyme purification from crude extracts and enabled enzymes to be reused. The results demonstrated that NiCo-MOF exhibited a higher enzyme load (115.9 mg/g) than monometallic MOFs. Additionally, the NiCo-MOF@UGT&SUSy demonstrated excellent stability and efficiently produced the rare ginsenoside Rh2 by catalyzing a coupling reaction (95.6 μg/mL), solving the problem of the substrate cost of uridine diphosphate glucose (UDPG). The NiCo-MOF@UGT&SUSy retained 68.97% of the initial activity after 10 cycles. Finally, molecular docking studies elucidated the conversion mechanism of the target product Rh2. This technique is important in the industrialization of ginsenoside production and enzyme purification.
PEGylated BODIPY Photosensitizer for Type I Dominant Photodynamic Therapy and Afterglow Imaging
Hui Wen - ,
Qihang Wu - ,
Xiujuan Xiang - ,
Tingting Sun *- ,
Zhigang Xie *- , and
Xuesi Chen
Type I photodynamic therapy (PDT) exhibits outstanding therapeutic effects in hypoxic environments in tumors, but the design of type I photosensitizers (PSs), especially those with simple structures but dramatic properties, remains a challenge. Herein, we report a design strategy for developing type I PSs in one molecule with afterglow luminescence. As a proof concept, a 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) PS (BIP) bearing water-soluble poly(ethylene glycol) (mPEG550) chains is synthesized, and BIP can self-assemble into nanoparticles (BIPNs). Interestingly, BIPNs exhibit an O2•--triggered afterglow luminescence, which is scarce, especially for BODIPY derivatives. BIPNs demonstrate outstanding type I dominant PDT at an ultralow dose under both hypoxic and normoxic environments, which can significantly inhibit tumor growth under irradiation. This work highlights a high-performance PS with afterglow luminescence and excellent PDT effects, underscoring the significant potential of versatile PSs in clinical tumor theranostics.
General Approach to Hydrolysis Resistive Aluminum Nitride and Its High-Performance Thermal Interface Materials
Bin Zhang - ,
Zhengli Dou - ,
Rui Yuan - ,
Lu He - ,
Zilong Xie - ,
Chuanlong Li - ,
Yongzheng Zhang *- ,
Qiang Fu - , and
Kai Wu *
Aluminum nitride (AlN), noted for its excellent thermal conductivity and exceptional electrical insulation, presents a promising alternative to traditional ceramic particles in thermal interface materials (TIMs). However, its broader adoption in practical applications is limited by performance degradation due to the vulnerability of its crystal structure to ubiquitous moisture. This study introduces a dual solution, utilizing a mechanochemical method to design a dense outer layer of Galinstan liquid metal (LM) that simultaneously enhances AlN’s resistance to hydrolysis and improves its thermal performance in TIM applications. The high surface free energy of the LM layer imparts hydrophobic properties to the AlN surface and, combined with outer metal oxides, forms a dual-layer protective barrier that prevents water penetration, significantly enhancing the TIM’s long-term stability in high-humidity conditions. Additionally, the LM layer at the interface improves the thixotropic properties of the TIM and enhances interfacial heat transport through the bridging effect of the LM, resulting in improved rheological mobility and thermal conductivity of the composite material. This win–win surface modification strategy opens opportunities for the practical and durable application of AlN in widespread electronic thermal management.
October 29, 2024
Nearly Barrierless Polarization Switching Mechanisms in ZrO2 Having Perpendicular In-Plane Domain Walls
Manifa Noor - ,
Matthew Bergschneider - ,
Jongchan Kim - ,
Nashrah Afroze - ,
Asif Islam Khan - ,
Sou-Chi Chang - ,
Uygar E. Avci - ,
Andrew C. Kummel - , and
Kyeongjae Cho *
The polarization switching mechanism in ferroelectric ZrO2 involves the nucleation and subsequent migration of nonpolar domain boundaries; however, the fundamental mechanism driving this process remains inadequately understood. The present study introduces a mechanism for nearly barrierless polarization switching in 180° domain walls, facilitated by a the half-unit-cell nonpolar phase between oppositely polarized domains. Based on density functional theory (DFT) calculations, two types of 180° domain walls are explored, featuring head-to-head and tail-to-tail polarization boundaries, with nonpolar orthorhombic Pbcm and tetragonal P42/nmc phases as the respective domain walls. The calculations reveal exceptionally low energy barriers of 17.5 and 10.1 meV for migrating these Pbcm and P42/nmc boundaries by half a unit cell through the domains. An evaluation of the impact of defects on domain wall motion is achieved by introducing 2% oxygen vacancies or 3% Si doping, which induces a significant increase in the barrier motion activation energy, suggesting that defects serve as barriers to polarization switching.
Investigating T Cell Immune Dynamics and IL-6’s Duality in a Microfluidic Lung Tumor Model
Parvaneh Sardarabadi - ,
Kang-Yun Lee - ,
Wei-Lun Sun - ,
Amir Asri Kojabad - , and
Cheng-Hsien Liu *
This publication is Open Access under the license indicated. Learn More
Interleukin 6 (IL-6), produced by immune cells, is crucial in promoting T cell trafficking to infection and inflammation sites, influencing various physiological and pathological processes. Concentrations of IL-6 and other cytokines and chemokines can influence T cell differentiation and activation. Understanding the dual faces of IL-6 within the tumor microenvironment is crucial to understanding its role. A flow-based microsystem was designed to investigate CD4+ T cell activation in response to different IL-6 gradients in an under-control 3D culture. The study found that cancer cells’ response to varying IL-6 concentrations was dynamic and dose-sensitive, with immune cell migration rates showing sensitivity to the IL-6 gradient. A549 cell expansion increases gradually and time-dependently with 50 ng of IL-6, while Jurkat cell migration follows a time-dependent pattern. However, when a total of 100 ng IL-6 concentration is applied, A549 cells expand rapidly, potentially influencing Jurkat cell migration. Jurkat cell mobility is lower, possibly due to increased A549 cell presence and heightened cell–cell interactions. Different IL-6 concentration gradients can modulate the expression of some CD markers like CD69 and programed cell death protein 1 in CD4+ T cells, suggesting that IL-6 concentration gradients affect immune cell phenotypes. This suggests that IL-6 plays a crucial role in activating T helper cells and may be involved in the later phases of inflammation. Also, the increased levels of IFN-γ and TNF-α highlight IL-6’s impact on T cell inflammatory response. This study emphasizes the intricate effects of IL-6 on T cell activation, phenotype, cytokine production, and phenotypic heterogeneity, providing valuable insights into immune response modulation in an experimental setting.
Perovskite/Silicon Tandem Solar Cells Above 30% Conversion Efficiency on Submicron-Sized Textured Czochralski-Silicon Bottom Cells with Improved Hole-Transport Layers
Angelika Harter *- ,
Kerem Artuk - ,
Florian Mathies - ,
Orestis Karalis - ,
Hannes Hempel - ,
Amran Al-Ashouri - ,
Steve Albrecht - ,
Rutger Schlatmann - ,
Christophe Ballif - ,
Bernd Stannowski - , and
Christian M. Wolff *
This publication is Open Access under the license indicated. Learn More
In perovskite/silicon tandem solar cells, the utilization of silicon heterojunction (SHJ) solar cells as bottom cells is one of the most promising concepts. Here, we present optimization strategies for the top cell processing and their integration into SHJ bottom cells based on industrial Czochralski (Cz)-Si wafers of 140 μm thickness. We show that combining the self-assembled monolayer [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid (Me-4PACz) with an additional phosphonic acid (PA) with different functional groups, can improve film formation when used as a hole transport layer improving wettability, minimizing shunt fraction and reducing nonradiative losses at the buried interface. Transient surface photovoltage and transient photoluminescence measurements confirm that the combined Me-4PACz/PA layer has similar charge transport properties to Me-4PACz alone. Moreover, this work demonstrates the potential for thin, double-side submicron-sized textured industry-relevant silicon bottom cells yielding a high accumulated short-circuit current density of 40.2 mA/cm2 and reaching a stabilized power conversion efficiency of >30%. This work paves the way toward industry-compatible, highly efficient tandem cells based on a production-compatible SHJ bottom cell.
Hierarchical Nano/Micro-Array Structured CuMgAl-LDH/rGO Hybrids for Remarkably Improved Flame Retardancy and Smoke Suppression Performance of Flexible Polyvinyl Chloride
Zixuan Zhang - ,
Yuyang Chen - ,
Defu Wang - ,
Yanjun Lin *- ,
Kaitao Li - ,
Guoli Fan *- , and
Feng Li
In this study, we explored the rational integration of layered double hydroxides (LDHs) with reduced graphene oxide (rGO) to create a hierarchical nano/microarray structured CuMgAl-LDH/rGO hybrid aimed at enhancing the flame retardancy and smoke suppression properties of polymer nanocomposites. The results indicated that the limiting oxygen index (LOI) value of the G-CuMgAl/polyvinyl chloride (PVC) composite reached 35.8%, reflecting a 6.4% increase compared to pristine PVC (29.4%), and achieved a UL-94 V-0 rating. Furthermore, in comparison to pristine PVC, the peak heat release rate (PHRR) of the G-CuMgAl/PVC composite was significantly reduced by 40.2%; the total heat release rate (THR) decreased by 24.3%; the maximum average heat release rate (MARHE) diminished by 41.6%; the peak smoke production (PSPR) decreased by 37.8%; the total smoke production (TSP) was reduced by 31.3%; and the average effective heat of combustion (av-EHC) decreased by 15.2%. The enhanced flame retardancy and reduced smoke production can primarily be attributed to the multiple synergistic interactions among the highly dispersed constituents and the nano/microstructures, which effectively impede the transfer of heat, mass, and O2 from various directions while preventing further combustion of the underlying matrix by creating a tortuous path in the condensed phase. Additionally, this study provides a novel perspective on the design and synthesis of structured LDHs/rGO hybrids, with the potential to enhance flame retardancy and smoke suppression properties across a broad spectrum of polymer materials.
Iron Phosphide Nanobundles for Efficient Electrochemical Hydrogen Evolution Reaction in Acidic and Basic Media
Shubham Sharma - ,
Nishan Khatri - ,
Sharad Puri - ,
Menuka Adhikari - ,
Phadindra Wagle - ,
David N. McIlroy - ,
A. Kaan Kalkan *- , and
Yolanda Vasquez *
This publication is Open Access under the license indicated. Learn More
Earth-abundant transition metal phosphide (TMP) nanomaterials have gained significant attention as potential replacements for Pt-based electrocatalysts in green energy applications, such as the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and overall water splitting. In particular, FeP nanostructures exhibit superior electrical conductivity and high stability. Moreover, their diverse composition and unique crystal structures position FeP nanomaterials as emerging candidates for HER electrocatalysts. However, the synthesis or fabrication method employed for FeP nanostructures can significantly affect their overall electrocatalytic properties. For example, the solution synthesis of pure-phase FeP nanostructures remains challenging due to the formation of multiple binary phases and undesirable agglomeration. In this work, we use a simple approach to synthesizing FeP nanobundles by reacting β-FeOOH (iron oxyhydroxide) with trioctylphosphine (TOP). FeP nanobundles were evaluated as HER electrocatalysts in both acidic and basic conditions, demonstrating good HER activity with overpotential values of 170 and 338 mV at a current density of −10 mA cm–2 in acidic and alkaline solutions, respectively. Additionally, they exhibited low values of Tafel slopes in both acidic and alkaline environments. In acidic media with a pH of 0.45, the nanobundles showed no signs of deterioration for up to 15 h (−50 mA cm−2). In basic media with a pH of 13.69, the nanobundles remain stable for up to 8 h (−50 mA cm−2). These results demonstrate a simple and effective method for producing highly efficient earth-abundant and cost-effective TMP-based electrocatalysts, which could play a vital role in the hydrogen economy of the future.
Molybdenum Carbide Catalyst Enables Efficient Conversion of Chlorinated Volatile Organic Waste into Syngas through Catalytic Steam Reforming
Feng Lin - ,
Zezhi Chen *- ,
Huijuan Gong *- ,
Xiaoshu Wang - , and
Yong Qin
Catalytic steam reforming offers a groundbreaking approach for converting industrial chlorinated volatile organic compound (CVOC) waste into valuable syngas (H2 and CO) and recovering HCl. However, the lack of C–Cl bond activation ability in traditional transition metal catalysts results in their insufficient reforming activity toward CVOCs. Herein, a novel molybdenum carbide (β-Mo2C) catalyst is developed and loaded onto a γ-Al2O3 support synthesized through a self-assembly method. The γ-Al2O3 support provides abundant unsaturated coordinated Al3+ ions, which effectively anchor and disperse β-Mo2C nanoparticles. In the catalytic steam reforming reaction at 600 °C, the β-Mo2C/γ-Al2O3 catalyst achieves a conversion efficiency higher than 95% and syngas yields of 82.4–92.3% for various typical industrial CVOCs. The mechanistic research reveals that the coordination between C and Mo atoms in β-Mo2C leads to a slightly electron-deficient state of the Mo sites, accompanied by a high density of unoccupied 4d orbitals. These characteristics are highly advantageous for the adsorption and dechlorination of CVOC molecules. The produced nonchlorinated intermediates can subsequently be oxidized to CO and H2 by hydroxyl radicals on adjacent Mo sites.
Biocompatible PVAc-g-PLLA Acrylate Polymers for DLP 3D Printing with Tunable Mechanical Properties
Shibam Pal - ,
Utreshwar Arjun Gavhane - , and
Asha S. K *
The technological advancement of Additive Manufacturing has enabled the fabrication of various customized artifacts and devices, which has prompted a huge demand for multimaterials that can cater to stringent mechanical, chemical, and other functional property requirements. Photocurable formulations that are widely used for Digital Light Processing (DLP)/Stereolithography (SLA) 3D printing applications are now expected to meet these new challenges of hard and soft or stretchable structural requirements in addition to good resolution in multiple scales. Here we present a biocompatible photocurable resin formulation with tunable mechanical properties that can produce hard or stretchable elastomeric 3D printed materials in a graded manner. Acrylate poly(lactic acid) (PLA) grafted polyvinyl acetate (PVAc) polymer was mixed with hydroxyl ethyl methacrylate (HEMA) and hydroxyl ethyl acrylate (HEA) as reactive diluents (50–70 wt %) in various compositions to form a series of photocurable resin formulations. Depending on the nature of the reactive diluent (HEMA or HEA) and their weight percentage, the mechanical properties of the 3D printed parts could be fine-tuned from hard (Tensile strength 20.6 ± 2 MPa, elongation 2 ± 1%) to soft (Tensile strength 1.1 ± 0.2 MPa, elongation 62 ± 8%) materials. The printed materials displayed remarkable dye absorption (95%), showing stimuli-responsive behavior for dye release (with respect to both pH and enzyme), while also demonstrating high cell viability (>90%) for mouse embryonic (WT-MEF) cells and degradability in PBS solution. These biobased 3D printing resins have the potential for a variety of applications, including tissue engineering, soft robotics, dye absorption, and elastomeric actuators.
Supramolecular Modification of Graphene Sponge with a Porphyrin Derivative Enhances the Photothermal Conversion Efficiency of a Solar Steam Generator
Elif Erçarıkcı - ,
Demet Demirci Gültekin - ,
Ezgi Topçu - ,
Züleyha Kudaş - ,
Murat Alanyalıoğlu - , and
Kader Dağcı Kıranşan *
This publication is Open Access under the license indicated. Learn More
Solar energy seems to be a promising solution for obtaining clean water from saltwater and wastewater. With the solar steam generator system, it is possible to effectively acquire clean water from wastewater with a low-cost, sustainable, and environmentally friendly approach. In this study, PRF/GGSM, prepared by modification of gradient graphene sponge material (GGSM) with porphyrin derivative supramolecules (PRF), was investigated as a photothermal material for solar steam generation. PRF/GGSM possessing graphene and PRF served as ideal solar thermal converters that could easily gather sunlight. This material owing to its microporous and gradient hydrophilic structure has achieved a solar thermal conversion efficiency of up to 92% under 1 sun, corresponding to the water evaporation rate of 3.8 kg h–1 m–2. Moreover, this study exhibited that PRF/GGSM can efficiently generate clean water from seawater, wastewater, and even concentrated acid and alkali solutions.
Multi-Electrode Extended Gate Field Effect Transistors Based on Laser-Induced Graphene for the Detection of Vitamin C and SARS-CoV-2
Heshmat Asgharian - ,
Vinay Kammarchedu - ,
Pouya Soltan Khamsi - ,
Caroline Brustoloni - , and
Aida Ebrahimi *
Despite the clinical data showing the importance of ascorbic acid (AA or vitamin C) in managing viral respiratory infections, biosensors for their simultaneous detection are lacking. To address this need, we developed a portable and wireless device for simultaneous detection of AA and SARS-CoV-2 virus by integrating commercial transistors with printed laser-induced graphene (LIG) as the extended gate. We studied the effect of laser printing pass number and showed that with two laser printing passes (2-pass LIG), the sensor sensitivity and limit of detection (LOD) for AA improved by a factor of 1.6 and 12.8, respectively. Using complementary characterization methods, we attribute the improved response to a balanced interplay of crystallinity, defect density, surface area, surface roughness, pore density and diameter, and mechanical integrity/stability. These factors enhance analyte transport, reduce noise/variability, and ensure consistent sensor performance, making 2-pass LIG the most effective material in this work. Our sensors exhibit promising performance for detecting AA with a selective response in the presence of common salivary interfering molecules, with sensitivity and LOD of 73.67 mV/dec and 54.04 nM in 1× phosphate buffered saline and 81.05 mV/dec and 78.34 nM in artificial saliva, respectively. We also showed that functionalization of the 2-pass LIG gate with S-protein antibody enables the detection of SARS-CoV-2 protein antigens with an ultralow LOD of 52 zg/mL─an improvement of more than 10-fold compared to 1-pass LIG─and 4 particles/mL for virion mimics with a selective response against influenza virus and multiple human coronavirus strains. With low signal drift/hysteresis and wireless capabilities, the developed device holds great potential for improving at-home monitoring and clinical decision-making.
Enhancing Organic Pollutant Degradation Efficiency through a Photocatalysis–Electro-Fenton System via MoS2 Crystal Morphology Regulation
Huan Zhang - ,
Chang Liu - ,
Wenrong Dong - ,
Peng Chen *- ,
Feifei Jia *- , and
Shaoxian Song
A photocatalysis–electro-Fenton (PEF) system was constructed via molybdenum disulfide (MoS2) to remove tetracycline (TC) without an external oxidant supply and solution pH adjustment. In the system, original graphite felt (GF) was used as a cathode, from which H2O2 was in situ generated continuously under power. MoS2 was motivated by visible light to facilitate the cycle of Fe2+/Fe3+, enhancing the Fenton process to produce •OH. The experimental results showed that the system can increase the degradation rate of pollutants by more than 5 times. Moreover, the quenching and electron paramagnetic resonance (EPR) tests demonstrated that •OH was the dominant active species. X-ray photoelectron spectroscopy (XPS) characterization, Mo concentration, and cycle experiments proved the excellent catalytic activity and chemical stability of MoS2. It is worth mentioning that the photocatalytic performances of different morphologies of MoS2 (flower, flake, and radar) were compared. As a result, flower-like MoS2 exhibited a much superior photoresponse than flake and radar, which could accelerate the Fe2+/Fe3+ cycle further effectively. These findings highlight the morphology–performance relationship of MoS2 under a PEF system and the mechanisms of contaminant degradation, which is of great significance for developing photoelectric Fenton technology.
Investigating the Potential of Cr3+-Doped Pyroxene for Highly Sensitive Optical Pressure Sensing
Maja Szymczak - ,
Ke Su - ,
Lefu Mei *- ,
Marcin Runowski - ,
Przemyslaw Woźny - ,
Qingfeng Guo - ,
Libing Liao - , and
Lukasz Marciniak *
Luminescent manometry has gained significant popularity in recent years due to its capability to provide in situ pressure measurements in a remote manner. Therefore, there is a growing need to identify phosphors with pressure-dependent spectroscopic properties that can be utilized to develop highly sensitive pressure sensors operating over a wide pressure range. Hence, we present a novel temperature-invariant luminescent manometer based on Cr3+ ion emission in pyroxene Ca0.8Sr0.2MgSi2O6:Cr3+. We utilized two readout modes, including an innovative luminescent pressure sensing ratiometric approach based on the broad emission band associated with the 4T2g → 4A2g electronic transition of Cr3+ ions. This approach provided an exceptionally high sensitivity of SR = 50.7 ± 0.5% GPa–1 and ensured temperature-independent pressure measurements, thus offering highly reliable readouts. Furthermore, the proposed readout mode, which leverages changes in luminescence kinetics, demonstrated high sensitivity at high pressure at around 5 GPa (SR ∼ 8 ± 0.2% GPa–1) surpassing the performance of luminescence kinetics-based manometers reported to date. Consequently, Ca0.8Sr0.2MgSi2O6:Cr3+ emerges as a highly promising phosphor with significant application potential for pressure sensing across a broad pressure range.
Residual Ferromagnetic Regions Affecting the First-Order Phase Transition in Off-Stoichiometric Fe–Rh
Alex Aubert *- ,
Konstantin Skokov - ,
Andrei Rogalev - ,
Alisa Chirkova - ,
Benedikt Beckmann - ,
Fernando Maccari - ,
Elvina Dilmieva - ,
Fabrice Wilhelm - ,
Vivian Nassif - ,
Léopold V. B. Diop - ,
Enrico Bruder - ,
Julia Löfstrand - ,
Daniel Primetzhofer - ,
Martin Sahlberg - ,
Esmaeil Adabifiroozjaei - ,
Leopoldo Molina-Luna - ,
Gabriel Gomez - ,
Benedikt Eggert - ,
Katharina Ollefs - ,
Heiko Wende - , and
Oliver Gutfleisch
Among the magnetocaloric materials featuring first-order phase transitions (FOPT), FeRh is considered as a reference system to study the FOPT because it is a “simple” binary system with a CsCl structure exhibiting a large adiabatic temperature change. Recently, ab initio theory predicted that changes in the Fe/Rh stoichiometry in the vicinity of equiatomic composition strongly influence the FOPT characteristics. However, this theoretical prediction was not clearly verified experimentally. Here, we investigated the composition dependence of the transitional hysteresis in FeRh. It is shown that a Fe excess of only 1 at. % induces a ferromagnetic state in the whole temperature range (from 5 K up to Tc) for a minor portion of the sample (≈10%), while 5 at. % is enough to completely eliminate the FOPT. Element-specific X-ray magnetic circular dichroism (XMCD) measurements suggest that this ferromagnetic contribution arises from residual FeRh ferromagnetic regions. We attribute the formation of such domains to Fe antisite defects, as Mössbauer spectroscopy demonstrates the presence of Fe atoms located at the 1b (Rh) sites in the CsCl-type structure. As a consequence, compared with the equiatomic composition, the slightly Fe-rich sample exhibits completely different FOPT properties, influencing the magnetocaloric performances. Thus, our study sheds light on the origin of the remarkable stoichiometric sensitivity of the FOPT behavior in FeRh. These insights have broader implications for understanding FOPT dynamics and the role of residual ferromagnetic domains.
Templates-Built Structural Designs for Piezoelectrochemical Pressure Sensors
Hongjian Zhang - ,
Yi Fang - ,
Junki Lee - ,
Chang Kyu Jeong *- , and
Yong Zhang *
Self-powered sensors, capable of detecting static and dynamic pressure without an external power source, are pivotal for advancements in human–computer interaction, health monitoring, and artificial intelligence. Current sensing technologies, however, often fall short of meeting the growing needs for precise and timely pressure monitoring. This article introduces a novel self-powered pressure sensor utilizing electrochemical reactions. The sensor’s ion conduction path and internal resistance adjust in response to external stress across a broad range. Its three-dimensional structure, crafted by using a simple template on the electrolyte, enables the efficient and cost-effective detection of various mechanical stimuli. This device not only achieves an optimized power density of approximately 2.34 mW cm–2─surpassing most existing technologies─but also features excellent flexibility, quick response, and recovery times (0.15 and 0.19 s respectively); high durability (2000 cycles); and a broad sensing range (0.23–20 kPa). Moreover, it serves as an ionic touchpad, enhancing data collection and recognition, and integrates seamlessly with a mouthpiece for accurate, real-time monitoring of respiratory activities. This innovative sensor offers minimal cost and simple process requirements while providing multifunctional capabilities for energy harvesting and pressure sensing, marking a significant step forward in the design of next-generation sensors.
Exploring Bonding Configurations in MnBi2Te4-Type Materials
Romakanta Bhattarai - and
Trevor David Rhone *
We perform a systematic investigation of several crystal structures, based on monolayer MnBi2Te4, of the form MnBiBiiXi2Xii2 using first-principles calculations. Our analysis shows that the most energetically favorable bonding configuration of the constituent elements in monolayer MnBiBiiXi2Xii2 is determined by the bond length between the Mn atom and its nearest X-site atoms. Tuning the bonding configuration of the material alters the magnetic, electronic, and topological properties. We also calculate the magnetic exchange parameters and magnetic anisotropy energy of the predicted structures. The calculations show that the elements at the X sites mainly determine the magnetic properties. Finally, we propose a stable phase of monolayer MnBi2S2Te2 (i.e., γ-MnBi2S2Te2) that exhibits the quantum anomalous Hall effect (QAHE). This study demonstrates that the bonding configuration of MnBi2Te4-type materials provides avenues for tuning the magnetic, electronic, and topological properties of van der Waals (vdW) materials.
Hydrogel-Based Network Metamaterials with Biological Tissue-like Poisson’s Ratio Behavior and Stress Response
Yisong Qiu - ,
Hongfei Ye - ,
Shuaiqi Zhang - ,
Hongwu Zhang - , and
Yonggang Zheng *
Soft network metamaterials are widely used in fields such as flexible electronics, tissue engineering, and biomedicine due to their superior properties including low density, high stretchability, and high breathability. However, the prediction and customization of the nonlinear mechanical behavior of soft network metamaterials remain a challenging problem. In this study, a family of hydrogel-based network metamaterials with biological tissue-like mechanical properties are developed based on a machine learning-driven optimization design method. Numerical and experimental results explain the relationship between the mechanical properties of the designed metamaterials and their microstructural features and stretching ratios. The results indicate that the hydrogel-based network metamaterials exhibit J-shaped stress-deformation (σ–λ) behavior similar to biological tissues. This phenomenon arises from the transition of the deformation mode of metamaterials from bending-dominated to stretching-dominated as the stretching ratio increases. Based on the proposed design scheme, the Poisson’s ratio of metamaterials can be adjusted within a remarkably wide range of −1.06 to 1.34. Furthermore, through optimizing the design parameters of the metamaterial, the customization of network metamaterials with biological tissue-like zero Poisson’s ratio behavior and stress response is achieved. The potential applications of hydrogel-based network metamaterials are demonstrated through artificial skin and LED integrated device. This research offers novel insights into predicting, designing, and fabricating the mechanical behavior of soft network metamaterials.
Balancing Interfacial Toughness and Intrinsic Dissipation for High Adhesion and Thermal Conductivity of Polymer-Based Thermal Interface Materials
Jiashuo Sheng - ,
Zhian Zhang - ,
Yunsong Pang - ,
Xiaxia Cheng - ,
Chen Zeng - ,
Jian-Bin Xu - ,
Leicong Zhang - ,
Xiaoliang Zeng - ,
Linlin Ren *- , and
Rong Sun
In recent years, adhesive thermal interface materials have attracted much attention because of their reliable adhesion properties on most substrates, preventing moisture, vibration impact, or chemical corrosion damage to components and equipment, as well as solving the heat dissipation problem. However, thermal interface materials have a huge contradiction between strong adhesion and high thermal conductivity. Here, we report a polymer-based thermal interface material consisting of polydimethylsiloxane/spherical aluminum fillers, which possesses both adhesion properties (adhesion strength of 3.59 MPa and adhesion toughness of 1673 J m–2 and enhanced thermal conductivity of 3.90 W m–1 K–1). These excellent properties are attributed to the modified chain structure by introducing acrylate accelerators into the polydimethylsiloxane network, thereby striking a balance between interfacial toughness and intrinsic dissipation. The addition of thermally conductive aluminum fillers not only increases the thermal conductivity but also improves the bulk energy dissipation of the thermal interface material. This work provides a novel strategy for designing a novel thermal interface material, leading to new ideas in long-term applications in high-power electronics.
Nonhalogenated Solvent-Processed Efficient Ternary All-Polymer Solar Cells Enabled by the Introduction of a Naphthyloxy Group into the Side Chain of Polymer Donors
Priyanka Yadav - ,
Hyerin Kim - ,
Thavamani Gokulnath - ,
Jin Soo Yoo - ,
Myeong Jin Jeon - ,
Raja Kumaresan - ,
Ho-Yeol Park *- , and
Sung-Ho Jin *
Conjugated polymer donors are crucial for enhancing the power conversion efficiencies (PCEs) in all-polymer solar cells (All-PSCs) in nonhalogenated solvents. In this work, three wide-band-gap polymer donors (Sil-D1, Ph-Sil-D1, and Nap-Sil-D1) based on dithienobenzothiadiazole (DTBT) and benzodithiophene (BDT) donor moieties optimized by side chain engineering were designed and synthesized. Alkyl (Sil-D1), phenyloxy (Ph-Sil-D1), and naphthyloxy (Nap-Sil-D1) alkyl siloxane side chain units were incorporated into these polymer donors, respectively. Notably, the Nap-Sil-D1 polymer donor had a greater conjugation length, π-electron delocalization, and improved dipole moment. The deepest highest occupied molecular orbital level of Nap-Sil-D1, with a high absorption coefficient, showed better aggregation properties. In addition, reduced bimolecular recombination and trap-state density generated a high charge transfer to cause a significant enhancement of open-circuit voltage, current density, and fill factor values of 0.94 V, 25.5 mA/cm2, and 70.4%, respectively, for the Nap-Sil-D1-blended All-PSC ternary device (PM6:Nap-Sil-D1:PY-IT), with the highest PCE of 16.8% in the o-xylene solvent, compared to other polymers (Sil-D1 and Ph-Sil-D1) with PCEs of 15.5 and 16.2%. As a result, this optimized device architecture was found to be the most promising as a nonhalogenated solvent processed in additive-free ternary All-PSCs with good stability.
Improvement of Thermal Stability of Charges in Polylactic Acid Electret Films for Biodegradable Electromechanical Sensors
Yi Qin - ,
Xingchen Ma *- ,
Zehai Ruan - ,
Xinhao Xiang - ,
Zhiming Shi - ,
Lian Zhou - ,
Qianqian Hu - , and
Xiaoqing Zhang *
Eco-friendly sensors fabricated from biocompatible and biodegradable materials are promising candidates for wearable and implantable electronics due to their environmental sustainability and biosafety. This article reports a fully biodegradable electromechanical sensor (FBES) utilizing a sandwich structure with macro ripple structured polylactic acid (PLA) electret films acting as sensitive layers and molybdenum (Mo) sheets serving as electrodes for a wearable device application. The stability of the space charge stored within the PLA film has been enhanced by introducing an internal cellular structure and improving the polarization process. A macro ripple structure of the PLA layer with higher deformation is a great guarantee for boosting the pressure sensitivity. The results indicate that inserting cell microstructures and optimizing the polarization process significantly improve the charge storage stability of PLA films by nearly 55%. This enhancement is attributed to several factors, including the extended charge drift path of the charges in cellular films, a synergy effect of surface charges, and “macroscopic” dipole charges distributed in the cells. The fabricated sensor achieves a high sensitivity of 1000 pC/kPa, a wide pressure detection range of 0.03–62.4 kPa, and satisfactory stability. Such sensors are not only sensitive to body movements but also to subtle physiological signals, satisfying the diverse needs of wearable healthcare. Importantly, all the composition materials of the sensor can be completely degraded after their service, aligning with the environmentally friendly principles of green development.
UiO-66(Zr)-2OH-Supported Pd0 NP Catalysts Accelerated a Fenton-Like Reaction: Iron Cycling and Hydrogen Peroxide Generation Achieved Simultaneously
Ying Gao - ,
Qinqin Chen - ,
Xinhao Shen - ,
Shuang Yao - ,
Zhiwen Jiang - ,
Sanjian Ma - ,
Hailiang Yang - ,
Juanhong Li - ,
Zixia Lin - , and
Xin Liu *
Both the sluggish kinetics of Fe(II) regeneration and usage restriction of H2O2 have severely hindered the scientific progress of the Fenton reaction toward practical applications. Herein, a reduction strategy of activated hydrogen, which was used to simultaneously generate H2O2 and accelerate the regeneration of ferrous in a Fenton-like reaction based on the reduction of activated hydrogen derived from H2, was proposed. Two types of composite catalysts, namely, Pd/UiO-66(Zr)-2OH and Pd@UiO-66(Zr)-2OH, were successfully prepared by loading nano-Pd particles onto the outer and inner pores of UiO-66(Zr)-2OH in different loading modes, respectively. They were used to enhance the reduction of activated hydrogen. The characterization results based on the analysis of scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy revealed that the materials were successfully prepared. By using a trace amount of ferrous iron and without adding H2O2, trimethoprim (C0 = 20 mg·L–1), as a target pollutant, could be nearly 100% degraded within 180 min in the reaction system composed of these two materials. The cycle of iron and the self-generation of H2O2 were verified by the detection of ferrous H2O2 in the system. Density functional theory calculation results further confirmed that the pore-filled Pd0 NPs, as the main catalytic site for Pd@UiO-66(Zr)-2OH, could produce H2O2 under the combined action of hydrogen and oxygen. The Pd@UiO-66(Zr)-2OH system had excellent stability after multiple applications (at least 6 cycles), all of which resulted in 100% removal of trimethoprim. The degradation efficiency of the Pd/UiO-66(Zr)-2OH system for TMP gradually decreased from 97 to 80% after six cycles. The results of electron paramagnetic resonance combined with classical radical burst experiments revealed the degradation pathways in the reaction system with hydroxyl radicals and singlet oxygen as the main reactive oxygen particles.
A Multimode Dynamic Color-Changing Device for Smart Windows Based on Integrating Thermochromic and Electrochromic Properties
Chang Xiao - ,
Chengcheng Wang *- ,
Liping Zhang *- , and
Shaohai Fu
Electro- and thermochromic materials have been greatly applied in smart windows and displays due to the excellent properties of color variation and solar radiation. However, the mono color and single response to voltage and temperature hinder their application and development. Here, a multimode dynamic color-changing device (T/ECD) was developed by integrating the electrochromic property of synthetic viologen dyes and the thermochromic properties of hydroxypropyl acrylate (HPA). The T/ECD achieves four modes of optical regulation, namely, colorless transparent state, tinted transparent state, colorless opaque state, and tinted opaque state, which can be regulated independently/coordinately using heat and voltage. The optimized T/ECD switched color at 1.2 V with 15 s or adjusted the transparent/opaque state at >34 °C with 46 s. In addition, based on the red viologen (ViO-R), green viologen (ViO-G), and blue viologen (ViO-B) dyes, colorful T/ECDs were successfully designed and fabricated, and T/ECDs have excellent cycling properties, expanding the application requirement. Moreover, we demonstrated their application in smart windows and privacy protection. The design philosophy and successful exploration have great prospects for energy-saving buildings, displays, and information masking/storage systems.
Innovative Multielement Modification of Pitch-Derived Two-Dimensional Carbon Nanosheets as Anodes for Superior Performance Sodium-Ion Batteries
Jian Wang - ,
Peihua Li - ,
Jingru Chen - ,
Yachen Xin - ,
Chenhang Huangfu - ,
Xiaohong Li - ,
Wanggang Zhang *- , and
Yiming Liu *
The development of advanced anode materials for sodium-ion batteries (SIBs) using pitch-based carbon materials has the advantages of low cost, high electrical conductivity and easy structural modification. In this research, various well-established modification techniques for petroleum pitch are integrated, including the use of recrystallized NaCl as molten salt template, pretreatment and high-temperature carbonization under a pure oxygen atmosphere, and the introduction of heteroatoms (N and S) by hydrothermal methods. The resulting two-dimensional carbon nanosheets with multielement modification exhibit enhanced Na+ storage properties, thereby bringing higher cycling stability and superior rate performance. Due to its specific structure and chemical composition, NS-P-OPDC exhibited a high reversible capacity of 406.77 mAh g–1 at a current density of 100 mA g–1 and a superior rate performance of 193.20 mAh g–1 at a current density of 3 A g–1 after being applied to the anode of SIB half-cell. Especially, a capacity retention of 97.7% was still achieved after 4000 cycles. Meanwhile, the full-cell assembled by Na3V2(PO4)3 (NVP) cathode and NS-P-OPDC anode could provide a reversible capacity of 235.30 mAh g–1 at a current density of 300 mA g–1. This application proves to advance petroleum pitch-based high-performance electrodes toward greater efficiency in electrochemical energy storage.
Honeycomb-like Microthermal Traps on a Photothermal Surface for Highly Efficient Solar Evaporation
Xiaofei Liu - ,
Lanlan Hou - ,
Rongjun Hu - ,
Huiying Zhang - ,
Xuefeng Zhang - ,
Xinran Ge - ,
Ying Zhang - ,
Guichu Yue - ,
Zhimin Cui - ,
Jie Bai - ,
Jingchong Liu - ,
Nü Wang *- ,
Yong Li *- , and
Yong Zhao *
Solar evaporation is an ecofriendly and practical method for seawater desalination. The photothermal layer, which absorbs solar energy and converts it to thermal energy, plays a crucial role in enhancing the efficiency of the evaporator. However, structural design methods for photothermal layers are often complex and energy-intensive. This work reports a simple and efficient strategy for fabricating a necklace-like beaded nanofiber self-organized honeycomb-structured photothermal material. The honeycomb-like cavities form numerous microscale thermal traps, achieving thermal localization while maintaining high energy utilization efficiency, which not only increases light absorption but also facilitates the diffusion and escape of steam. Besides, the hydrophobic honeycomb layer separates the photothermal layer and the interface water, which reduces considerable heat conduction loss and achieves an effective antisalting performance. These functional features endow the evaporator with an evaporation efficiency of 92.9%, and the evaporation rate reaches 2.11 kg m–2 h–1 at 1 sun irradiance, demonstrating its great potential for practical solar-driven seawater desalination under natural sunlight.
Enhancing the Thermoelectric Performance of n-Type Mg3.2Sb1.5Bi0.5 by Reducing Lattice Thermal Conductivity through the Incorporation of Chlorine-Containing Compounds
Jing-xuan Liang - ,
Lu Yu - ,
Si-tong Luo - ,
Si-tong Wei - ,
Zhi-bo Wei - ,
Tao Wang - ,
Yun-tian Jiang - ,
Wei-yu Song - , and
Shu-Qi Zheng *
Mg3Sb2-based thermoelectric materials are characterized by their economic efficiency, nontoxicity, and environmental friendliness and represent a highly promising and eco-friendly functional material for midtemperature applications. To achieve a higher thermoelectric performance, we introduced two compounds, LaCl3 and CeCl3, into Mg3.2Sb1.5Bi0.5 under the guidance of first-principles calculations. The Mg3.2Sb1.5Bi0.5 + 0.03CeCl3 sample reached a maximum ZT value of approximately 1.6 at 723 K. The calculations indicate that two n-type dopants, LaCl3 and CeCl3, can adequately improve the band structure of Mg3Sb2, and the introduction of Cl atoms will also lead to lattice distortion and reduce the lattice thermal conductivity (κL). Experimental results demonstrate that the introduction of Cl atoms efficiently reduces the thermal conductivity while improving the electrical transport properties. Specifically, the Mg3.2Sb1.5Bi0.5 + 0.03CeCl3 sample achieved an exceptionally low κL of 0.3 W m–1 K–1 at 723 K, thereby validating the effectiveness of LaCl3 and CeCl3 doping. This work provides valuable insights into achieving thermoelectric decoupling in Mg3Sb2-based thermoelectric materials.
High-Performance Rotating Structure Triboelectric-Electromagnetic Hybrid Nanogenerator for Environmental Wind Energy Harvesting
Zhi Cao - ,
Hanlin Zhou - ,
Chengcheng Han - ,
Haitao Jing - ,
Zhong Lin Wang *- , and
Zhiyi Wu *
As environmental energy harvesting gains increasing importance in self-powered systems and large-scale energy demands, wind energy, as a clean, pollution-free, and renewable source, has garnered widespread attention. However, achieving efficient wind energy collection remains challenging. This study proposes a high-performance rotating structure triboelectric-electromagnetic hybrid nanogenerator designed for environmental wind energy harvesting. By optimizing the magnetic circuit design of the electromagnetic generator, the dispersed radial magnetic field is converted into a unified axial magnetic field, enabling efficient power generation with only a single annular coil, thereby simplifying the generator design and reducing manufacturing and maintenance costs. Additionally, a triboelectric nanogenerator design with soft contact friction between polycarbonate (PC) fur and fluorinated ethylene propylene (FEP) film was implemented, optimizing the spacing between the electrode and friction layers, thus enhancing output performance and device durability. Furthermore, we simulated and experimentally tested the output waveform of the designed hybrid generator structure, with the results showing a high degree of similarity, further validating the rationality of the device design and providing guidance for structural optimization. Subsequently, we achieved efficient energy storage using an energy management circuit (EMC). With the integration of the EMC, the generator successfully powered a Bluetooth temperature and humidity sensor at a wind speed of 10 m/s, achieving wireless transmission, and demonstrating its potential application in traffic signal systems and other natural environmental systems. This research provides an important reference for further exploration of novel wind energy harvesting technologies.
Reversible Antireflection Materials Inspired by Cicada Wings for Anticounterfeit and Photovoltaic Cells
Fei Liu - ,
Yuhan Sun - ,
Ze Wang *- ,
Bo Li *- ,
Shichao Niu - ,
Junqiu Zhang - ,
Zhiwu Han - , and
Luquan Ren
Antireflection (AR) surfaces are essential for the fields of flexible displays, photovoltaic industry, medical endoscope, intelligent windows, etc. Although natural creatures with well-organized micro/nanostructures have provided some coupling design principles for the rapid development of bioinspired AR materials, the mechanical vulnerability, poor flexibility, and nonadjustability have been pointed out as the drawback of these nanostructures. Here, a bioinspired reversible AR film with 4% reflectivity, 90% transmittance, and 9% haze in broadband (400–900 nm) was prepared. The flexible switching of AR performance enhancement and weakening throughout the visible wavelength band has been achieved by controlling the reversible change in the morphology of the interface structure. A variety of patterned film samples can be obtained by simply changing the template, which can be used in intelligent identification fields such as anticounterfeiting. The cycle test and photoelectric test show that the bionic reversible antireflection structure has certain stability and can effectively reduce the loss of photovoltaic cell conversion efficiency caused by mechanical deformation. It has broad application prospects in the fields of anticounterfeiting, intelligent window, flexible display, photoelectric element, and so on.
Tailored Design of a Nanoporous Structure Suitable for Thick Si Electrodes on a Stiff Oxide-Based Solid Electrolyte
Kohei Marumoto - ,
Kiyotaka Nakano - ,
Yuki Kondo - ,
Minoru Inaba - , and
Takayuki Doi *
Oxide-based all-solid-state batteries are ideal next-generation batteries that combine high energy density and high safety, but their realization requires the development of interface bonding technology between the stiff solid electrolyte and electrode. Even if the interface could be bonded, it is difficult to hold the interface, because only the electrode expands/contracts unilaterally during charge/discharge reactions. In particular, silicon (Si), which has eagerly awaited as a next-generation negative-electrode material for many years, changes in volume by several hundred percent. To solve these problems, in this work, highly porous silicon oxide (SiOx) electrodes with different porous structures were fabricated on a stiff garnet-type Li7La3Zr2O12 solid electrolyte, the three-dimensional nanoporous structure was analyzed quantitatively, and the charge/discharge characteristics were investigated. The microscopic observation and electrochemical analysis revealed how we should control the porous structure, such as sizes of pores and SiOx, size distribution, and porosity, for repeated and stable charge/discharge cycles. In addition, the resultant porous SiOx electrodes demonstrated superior charge/discharge cycle performance even when it thickened to 5 μm, whereas non-porous SiOx easily peeled off from the solid electrolyte when its thickness exceeded 0.1 μm. The thick SiOx films greatly improved the energy density per unit area (mAh cm–2). Nanosized fine pores with an interconnected open-pore architecture effectively mitigated the internal and interfacial stress upon expansion (charge)/contraction (discharge) of Si, and as a result, the thick and porous SiOx electrode maintained the interfacial joint with the stiff solid electrolyte after repeated charge/discharge cycles. These results will provide useful insights for effectively designing more practical porous SiOx powder effectively.
Role of Charge Density and Surface Area of Tailored Ionic Porous Organic Polymers for Adsorption and Antibacterial Actions
Sayantan Sarkar - ,
Argha Chakraborty - ,
Probal Nag - ,
Siddharth Singh - ,
Ritika Munjal - ,
Sivaranjana Reddy Vennapusa - ,
Hem Chandra Jha - , and
Suman Mukhopadhyay *
The development of high-performance adsorbents for environmental remediation is a current need, and ionic porous organic polymers (iPOPs), due to their high physicochemical stability, high surface area, added electrostatic interaction, and easy reusability, have already established themselves as a better adsorbent. However, research on the structural design of high-performance iPOP-based adsorbents is still nascent. This study explored the building blocks’ role in optimizing the polymers’ charge density and surface area to develop better polymeric adsorbents. Among the three synthesized polymers, iPOP-ZN1, owing to its high surface area and high charge density in its active sites, proved to be the best adsorbent for adsorbing inorganic and organic pollutants in an aqueous medium. The polymers were efficient enough to capture and store iodine vapor in the solid state. Further, this study tried to address using iodine-loaded polymers in antibacterial action. Iodine-loaded iPOPs show impressive antibacterial behavior against E. coli, B. subtilis, and H. pylori.
Replacing the Gallium Oxide Shell with Conductive Ag: Toward a Printable and Recyclable Composite for Highly Stretchable Electronics, Electromagnetic Shielding, and Thermal Interfaces
Abdollah Hajalilou - ,
Elahe Parvini - ,
Tiago A. Morgado - ,
Pedro Alhais Lopes - ,
M. Estrela Melo Jorge - ,
Marta Freitas - , and
Mahmoud Tavakoli *
Liquid metal (LM)-based composites hold promise for soft electronics due to their high conductivity and fluidic nature. However, the presence of α-Ga2O3 and GaOOH layers around LM droplets impairs conductivity and performance. We tackle this issue by replacing the oxide layer with conductive silver (Ag) using an ultrasonic-assisted galvanic replacement reaction. The Ag-coated nanoparticles form aggregated, porous microparticles that are mixed with styrene–isoprene–styrene (SIS) polymers, resulting in a digitally printable composite with superior electrical conductivity and electromechanical properties compared to conventional fillers. Adding more LM enhances these properties further. The composite achieves EMI shielding effectiveness (SE) exceeding 75 dB in the X-band frequency range, even at 200% strain, meeting stringent military and medical standards. It is applicable in wireless communications and Bluetooth signal blocking and as a thermal interface material (TIM). Additionally, we highlight its recyclability using a biodegradable solvent, underscoring its eco-friendly potential. This composite represents a significant advancement in stretchable electronics and EMI shielding, with implications for wearable and bioelectronic applications.
Correction to “Photo-Cross-Linkable Methacrylated Gelatin and Hydroxyapatite Hybrid Hydrogel for Modularly Engineering Biomimetic Osteon”
Yicong Zuo - ,
Xiaolu Liu - ,
Dan Wei - ,
Jing Sun - ,
Wenqian Xiao - ,
Huan Zhao - ,
Likun Guo - ,
Qingrong Wei - ,
Hongsong Fan *- , and
Xingdong Zhang
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October 28, 2024
Artificial Tactile Sensory Finger for Contact Pattern Identification Based on High Spatiotemporal Piezoresistive Sensor Array
Qiangqiang Ouyang - ,
Xiaoying Wang - ,
Shaoyi Wang - ,
Zizhen Huang - ,
Zhaohui Shi - ,
Mao Pang - ,
Bin Liu - ,
Chee Keong Tan - ,
Qintai Yang *- , and
Limin Rong *
Human fingertip tactile perception relies on the activation of densely distributed tactile receptors to identify contact patterns in the brain. Despite significant efforts to integrate tactile sensors with machine learning algorithms for recognizing physical patterns on object surfaces, developing a tactile sensing system that emulates human fingertip capabilities for identifying contact patterns with a high spatiotemporal resolution remains a formidable challenge. In this study, we present the development of an artificial tactile finger for accurate contact pattern identification, achieved through the integration of a high spatiotemporal piezoresistive sensor array (PRSA) and a convolutional neural network (CNN) model. Spatiotemporal characterization tests reveal that the artificial finger exhibits a fast temporal resolution of approximately 7 ms and achieves a two-point threshold of 1.5 mm, surpassing that of the human fingertip. To compare the performance of the artificial finger with the human finger in recognizing different patterns, we acquired pressure images by pressing the artificial finger, coated with a flexible PRSA film, onto both simple embossed and complex curved patterns while also recording human recognition results of perceiving these patterns. Experimental findings demonstrate that the artificial finger achieves higher classification accuracy in recognizing both simple and complex patterns (99.0 and 96.1%, respectively) compared to the human fingertip (69.1 and 22.7%). This artificial finger serves as a promising platform with great potential for various robotic tactile sensing applications including prosthetics, skin electronics, and robotic surgery.
The Synergic Effect of h-MoO3, α-MoO3, and β-MoO3 Phase Mixture as a Solid Catalyst to Obtain Methyl Oleate
Gabrielle Sophie Medeiros Leão - ,
Marcos Daniel Silva Ribeiro - ,
Rubens Lucas de Freitas Filho - ,
Libertalamar Bilhalva Saraiva - ,
Ramón R. Peña-Garcia - ,
Ana Paula de Carvalho Teixeira - ,
Rochel Montero Lago - ,
Flávio Augusto Freitas - ,
Silma de Sá Barros - ,
Sérgio Duvoisin Junior - ,
Yurimiler Leyet Ruiz - , and
Francisco Xavier Nobre *
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Extensive research in the last few decades has conclusively demonstrated the significant influence of experimental conditions, surfactants, and synthesis methods on semiconductors’ properties in technological applications. Therefore, in this study, the synthesis of molybdenum oxide (MoO3) was reported by the addition of 2.5 (MoO3_2.5), 5 (MoO3_5), 7.5 (MoO3_7.5), and 10 mL (MoO3_10) of nitric acid, obtaining the respective concentrations of 0.6, 1.10, 1.6, and 0.6 mol L–1. In this study, all samples were synthesized by the hydrothermal method at 160 °C for 6 h. The materials obtained were structurally characterized by X-ray diffraction (XRD) and structural Rietveld refinement, Raman spectroscopy, and infrared spectroscopy (FTIR), confirming the presence of all crystallographic planes and bands associated with active modes for the pure hexagonal phase (h-MoO3) when the solution’s concentration was 0.6 mol L–1 of nitric acid. For concentrations of 1.10, 1.60, and 2.10 mol L–1, the presence of crystallographic planes and active modes associated with the formation of mixtures of molybdenum oxide polymorphs was confirmed, in this case, the orthorhombic, monoclinic, and hexagonal phases. X-ray photoelectron spectroscopy reveals the occurrence of the states Mo4+, Mo5+, and Mo6+, which confirm the predominance of the acid Lewis sites, corroborating the analysis by adsorption of pyridine followed by characterization by infrared spectroscopy. The images collected by scanning electron microscopy confirmed the information presented in the structural characterization, where microcrystals with hexagonal morphology were obtained for the MoO3_2.5 sample. In contrast, the MoO3_5, MoO3_7.5, and MoO3_10 samples exhibited hexagonal and rod-shaped microcrystals, where the latter morphology is characteristic of the orthorhombic phase. The catalytic tests carried out in the conversion of oleic acid into methyl oleate, using the synthesized samples as a heterogeneous catalyst, resulted in conversion percentages of 52.5, 58.6, 69.1, and 97.2% applying the samples MoO3_2.5, MoO3_5, MoO3_7.5, and MoO3_10, respectively. The optimization of the catalytic tests with the MoO3_10 sample revealed that the conversion of oleic acid into methyl oleate is a thermodynamically favorable process, with a variation in the Gibbs free energy between −67.3 kJ mol–1 and 83.4 kJ mol–1 as also, the energy value of activation of 24.6 kJ mol–1, for the temperature range from 80 to 140 °C, that is, from 353.15 to 413.15 K, respectively. Meanwhile, the catalyst reuse tests resulted in percentages greater than 85%, even after the ninth catalytic cycle. Therefore, the expressive catalytic performance of the mixture of h-MoO3 and α-MoO3 (MoO3_10) phases is confirmed, associated with the synergistic effect, mainly due to the increase in the surface area and available Lewis sites of these phases.
Reduced Graphene Oxide-Substituted Nanohydroxyapatite: Rejuvenating Bone–Nerve Crosstalk with Electrical Cues in a Fragility Fracture Rat Model under Hyperglycemia
Ekta Srivastava - ,
Irfan Qayoom - , and
Ashok Kumar *
Diabetes has currently acquired the status of epidemic worldwide, and among its various pathological consequences like retinopathy and nephropathy, bone fragility fractures from diabetic osteopathy occurs in later stages and is equally destructive. Chronic hyperglycemia culminates into deteriorating microvasculature and quality of bone, making it prone to fractures. Among these, hip fractures are most common, especially in older diabetic patients apart from underlying neuropathy. Our study is an attempt to ameliorate hip fragility fracture and nerve trauma with electrical stimulation as an interface in a chronic diabetic rat model. We have fabricated reduced graphene oxide-substituted hydroxyapatite as an electroactive bone substitute and incorporated it into chitosan gelatin cryogels. The in situ reduction of graphene oxide during sintering of hydroxyapatite imparts higher potential to the fabricated composite in dealing with problem at question. The cryogels depicted optimum in vitro biocompatibility and enhanced mineralization after ectopic subcutaneous implantation in rats. The therapeutic potency of composite cryogels was evaluated in a hip fracture model with compression to the sciatic nerve in diabetic rats, mimicking the severe clinical trauma. The presence of cryogels in the femoral neck canal coupled with electrical stimulation and biochemical factors significantly improved bone regeneration in diabetic rats as depicted with microcomputed tomography analysis and histology images. The application of electrical stimulation also ameliorated the nerve trauma observed with 70% improvement in electrophysiological parameters such as the compound muscle action potential with combinatorial therapy. We therefore report the successful implication of a multitarget therapy in a chronic diabetic rat model unraveling the bone–nerve crosstalk with electroactive smart cryogels.
AlN Nanotube Decorated with Small Tin Oxide Clusters as a Novel CH4 Sensing Material
T. Shirazi Kharazi - ,
R. Safaiee *- , and
Sh. Nasresfahani
The success of carbon nanotubes has triggered a great deal of research interest in other one-dimensional nanomaterials with the aim of designing innovative nanostructures with attractive and distinctive attributes for applications in sensing gas molecules and toxic substances. In the present study, first-principles density functional theory calculations were exploited to assess the capability of the small tin oxide cluster (SnxOy)-decorated (6,0)aluminum nitride (AlN) nanotube for detecting methane(CH4) in terms of energetic, structural, and electronic properties. We found that SnxOy clusters were chemisorbed on the surface of the AlN nanotube due to the considerable adsorption energy and the notable charge transfer from the former to the latter. Further calculations demonstrate that the energy band gap and work function of the AlN nanotube were reduced in the presence of additives. Benefiting from the higher affinity of SnxOy toward the CH4 molecule, the Sn3O3-decorated AlN nanotube exhibited the greatest CH4 adsorption energy. The electrical conductivity increased as the energy band gap and effective mass decreased dramatically. Additionally, the type of Sn3O3-decorated AlN nanotube changed from a p-type semiconductor to an n-type one after adsorbing the CH4 molecule. Therefore, the Sn3O3-decorated AlN nanotube endows great promise as a thermopower-based, resistance-based, and Seebeck-effect-based CH4 sensing material.
Nonalkaline Fabrication of Al-Based Metal–Organic Frameworks with Tailored Water Sorption Properties via Polymeric Hydroxy-Aluminum Basicity Modulation
Qinyun Zhu - ,
Yi-nan Wu *- ,
Jingyi Shen - , and
Fengting Li
Metal–organic frameworks (MOFs) are porous crystalline materials composed of metallic nodes and organic ligands, demonstrating increasing potential in water harvesting in arid and semiarid regions. This study presents a nonalkaline, water-based, and scalable synthesis strategy designed to adjust the water sorption properties of aluminum-based MOFs (Al-MOFs), specifically, AlFum and MOF-303, by modifying the basicity of the metal source, polymeric hydroxy-aluminum, as an alternative. Characterizations, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analyses (TGA), confirmed the successful synthesis of Al-MOFs. The results revealed that high-basicity polymeric hydroxy-aluminum introduced additional mesoscopic intraparticle defects, interparticle voids, and hydrophilic surface sites to the primary microporous Al-MOFs. This led to an enhanced external surface area and uniformity in the particle size. Consequently, the water sorption performance of basicity-modulated Al-MOFs was significantly improved. Specifically, within the typical working humidity between 0.05 and 0.3, using polymeric hydroxy-aluminum of the highest basicity resulted in a 23% and 68% increase in water uptake for AlFum and MOF-303, respectively, achieving capacities of 0.43 and 0.37 g·g–1. Cyclic water adsorption–desorption tests further indicated the hydrolytic stability of prepared Al-MOFs. This study offers a novel approach to engineering MOF properties through metal source modulation, with important implications for applications in water harvesting and heat transfer.
Experimental-Modeling Framework for Identifying Defects Responsible for Reliability Issues in 2D FETs
Luca Panarella *- ,
Stanislav Tyaginov *- ,
Ben Kaczer - ,
Quentin Smets - ,
Devin Verreck - ,
Alexander Makarov - ,
Tom Schram - ,
Dennis Lin - ,
César Javier Lockhart de la Rosa - ,
Gouri S. Kar - , and
Valeri Afanas’ev
In this work, a self-consistent method is used to identify and describe defects plaguing 300 mm integrated 2D field-effect transistors. This method requires measurements of the transfer characteristic hysteresis combined with physics-based modeling of charge carrier capture and emission processes using technology computer aided design (TCAD) tools. The interconnection of experiments and simulations allows one to thoroughly characterize charge trapping/detrapping by/from defects, depending on their energy position. Once the trap energy distribution is extracted, it is used as input in transient TCAD simulations to reproduce the experimental hysteretic transfer characteristics. Our method is widely applicable to any 2D channel/gate stack combination. Here, it is demonstrated on FAB-integrated devices with AlOx/HfO2 gate oxide. A Gaussian-approximated defect band in the AlOx interlayer centered at a position of about 0.1 eV below the conduction band minimum of WS2 is obtained. Based on this energy position, it is concluded that aluminum interstitial and oxygen vacancies are the defects giving rise to the observed hysteresis. These defects are detrimental to the stability of the studied devices as they are easily accessible by channel carriers during on-state operation. A prominent hysteresis obtained during measurements is consistent with this conclusion.
Unveiling the Role of Filler Characteristics in Enhancing the High-Voltage Performance of Succinonitrile-Based Solid-State Lithium–Metal Batteries
Ruonan Yin - ,
Zhaohao Zhang - ,
Chuan Shi - ,
Jixiao Li - ,
Zhaoyan Luo *- ,
Jiangtao Hu - ,
Yongliang Li - ,
Hongwei Mi - ,
Chuanxin He - ,
Qianling Zhang - , and
Xiangzhong Ren *
For exploiting high-energy lithium–metal batteries, it is of utmost importance to develop electrolytes that possess exceptional ionic conductivity and an extensive electrochemical stability range. In this study, 3D PAN nanofibers and polymer electrolytes incorporating various inorganic fillers with different Lewis acid–base properties were fabricated. PAN@Al-SSE exhibits exceptional ionic conductivity (0.48 mS·cm–2 at room temperature), a high Li+ transference number (0.41), and a wide electrochemical window (5.26 V). The device is able to operate stably in Li symmetric cells for more than 1000 h under a potential of 0.03 V under a current density of 0.2 mA·cm–2. Besides, the groundbreaking technology equips high-voltage Li-LiCoO2 solid-state batteries with exceptional cycling performance (91.3% and 82.1% retention after 100 cycles at 0.2 and 1 C, respectively) at room temperature. Mechanistic studies indicate that the Lewis acid–base properties of surface fillers are instrumental and crucial to form a stable solid–electrolyte interphase layer. γ-Al2O3, in particular, with more Lewis acid sites, ensures the dissociation of LiTFSI and induces the excessive decomposition and polymerization of succinonitrile. There exists an equilibrium effect between dissociation and polymerization in a succinonitrile-based solid electrolyte, which plays a critical role in improving the manifestation of succinonitrile-based solid-state lithium cells, especially under high-voltage conditions.
Self-Powered Dye-Sensitized Solar-Cell-Based Synaptic Devices for Multi-Scale Time-Series Data Processing in Physical Reservoir Computing
Hiroaki Komatsu - ,
Norika Hosoda - , and
Takashi Ikuno *
This publication is Open Access under the license indicated. Learn More
Physical reservoir computing (PRC) using synaptic devices has attracted attention as a promising edge artificial intelligence device. To handle time-series data on various time scales, it is necessary to fabricate devices with the desired time scale. In this study, we fabricated a dye-sensitized solar-cell-based synaptic device with controllable time constants by changing the light intensity. This device showed synaptic features, such as paired-pulse facilitation and paired-pulse depression, in response to light intensity. Moreover, we found that the high computational performance of the time-series data processing task was achieved by changing the light intensity, even when the input pulse width was varied. In addition, the fabricated device can be used for motion recognition tasks. This study paves the way for realizing multiple time-scale PRC.
Surface Engineering via Rare Earth Oxide Composite Coating to Enhance the High-Voltage Stability of the LiCoO2 Cathode
Yuwei Zhao - ,
Wei Zeng - ,
Shengqi Su - ,
Jingzhe Wu - ,
Jiangnan Ke - ,
Yonggang Sun - , and
Xijie Lin *
The commercial application of high-voltage LiCoO2 (LCO) faces significant challenges due to rapid capacity decay, primarily attributed to an unstable interface and structure at deeply delithiated states. Herein, a unique rare earth oxide composite coating comprising La2O3, Y2O3, and LaYO3 has been prepared to stabilize LCO at high voltage. The synergistic effect between these rare earth oxides significantly reinforces the protective capabilities of the coating, effectively enhancing the interfacial/structural stability of LCO. When tested at 4.6 V, the coated LCO exhibits an excellent capacity retention of 94.4% after 300 cycles at 1 C. Even after an ultralong charge/discharge test of 700 cycles at 2 C, the coated LCO retains 85.2% of its initial specific capacity, which significantly outperforms the uncoated LCO (6.3%). Moreover, the coated LCO shows enhanced cycling performance at a high temperature of 45 °C, owing to the outstanding thermal stability of the La–Y–O composite. Additionally, the superior cycling stability of the coated LCO at 4.7 V, compared to the uncoated LCO, demonstrated the promising potential of the La–Y–O composite coating in improving electrochemical performance of LCO at higher cutoff voltages. These findings highlight an efficacious strategy to enhance the interfacial/structural stability of high-voltage LCO using rare earth oxides.
Macrophage Membrane-Coated Nanoparticles for the Delivery of Natamycin Exhibit Increased Antifungal and Anti-Inflammatory Activities in Fungal Keratitis
Xing Liu - ,
Yunfeng Zhang - ,
Fang Peng - ,
Cui Li - ,
Qian Wang - ,
Zhenhan Wang - ,
Liting Hu - ,
Xudong Peng - ,
Guiqiu Zhao *- , and
Jing Lin *
This study aims to explore the efficacy and safety of macrophage membrane-coated nanoparticles for the delivery of natamycin (NAT) in the therapy of fungal keratitis (FK). Macrophage membranes were isolated and identified by immunofluorescence staining (IFS). NAT was encapsulated into poly(lactic-co-glycolic acid) (PLGA). Fungal stimulated macrophage membranes (M1) or unstimulated membranes (M) were separately mixed and sonicated with PLGA nanoparticles. The biocompatible nanoparticles (PLGA-NAT, PLGA-NAT@M, and PLGA-NAT@M1) were characterized with zeta-sizer analysis, transmission electron microscopy (TEM), and Western blot. Drug encapsulation and loading efficiency and the release of NAT in the nanoparticles were detected by ultraviolet spectrophotometry. The cytotoxicity, ocular surface toxicity and irritability, and systemic safety of nanoparticles with different concentrations were assessed. In vitro, we examined the antifungal properties of the nanoparticles. The eye surface retention time, drug release, and curative effects on FK were evaluated in vitro and in vivo. IFS results showed the separation of the macrophage membrane and nucleus. The prepared nanoparticles had a typical “core–shell” structure and uniform nanometer size, and the membrane proteins were retained on the membrane allowing to exert functional effects of macrophage. The loading efficiencies of PLGA-NAT@M and PLGA-NAT@M1 were 7.6 and 6.7%, respectively. The encapsulation efficiencies of PLGA-NAT@M and PLGA-NAT@M1 were 51.2 and 41.5%, respectively. PLGA-NAT@M and PLGA-NAT@M1 could gradually release NAT and reduce the clearance of the ocular surface. Macrophage membranes enhanced the antifungal activity of PLGA-NAT. Furthermore, the membrane coated with macrophage increased the biocompatibility and decreased the corneal toxicity of nanoparticles. In vivo, PLGA-NAT@M1 significantly alleviated the severity of FK. In vitro, PLGA@M and PLGA@M1 reduced the protein levels of inflammatory cytokines after fungal stimulation. The prepared PLGA-NAT@M1 has good physical properties and biosafety. It could evade ocular surface clearance, release NAT gradually, and achieve high antifungal and anti-inflammatory efficiencies to FK. Macrophage membrane-coated nanoparticles clinically have high application potential to the treatment of FK.
A Discovery of Pressure-Induced New Semiconductor Electronic Phase Transitions by DFT Calculations: Introducing a Glimpse of a Novel Semiconductor Family
Yibo Sun - ,
Bohan Cao - ,
Shi Chen - ,
Xinwei Wang - ,
Defang Duan - ,
Fubo Tian *- , and
Tian Cui *
This study introduces a discovery of pressure-induced new semiconductor electronic phase transitions. A novel semiconductor family that exhibits pressure-induced nonmonotonic changes in band gaps was found and meets the definition of phase transitions, challenging the traditional understanding of linear and monotonic band gap modification through pressurization. Our findings suggest a complex interplay of atomic spacing and electron orbital contributions under varying pressure conditions, resulting in the variation of band gaps. This behavior, which includes three distinct steps: first, narrowing, second, broadening, and third, narrowing again and ultimately metalizing; some compounds could bypass step 1, has potential applications in piezoelectric and semiconductor technologies. We propose two new semiconductor electronic phase transitions (SEPT) associated with specific inflection points in the pressure-dependent band gap curve. Our results open avenues for further research into the electronic properties of crystals under high pressure, with the ultimate goal of uncovering the more profound physical principles governing these phenomena.
ZnO Nanowall Network-Based Tactile/Gesture Sensors and Prediction with Machine Learning
Bikash Baro - ,
Kavit Shah - ,
Kavan Hiren Shah - ,
Mohendra Roy - , and
Sayan Bayan *
In low-dimensional material systems, augmented physical and chemical properties may be witnessed through a unique morphological evolution. Here, we report the development of an optimized nanowall network of ZnO for the fabrication of a flexible single-electrode triboelectric nanogenerator (STENG)-based tactile and gesture sensors. The chemically grown nanowall network with an adequate pore area endows superior triboelectric output (current ∼0.6 μA and power ∼20 μW/cm2) by offering an optimum surface area and dielectric constant for pressure sensing applications. The rational comparison of the triboelectric properties of nanowall and nanorod structures of ZnO reveals that the higher surface area offered by the hollow walls leads to superior output characteristics. The demonstration of pressure sensitivity of the STENG ∼1 V/N is promising for self-powered tactile sensing applications. The array of STENG sensors, when attached to a user hand, generates distinguishable signals while holding objects of varying curvature and mass. Again, the observation of sensitivity of ∼0.1 V per degree during finger movement activity indicates the gesture sensing ability of the nanowall-based TENG system, facilitating sign language expression through the movement of fingers. Further, the generated electrical signals during tactile and gesture sensing can be classified and recognized through the deployment of machine learning (ML) techniques. In fact, the implementation of Random Forest and K-Nearest Neighbor models has offered an accuracy of 96% while recognizing the output signals generated by the sensor arrays. The demonstration of superior sensing characteristics with the optimized nanowall network may be advantageous in innovating prototype sensors for the differently abled people to distinguish or classify objects on the basis of material, morphology, and mass during their regular activities.
Transparent (Ni,Au)/ZnO:Al-Based Ohmic Contacts to p-Type GaN as an Insight into the Role of Ni and Au in Standard p-Type GaN Contacts
Aleksandra Wójcicka - ,
Zsolt Fogarassy - ,
Tatyana Kravchuk - ,
Cecile Saguy - ,
Eliana Kamińska - ,
Piotr Perlin - ,
Szymon Grzanka - , and
Michał Adam Borysiewicz *
In this work, Ni/ZnO:Al and Au/ZnO:Al structures are proposed as efficient ohmic contacts to p-GaN. Through a careful selection of deposition parameters and annealing environment, we not only achieve the formation of high-quality ohmic contacts but also gain insights into the interfacial reactions, enhancing the understanding of conventional Ni/Au contact formation on p-GaN. In particular, the notion that the presence of NiO at the interface is enough for an ohmic contact to form is challenged by showing that in fact it has to be NiO formed at the interface from metallic Ni and additional oxygen. An Au-based ohmic contact is also presented, and its formation mechanism is explained, contrary to popular knowledge that Au does not form an ohmic contact with p-GaN. The obtained contacts are low resistivity, with contact resistances of 4.77 × 10–3 Ω·cm2 and 3.34 × 10–3 Ω·cm2 for Au-based and Ni-based ones, respectively. What is also important is that we show these oxide-based contacts with metallic interlayers give lower series resistances in simplified diode structures than a standard Ni/Au-based contact, making them promising for optoelectronic devices.
Construction of Ordered and Fast Lithium Ion Channels in Gel Electrolytes for Li-SPAN Batteries
Chenran Hao - ,
Huichao Lu - ,
Jiqiong Liu - ,
Huiming Zhang - ,
Xirui Kong - ,
Jun Yang - ,
Yanna Nuli - , and
Jiulin Wang *
As one of the most promising battery systems, the lithium sulfur battery is expected to be widely used in fields of high energy density demands. Owing to the unique solid–solid conversion mechanism, there is no shuttle effect for the Li-SPAN (sulfurized polyacrylonitrile) battery. However, the compatibility between Li anode and carbonate electrolyte has not been resolved, which prevents the SPAN from practical applications. Herein, an organic–inorganic gel carbonate electrolyte is proposed to stabilize interphases and structures of both the anode and cathode, where polyimide (PI) is used for electrolyte gelation, which can assist in the uniform distribution of inorganic components at the electrolyte interface. Furthermore, ZnS nanodots loaded on two-dimensional MoS2 flakes provide abundant Li-ion diffusion paths, improve the transfer kinetic of Li ions, and induce uniform nucleation and deposition of Li. This gel electrolyte ensures Li symmetric cells a long-term cycle life of more than 900 h under the condition of deep lithium plating/stripping at 5 mAh cm–1. Li∥Cu cells exhibit a prolonged lifespan of 800 h with a CE of 98.3%. Furthermore, the Li-SPAN battery shows stability of more than 850 cycles, with the capacity retention of 85.1%. This work provides an approach for high-energy Li-SPAN batteries with carbonate-based electrolytes.
Synthesis of Monodisperse and Discrete Ultra-High Nickel LiNi0.97Co0.02Mn0.01O2 Octahedral Single Crystals via Single Crystal Intermediates for Li-Ion Batteries
Seung Hyun Choi - ,
Soon-Kie Hong - ,
Byunghyun Yun - ,
Junho Jung - ,
Chanhyun Baik - ,
Kanghyeon Kim - , and
Kyu Tae Lee *
Micrometer-sized single crystal cathodes have garnered significant interest as promising cathode materials for lithium-ion batteries due to their ability to reduce surface area exposure to electrolytes and suppress side reactions, thereby enhancing electrochemical performance. One of the challenging issues with single crystal cathode materials is synthesizing monodisperse and discrete single crystals rather than agglomerated quasi-single crystals. However, conventional solid-state synthesis of most single crystals results in severe agglomeration and cation mixing, as it requires high temperatures to promote particle growth to several micrometers. In this study, a novel morphology-conserving reaction strategy that employs octahedron single crystal intermediates is introduced to synthesize discrete, monodisperse LiNi0.97Co0.02Mn0.01O2 octahedron single crystals. This scalable and cost-effective approach involves using rock-salt Ni0.97Co0.02Mn0.01O1+x octahedrons as single crystal intermediates, which are transformed in unreactive unary lithium salt melts (LiCl and Li2SO4) from spherical Ni0.97Co0.02Mn0.01(OH)2 obtained via coprecipitation. These intermediates are then subjected to a stoichiometric amount of Li precursor in a conventional solid-state synthesis to produce layered LiNi0.97Co0.02Mn0.01O2. This process is a morphology-conserving lithiation reaction, leading to the formation of discrete and monodisperse LiNi0.97Co0.02Mn0.01O2 octahedron single crystals. The resultant LiNi0.97Co0.02Mn0.01O2 single crystals demonstrate superior electrochemical performance, including stable capacity retention over 150 cycles, which surpasses that of typical quasi-single crystals produced through conventional methods. This is attributed to negligible crack formation during cycling, in contrast to significant cracking observed in conventional quasi-single crystals. This implies that single-crystal forms are preferred over agglomerated quasi-single crystal forms for enhancing cycle performance. These findings provide valuable insights into the industrial synthesis of discrete and monodisperse ultrahigh-nickel oxide cathode materials.
Modulating the Electrical Transport in Superconducting NbC Crystals by Fractal Morphology
Yunqi Fu - ,
Su Sun - ,
Meng Hao - ,
Qiang Wang - ,
Zhibo Liu - ,
Chuan Xu *- ,
Hui-Ming Cheng - ,
Wencai Ren *- , and
Ning Kang *
The self-similar fractal morphology mediated by nonequilibrium processes is widely observed in low-dimensional materials grown by various techniques. Understanding how these fractal geometries affect the physical and chemical properties of materials and devices is crucial for both fundamental studies and various applications. In particular, the interplay between superconducting phase fluctuations and disorder can give rise to intriguing phenomena depending on the dimensionality. However, current experimental studies on low-dimensional superconductors are limited to two- and one-dimensional systems, leaving fractional dimensional systems largely unexplored. Here, we use chemical vapor deposition to successfully synthesize ultrathin NbC crystals with a well-defined fractal geometry at the nanoscale. By performing electrical transport measurements, we find that both the superconducting and normal-state properties are strongly affected in the fractal samples, where the intrinsic and geometric disorder is induced. In contrast to the 2D crystal, the fractal NbC crystals show a significant low-temperature resistive upturn before the onset of superconducting transition, which can be attributed to the disorder-enhanced electron–electron interaction effect. From transport data analysis, we demonstrate that the superconducting transition in NbC is correlated to the strength of disorder and the fractional dimensions, revealing that nanoscale fractal structures can significantly modify the electronic properties of low-dimensional superconductors. Our work paves the way for the explorations of mesoscopic transport and intriguing superconducting phenomena in fractional dimensions.
Bioprinting PDLSC-Laden Collagen Scaffolds for Periodontal Ligament Regeneration
Isaac J. de Souza Araújo - ,
Rachel S. Perkins - ,
Mohamed Moustafa Ibrahim - ,
George T.-J. Huang *- , and
Wenjing Zhang *
This publication is Open Access under the license indicated. Learn More
Periodontitis and severe trauma are major causes of damage to the periodontal ligament (PDL). Repairing the native conditions of the PDL is essential for the stability of the tissue and its interfaces. Bioprinting periodontal ligament stem cells (PDLSCs) is an interesting approach to guide the regeneration of PDL and interfacial integration. Herein, a collagen-based bioink mimicking the native extracellular matrix conditions and carrying PDLSCs was tested to guide the periodontal ligament organization. The bioink was tested at two different concentrations (10 and 15 mg/mL) and characterized by swelling and degradation, microstructural organization, and rheological properties. The biological properties were assessed after loading PDLSCs into bioinks for bioprinting. The characterization was performed through cell viability, alizarin red assay, and expression for ALP, COL1A1, RUNX2, and OCN. The in vivo biocompatibility of the PDLSC-laden bioinks was verified using subcutaneous implantation in mice. Later, the ability of the bioprinted PDLSC-laden bioinks on dental root fragments to form PDL was also investigated in vivo in mice for 4 and 10 weeks. The bioinks demonstrated typical shear-thinning behavior, a porous microstructure, and stable swelling and degradation characteristics. Both concentrations were printable and provided suitable conditions for a high cell survival, proliferation, and differentiation. PDLSC-laden bioinks demonstrated biocompatibility in vivo, and the bioprinted scaffolds on the root surface evidenced PDLSC alignment, organization, and PDLSC migration to the root surface. The versatility of collagen-based bioinks provides native ECM conditions for PDLSC proliferation, alignment, organization, and differentiation, with translational applications in bioprinting scaffolds for PDL regeneration.
Improving Bulk and Interfacial Lithium Transport in Garnet-Type Solid Electrolytes through Microstructure Optimization for High-Performance All-Solid-State Batteries
Young-Geun Lee - ,
Seonghwan Hong - ,
Bonian Pan - ,
Xinsheng Wu - ,
Elizabeth C. Dickey *- , and
Jay F. Whitacre *
This publication is Open Access under the license indicated. Learn More
Garnet-type Li6.4La3Zr1.4Ta0.6O7 (LLZTO) is regarded as a highly competitive next-generation solid-state electrolyte for all-solid-state lithium batteries owing to reliable safety, a wide electrochemical operation window of 0–6 V versus Li+/Li, and a superior stability against Li metal. Nevertheless, insufficient interface contacts caused by pores, along with Li dendrite growth at these voids and grain boundary regions, have hindered their commercial application. Herein, we suggest a method to produce high-quality LLZTO using LiAlO2 (LAO) as a chemical additive that leads to an improved microstructure with larger grain size (∼25 μm), a high relative density (∼96%), lower porosity (∼3.7%), and continuous secondary phases in grain boundary regions. This improved structure results in (i) improved Li-ion conductivity and enhanced interfacial resistance between Li metal and LLZTO by a denser structure with fewer pores and (ii) suppression of Li dendrite penetration in the electrolyte by secondary phases in grain boundary regions.
Scattering-Free and Fast Response Polymer Brush-Stabilized Liquid Crystals Beam Steering Using Surface-Initiated Polymerization Technique
Zhenyao Bian - ,
Zi Wang - ,
Hongbo Lu *- , and
Miao Xu *
Nonmechanical fast response optical beam steering technology is increasingly essential for telecommunications, imaging systems, optical sensing, displays, and military applications. Polymer network liquid crystal (PNLC) beam steering can achieve submillisecond response times but faces limitations due to scattering issues arising from the refractive index mismatch between the polymer network and the liquid crystals (LCs). In this article, we demonstrate a scattering-free, fast-response LC beam steering by using polymer brushes to stabilize the gradient refractive index. First, the initiator is incorporated into the alignment layer and the monomer is mixed into the LC layer. Surface-initiated polymerization (SIP) is then employed to grow the polymer brushes exclusively on the substrate’s surface, thus confining the polymer network’s growth to the LC bulk and reducing interfacial scattering. For polymer brush stabilized liquid crystal (PBSLC) beam steering device with a period size of 225 μm and a cell gap of 7.2 μm, the average transmission rate reaches 88% in the visible light spectrum with a haze value of only 6.91. The steering angle is 0.16, and the diffraction efficiency is 80.3%. When a voltage of 35 Vrms is applied, the primary energy can be tuned to the zeroth order, with a response time close to 1 ms. By cascading two PBSLC beam steering devices with opposite steering directions, the primary energy of the beam can be adjusted between zeroth, +1, and −1 order. This method requires only a UV light source, a precision displacement stage, a power supply, and a mask, avoiding the need for expensive equipment and complex electrode fabrication. By adjustment of the phase change period, step width, and number of steps during fabrication, the steering angles and diffraction efficiency of the PBSLC beam steering device can be easily controlled, highlighting its significant potential for industrial production.
A Flexible Organomagnetic Single-Layer Composite Film with Built-In Multistimuli Responsivity
Amos Bardea *- ,
Adam Cohen - ,
Alexander Axelevitch - , and
Fernando Patolsky
Materials possessing multiple properties and functionalities, that can be controlled or modulated by external stimuli, are a central focus of current research in materials sciences due to their potential to significantly enhance various future technological applications. Herein, we report a significant advancement in this field through the development of a smart, multifunctional organomagnetic composite material. By utilizing a thin layer of polydimethylsiloxane (PDMS) and polypyrrole (PPy) precursors, doped with nickel nanoparticles (NiNPs), we have created an innovative organomagnetic, PDMS/PPy/NiNPs (PPN), single-layer composite film that displays multistimuli responsivity. The study presents the first demonstration of a multifunctional flexible, three-component film structure integrating the structural and flexible PDMS component, together with a conductive polymer component and metal-based nanoparticles into a single-layer design, which displays enhanced and unprecedented responsivity properties against multiple different stimuli. Unlike typical stacked multilayered structures, that exhibit one or two functionalities at most, this novel configuration exhibits multiple functionalities, including magnetoresistance, mechanical stress response, piezoresistivity, and temperature change sensitivity. The as-prepared film demonstrates notable magnetoresistance responsivity, with a relative electrical resistance, ΔR/R0, changing under a weak magnetic field and under ambient conditions. The significance of our study lies in the film’s versatility, stability, and sensitivity, especially within the physiological temperature range, making it highly relevant for future biomedical applications. Furthemore, the film’s sensitivity to mechanical deformation reveals an impressive piezoresistance behavior. Unlike existing multilayer architectures of higher complexity, our single-layer thin film offers a simpler, more flexible, and reliable solution with a broad range of stimuli-sensing capabilities. The significance of this novel multiresponsive composite material is underscored by the growing demand for advanced materials in biomedical devices, magnetic switches, sensors, electronic skin, transistors, and organic spintronic devices. These promising organomagnetic self-standing layers provide a robust platform for future technological innovations.
Supramolecular Self-Assembled Hydrogel for Antiviral Therapy through Glycyrrhizic Acid-Enhanced Zinc Absorption and Intracellular Accumulation
Chang Lu - ,
Chenqi Chang - ,
Yu Zheng - ,
Jianjian Ji - ,
Lili Lin - ,
XiuZhen Chen - ,
Wei Chen - ,
Linwei Chen *- ,
Zhipeng Chen *- , and
Rui Chen *
Respiratory syncytial virus (RSV) is a common pathogen that causes respiratory infections in infants and children worldwide, significantly impacting hospitalization rates in this age group. Zinc ions are considered to have broad-spectrum antiviral potential against RNA viruses, including RSV. However, poor organism absorption and low intracellular accumulation of zinc require repeated high-dose supplementation, which may lead to unnecessary toxic side effects. In this research, a Zn2+-mediated glycyrrhizinic acid (GA)-based hydrogel (ZnGA Gel) was introduced and potentially developed to be a clinically available drug candidate for RSV therapy. ZnGA Gel was fabricated based on the cooperation of two potential RSV inhibiting molecules (Zn2+ and GA), where Zn2+ promoted self-assembly of GA and reduced its gel concentration and GA promoted zinc absorption and distribution in lung tissue in vivo. The facile construction of supramolecular hydrogel by the self-assembled coordination complex made it an injectable, temperature-sensitive, and pH-responsive controlled-release drug delivery for Zn2+. Most importantly, GA was observed to enhance organism absorption and intracellular accumulation of Zn2+ and was identified as a zinc ionophore for the first time. GA can colonize on the cell membrane and disturb cell membrane potential, resulting in an enhanced cell membrane permeability. In the presence of GA, more than 4.7-fold increasing Zn2+ concentrations materialized in the intracellular cytoplasm, compared to Zn2+ alone administration. This intracellular Zn2+ accumulation directly boosted the antiviral activities through improved inhibition of RSV replication-associated proteins and significantly inhibited RSV replication. Oral administration of ZnGA Gel on the RSV-infected mice model achieved an ideal therapeutic effect by effectively lowering viral load in the lungs, alleviating lung injury symptoms, and reducing inflammatory cell infiltration at pathological sites. The mechanism involved the inhibition of RSV replication-related proteins, aligning with our in vitro results. Additionally, ZnGA Gel had demonstrated biocompatibility, and reasonable supplementation of zinc was acceptable and effective for infants and children in clinical practice. Hence, the ZnGA Gel developed by us holds promise as an effective anti-RSV medicine in the future.
Oriented Alginate-Poly(vinyl alcohol) Electrospun Nanofibers for Multimodal Sensing and Gesture Language Recognition
Yu Fu - ,
Chen Yang - ,
Ye Tian *- ,
Boqiang Zhang *- ,
Zhenshuai Wan - ,
Kun Zhang - ,
Shuangkun Wang - ,
Guoxing Jiang - ,
Wei Liu - , and
Ronghan Wei *
Flexible nanofiber sensors have gained substantial attention in extending application scenarios owing to their desirable lightweight, comfort, and breathability. Nevertheless, disorder and uneven dimension issues of nanofibers are the leading concerns in their multifunctional response, which often leads to erratic response signals as well as poor linearity. In this work, a high-performance oriented nanofiber film with a three-dimensional network consisting of alginate sodium, poly(vinyl alcohol), and poly(ethylene oxide) was successfully fabricated by a controllable directional electrospinning technique. The main properties of the nanofibers are capable of being regulated intentionally by varying the electrospinning temperature, collector rotation speed, and polymer concentrations. Based on the favorable structure orientation, the nanofiber film displays satisfied biodegradability and high mechanical strength (575.1 MPa). Being integrated with modified magnetic particles, the sensors not only display a fast response speed, high magnetic sensitivity, and exceptional recoverability in response to magnetic fields but also show favorable sensitivities and reliable long-term durability under mechanical excitations. As a wearable sensor, it can accurately perceive the physiological signals generated by the human body in real-time. Furthermore, with the assistance of a convolutional neural network model, a gesture language recognition system is developed by integrating multiple sensors to realize a high recognition accuracy (∼99.08%). This study provides a feasible strategy to manufacture high-performance multimodal sensors for wearable human–machine interaction applications.
October 27, 2024
Construction of an Innovative Nanogel and Its Applications for Achieving Chemo-Immunotherapy of Tumors
Sibei Wang - ,
Fan Nie - ,
Zhen Lin - ,
Ruyu Cao - ,
Jing Xu *- , and
Yuanqiang Guo *
Malignant tumors, also known as cancers, are a global public health problem. Nanogels are promising carriers for the delivery of anticancer medicines. Therefore, based on the unique microenvironment of tumor cells and the advantages of nanogels, a simple and economical one-pot synthesis method was designed to construct natural polysaccharide-based redox-responsive nanogels (LDD NGs). The enhanced permeability and retention (EPR) effect enriched LDD NGs in tumor cells, which then rapidly collapsed and released the natural antitumor drug diosgenin (DG) and the natural polysaccharide lentinan (LNT) via the depletion of a high level of reduced glutathione (GSH) in tumor cells, resulting in a synergistic therapeutic effect of chemotherapy and immunotherapy. In vivo antitumor experiments showed that LDD NGs could inhibit the proliferation and metastasis of the A549 lung cancer cells. Further studies indicated that LDD NGs could increase the production of ROS and induce apoptosis of A549 cells. In addition, LNT released from LDD NGs could promote the proliferation of dendritic cells, increase the production of NO, and upregulate the expressions of the costimulatory molecules CD40, CD80, CD86, and MHC-II. The construction of LDD NGs was a novel drug synthesis approach that could provide fresh ideas for the development of polysaccharide-based redox-responsive drug delivery systems.
October 26, 2024
Mitigation of Cisplatin-Induced Nephrotoxicity and Augmentation of Anticancer Potency via Tea Polyphenol Nanoparticles’ Codelivery of siRNA from CRISPR/Cas9 Screened Targets
Lingjiao Li - ,
Chengyao Feng - ,
Wenchao Zhang - ,
Lin Qi - ,
Binfeng Liu - ,
Hua Wang - ,
Chenbei Li - ,
Zhihong Li - ,
Chao Tu *- , and
Wenhu Zhou *
Cisplatin, a frontline chemotherapeutic agent against cancer, faces challenges in clinical application due to significant toxicities and suboptimal efficacy. Renal toxicity, a dose-limiting factor of cisplatin, results from multifactorial processes including cisplatin-induced cellular pyroptosis, oxidative damage, and inflammatory responses. Our findings reveal that Tea Polyphenols Nanoparticles (TPNs) derived from Epigallocatechin gallate (EGCG) effectively could address these diverse mechanisms, comprehensively alleviating cisplatin-induced nephrotoxicity. Leveraging TPNs as carriers, chemical conjugation enables the encapsulation of tetravalent cisplatin prodrug, extending its systemic half-life, enhancing tumor tissue accumulation, while simultaneously mitigating renal toxicity. Concurrently, employing a CRISPR/Cas9 kinase library, we identified CSNK2A1 as a target sensitizing tumor cells to cisplatin, enabling specific siRNA sequences to augment cisplatin susceptibility, thereby minimizing the dosage requirement. Benefiting from the versatile carrier properties of TPNs to codeliver cisplatin prodrug and anti-CSNK2A1 siRNA, we developed a codelivery system, Pt-TPNs/siRNA. Pt-TPNs/siRNA not only enhances the anticancer effects but also mitigates cisplatin-induced renal toxicity, achieving efficacy while reducing toxicity. Mechanistic and safety assessments of these nanoparticles were conducted at both cellular and animal levels, opening new avenues for improved clinical utilization of cisplatin.
High-Performance Ultra-Broadband Photodetector Based on Fe3O4/CrSiTe3 Heterostructures
Qilong Wang - ,
Xuemin Zhang - ,
Suofu Wang *- ,
Yanwei Wu - ,
Xiangfei Wei - ,
Tao Han - ,
Feng Li - ,
Lei Shan *- , and
Mingsheng Long *
Photodetectors based on advanced materials with a broad spectral photoresponse, high sensitivity, huge integration ability, room-temperature operation, and stable environmental stability are highly desired for diversified applications of imaging, sensing, and communication. Herein, a high-performance ultra-broadband photodetector based on an ultrathin two-dimensional (2D) Fe3O4 nanoflake heterostructure with high sensitivity was designed. The photodetector response light was from visible 405 nm to long-wave infrared (LWIR) 10.6 μm in ambient air. The competitive performances, including a high photoresponsivity (R) of 182.8 A W–1, fast speed with the rise time τr = 8.8 μs, and decay time τd = 4.1 μs, were demonstrated in the visible range. Notably, the device exhibits an excellent uncooled LWIR detection ability, with a high R of 1.4 A W–1 realized at a 1.5 V bias. In the full spectral range, the noise equivalent power is lower than 0.79 pW Hz–1/2, and specific detectivity (D*) is higher than 4.9 × 108 cm Hz1/2 W–1 in ambient air. This work provides alternative ultrathin 2D materials for future infrared optoelectronic devices.
Hollow Magnetic Nanocarrier-Based Microrobot Swarms for NIR-Responsive Targeted Drug Delivery and Synergistic Therapy
Xiaobo Chen - ,
Qinyi Cao - ,
Zixian Liang - ,
Liping Huang - ,
Jizhuang Wang - , and
Yanping Hu *
Nanocarriers are frequently used for drug delivery due to their large surface area, biocompatibility, and photothermal effects. However, they face the problem of premature drug leakage during drug transport. To address this challenge, we developed near-infrared light (NIR)-responsive hollow magnetic nanocarriers (HMC) by incorporating a chitosan-based molecular valve onto hollow magnetic nanocarriers (CHMC) to enable NIR-triggered drug release. Despite this advancement, this material still encounters the challenge of inadequate targeting. Recognizing the efficacy of magnetically driven micro/nanorobot swarms in remote wireless control, targeted motion, and efficient transport, we merged CHMC with magnetically controlled micro/nanorobot swarms. We evaluated their performance under programmable magnetic fields, which can be precisely controlled in biological fluid and directed toward targeting cells. Additionally, they demonstrated the ability to execute a responsive drug release under NIR irradiation. Ultimately, we confirmed their capacity for targeted delivery, responsive drug release, and photothermal therapy for liver cancer treatment in vivo. This approach heralds new possibilities for responsive drug therapy facilitated by micro/nanorobot swarms, offering promising advancements in medical treatment.
Synergistic Interaction of Strongly Polar Zinc Selenide and Highly Conductive Carbon Nanoframeworks Accelerates Redox Kinetics of Polysulfides
Jie Yu - ,
Rong Yang *- ,
Yun Yang - ,
Chaojiang Fan - ,
Jiabin Liu - ,
Bing Ren - ,
Yinglin Yan - ,
Lisheng Zhong - , and
Yunhua Xu
Lithium–sulfur batteries (LSBs) have become strong competitors in secondary battery systems because of their superior theoretical capacity and energy density. However, due to the serious shuttle effect of soluble long-chain lithium polysulfides (LiPSs) and the slow solid–solid reaction kinetics, LSBs face some specific challenges, such as a short cycle life and low rate performance. The introduction of selenide/carbon composites derived from zeolite imidazolate frameworks (ZIFs) into separator coatings is a direct and effective solution to the aforementioned problems. Here, a zinc selenide/carbon catalyst material (ZnSe@C) was constructed and employed to modify commercial polypropylene (PP) separators to accelerate the conversion of intermediates. The highly polar ZnSe effectively fixes the active material on the cathode side by transferring electrons between elements with LiPSs and improves the utilization rate of sulfur. Concurrently, the highly conductive carbon nanoskeleton generated following the pyrolysis of ZIF-8 ensures the rapid transfer of charges during the catalytic reaction. The prepared ZnSe@C has a large specific surface area (250.07 m2 g–1) and mesoporous ratio (78.03%), which not only enhances adsorption and catalysis but also promotes the penetration of the electrolyte and the transport of Li+. Based on this, ZnSe@C/PP separator cells exhibit a low average capacity decay rate of 0.051% per cycle after 500 cycles at 1 C.
Size-Dependent Electrostatic Adsorption of Polymer-Grafted Gold Nanoparticles on Polyelectrolyte Brushes
Ye Chan Kim - ,
Son Hoang - ,
Karen I. Winey *- , and
Russell J. Composto *
Designing a functional surface that selectively adsorbs nanoparticles based on their size and shape is essential for developing an advanced adsorption-based, postsynthesis nanoparticle separation device. We demonstrate selective adsorption of larger nanoparticles from solution onto a polyelectrolyte brush by tuning the salt concentration. Specifically, a positively charged polyelectrolyte brush is created by converting pyridine groups of poly(2-vinylpyridine) to n-methylpyridinium groups using methyl iodide. The adsorption kinetics and thermodynamics of poly(ethylene glycol)-grafted, negatively charged gold nanoparticles (diameters of 12 and 20 nm) were monitored as a function of salt concentration. In a salt-free solution, the polyelectrolyte brush adsorbs gold nanoparticles of both sizes. As the salinity increases, the areal number density of adsorbed nanoparticles monotonically decreases and becomes negligible at high salinity. Interestingly, there is an intermediate range of salt concentrations (i.e., 15–20 mM of NaCl) where the decrease in nanoparticle adsorption is more pronounced for smaller particles, leading to size-selective adsorption of the larger nanoparticles. As a further demonstration of selectivity, the polyelectrolyte brush is immersed in a binary mixture of 12 and 20 nm nanoparticles and found to selectively capture larger particles with ∼90% selectivity. In addition, the size distribution of as-synthesized gold nanoparticles, with an average diameter of 12 nm, was reduced by selectively removing larger particles by exposing the solution to polyelectrolyte brush surfaces. This study demonstrates the potential of a polyelectrolyte brush separation device to remove larger nanoparticles by controlling electrostatic interactions between polymer brushes and particles.
Mechanical and Dimensional Stability of Gelatin-Based Hydrogels Through 3D Printing-Facilitated Confined Space Assembly
Heng Li Chee - ,
Yashaaswini M - ,
Jaedeok Kim - ,
Jing Wen Koo - ,
Ping Luo - ,
M. Faris H. Ramli - ,
Jennifer L. Young - , and
FuKe Wang *
Hydrogels have emerged as promising biomaterials for tissue regeneration; yet, their inherent swelling can cause deformation and reduced mechanical properties, posing challenges for practical applications in biomedical engineering. Traditional methods to reduce hydrogel swelling often involve complex synthesis procedures with limited flexibility. Inspired by nature’s efficient designs, we present here the approach to improve hydrogel performance using 3D printing-assisted microstructure engineering. By utilizing polymerization-induced phase separation of hydrogel from copolymerization of gelatin methacrylate and hydroxyethyl methacrylate (poly(GelMA-co-HEMA)) in the confined space during vat photopolymerization (VPP) 3D printing, we replicate the cuttlebone-like microstructure of hydrogels with enhanced mechanical properties and swelling resistance. We demonstrate here a 4-fold increase in elastic modulus compared to bulk polymerization of poly(GelMA-co-HEMA), together with improved mechanical and dimensional stability. This method offers promising opportunities for practical biomedical and tissue engineering applications, overcoming previous limitations in the design and performance.
October 25, 2024
Site-Selective Nanowire Synthesis and Fabrication of Printed Memristor Arrays with Ultralow Switching Voltages on Flexible Substrate
Luca De Pamphilis - ,
Sihang Ma - ,
Abhishek Singh Dahiya - ,
Adamos Christou - , and
Ravinder Dahiya *
This publication is Open Access under the license indicated. Learn More
Large area electronics (LAE) with the capability to sense and retain information are crucial for advances in applications such as wearables, digital healthcare, and robotics. The big data generated by these sensor-laden systems need to be scaled down or processed locally. In this regard, brain-inspired computing and in-memory computing have attracted considerable interest. However, suitable architectures have mainly been developed using costly and resource-intensive conventional lithography-based methods. There is a need for the development of innovative, resource-efficient fabrication routes that enable such devices and concepts. Herein, we present ZnO nanowire (NW)-based memristors on a polyimide substrate fabricated by a LAE-compatible and resource-efficient route comprising solution processing and printing technologies. High-resolution “drop-on-demand” and “direct ink write” printers are employed to deposit metallic layers (silver and gold) and a ZnO seed layer, needed for the site-selective growth of ZnO NWs via a low-cost hydrothermal method. The printed memristors show high bipolar resistance switching (ON/OFF ratio >103) between two nonvolatile states and consistent switching at ultralow voltages (all devices showed switching at amplitudes <200 mV), with the best performing device showing consistent cycled resistance switching over 4 orders of magnitude with SET and RESET voltages of about 71 and −57 mV, respectively. Thus, the presented devices offer reliable high resistance switching at the lowest reported voltage for printed memristors and prove to be competitive with many conventional nanofabrication-based devices. The presented results show the potential printed memristors technology holds for large-area, low-voltage sensing applications such as electronic skin.
Ambient Air-Synthesized CsPbBr3 Nanocrystals Coupled with TiO2 Film as an Efficient Hybrid Photoanode for Photoelectrochemical Methanol-to-Formaldehyde Conversion
Parina Nuket - ,
Tetsuya Kida - , and
Paravee Vas-Umnuay *
Due to its exceptional optoelectronic properties in the visible spectrum, cesium lead bromide (CsPbBr3) perovskite has attracted considerable attention in solar-driven organic transformations via photoelectrochemical (PEC) cells. However, the performance of the devices is adversely affected by electron–hole recombination occurring between a transparent conductive substrate, such as fluorine-doped tin dioxide (FTO), and a perovskite layer. Herein, to mitigate this issue, a compact layer of titanium dioxide (TiO2) was employed as both an electron transport layer and a hole blocking layer to diminish charge recombination while facilitating electron transfer in such perovskite material. At the oxidation peak potential of 0.70 V vs Ag/AgNO3, a hybrid photoanode of CsPbBr3/TiO2/FTO exhibited a significant increase in photocurrent density, from 15 to 41 μA/cm2, compared to a configuration without a TiO2 layer. Furthermore, the introduction of methanol as a hole scavenger in the PEC system using the hybrid photoanode facilitated the separation of electron–hole pairs, which led to an enhanced photocurrent density of 60 μA/cm2 and promoted the production of formaldehyde. High-performance liquid chromatography (HPLC) confirmed the generation of formaldehyde at a concentration of 26.69 μM with a Faradaic efficiency of 92% under an applied potential of 0.50 V vs Ag/AgNO3 for 60 min of PEC reaction. In addition to the enhanced PEC performance achieved from this hybrid photoanode, CsPbBr3 nanocrystals (NCs) in this work were synthesized by the modified one-pot method under ambient air, where highly uniform and high-purity NCs were obtained. This work signifies the groundbreaking exploration of CsPbBr3 NCs with TiO2 as a photoelectrode material in the organic-based PEC cells, which efficiently improved the interfacial charge transfer within the photoanode for the conversion of methanol to formaldehyde, marking a significant advancement in the field.
Na-Promoted Bimetallic Hydroxide Nanoparticles for Aerobic C–H Activation: Catalyst Design Principles and Insights into Reaction Mechanism
Beyzanur Erdivan - ,
Eylul Calikyilmaz - ,
Suay Bilgin - ,
Ayse Dilay Erdali - ,
Damla Nur Gul - ,
Kerem Emre Ercan - ,
Yunus Emre Türkmen *- , and
Emrah Ozensoy *
This publication is Open Access under the license indicated. Learn More
A precious metal-free bimetallic FexMn1–x(OH)y hydroxide catalyst was developed that is capable of catalyzing aerobic C–H oxidation reactions at low temperatures, without the need for an initiator, relying sustainably on molecular oxygen. Through a systematic synthetic effort, we scanned a wide nanoparticle synthesis parameter space to lay out a detailed set of catalyst design principles unraveling how the Fe/Mn cation ratio, NaOH(aq) concentration used in the synthesis, catalyst washing procedures, extent of residual Na+ promoters on the catalyst surface, reaction temperature, and catalyst loading influence catalytic C–H activation performance as a function of the electronic, surface chemical, and crystal structure of FexMn1–x(OH)y bimetallic hydroxide nanostructures. Our comprehensive XRD, XPS, BET, ICP-MS, 1H NMR, and XANES structural/product characterization results as well as mechanistic kinetic isotope effect (KIE) studies provided the following valuable insights into the molecular level origins of the catalytic performance of the bimetallic FexMn1–x(OH)y hydroxide nanostructures: (i) catalytic reactivity is due to the coexistence and synergistic operation of Fe3+ and Mn3+ cationic sites (with minor contributions from Fe2+ and Mn2+ sites) on the catalyst surface, where in the absence of one of these synergistic sites (i.e., in the presence of monometallic hydroxides), catalytic activity almost entirely vanishes, (ii) residual Na+ species on the catalyst surface act as efficient electronic promoters by increasing the electron density on the Fe3+ and Mn3+ cationic sites, which in turn, presumably enhance the electrophilic adsorption of organic reactants and strengthen the interaction between molecular oxygen and the catalyst surface, (iii) in the fluorene oxidation reaction the step dictating the reaction rate likely involved the breaking of a C–H bond (kH/kD = 2.4), (iv) reactivity patterns of a variety of alkylarene substrates indicate that the C–H bond cleavage follows a stepwise PT-ET (proton transfer-electron transfer) pathway.
Spray-Coated Ultrathin and Porous Films for Physiological Sensing and Force Detection
Tang Li - ,
Yichen Ding - ,
Chao Teng *- ,
Yan Zheng *- ,
Xiaoliang Wang *- , and
Dongshan Zhou *
Epidermal electronics employed on human skin for the long term require good breathability and nonforeign wearing. In this work, we combine phase separation and spray coating to fabricate a porous and ultrathin electrode within minutes as well as micrometer-scale porous pressure sensors. The resulting electrodes show a water vapor transmission rate of 18.4 mg·cm–2·h–1, sheet resistance of 5.2 Ω/sq, and thickness below 5 μm. The introduction of the biogel further reduced the electrode–skin impedance, which is lower than that of the commercial gel electrode, indicating that the electrode can have a high degree of conformal contact with the skin. The epidermal electronics prepared by this strategy exhibit an excellent performance in force sensing. Such results strongly prove the efficiency and practicality of the strategy.
Polydopamine Nanoformulations Induced ICD and M1 Phenotype Macrophage Polarization for Enhanced TNBC Synergistic Photothermal Immunotherapy
Siqi Geng - ,
Baoru Fang - ,
Ke Wang - ,
Fang Wang - ,
Yiqing Zhou - ,
Yike Hou - ,
M. Zubair Iqbal - ,
Yanping Chen - , and
Zhangsen Yu *
Photothermal therapy (PTT) is a promising technology that can achieve the thermal ablation of tumors and induce immunogenic cell death (ICD). However, relying solely on the antitumor immune responses caused by PTT-induced ICD is insufficient to suppress tumor metastasis and recurrence effectively. Fortunately, multifunctional nanoformulation-based synergistic photothermal immunotherapy can eliminate primary and metastatic tumors and inhibit tumor recurrence for a long time. Herein, we select polydopamine (PDA) nanoparticles to serve as the carrier for our nanomedicine as well as a potent photothermal agent and modulator of macrophage polarization. PDA nanoparticles are loaded with the insoluble immune adjuvant Imiquimod (R837) to construct PDA(R837) nanoformulations. These straightforward yet highly effective nanoformulations demonstrate excellent performance, allowing for successful triple-negative breast cancer (TNBC) treatment through synergistic photothermal immunotherapy. Moreover, experimental results showed that PDA(R837) implementation of PTT is effective in the thermal ablation of primary tumors while causing ICD and releasing R837, further promoting dendritic cell (DC) maturation and activating the systemic antitumor immune response. Furthermore, PDA(R837) nanoformulations inhibit tumor metastasis and recurrence and achieve M1 phenotype macrophage polarization, achieving long-term and excellent antitumor efficacy. Therefore, the structurally simple PDA(R837) nanoformulations provide cancer treatment and have excellent clinical translational application prospects.
Fabrication and High Dielectric Properties of Sandwich-Structured Ba0.6Sr0.4TiO3/Polyvinylidene Fluoride Layered Composites with Multiscale Parallel Interfaces
Shuhang Liu - ,
Xin Xu *- ,
Mingyu Peng - ,
Yiting Guo - ,
Jie Xu - , and
Feng Gao *
Ba0.6Sr0.4TiO3/polyvinylidene fluoride (BST/PVDF) dielectric functional composites have been widely used in flexible wearable devices, capacitors, and energy storage devices. In addition to the ceramic phase type, polymer matrix type, composition, and interfacial connectivity of BST/PVDF composite materials, their morphology also significantly influences their electrical characteristics. Therefore, herein, sandwich-structured BST/PVDF layered composites were designed and prepared via tape-casting processing using different types of BST fillers [i.e., formless zero-dimensional (0D)-BST, rod-like one-dimensional (1D)-BST, and plate-like two-dimensional (2D)-BST]. The microstructures and electrical characteristics of sandwich-structured BST/PVDF composites were studied in relation to the BST morphology. The effects of the internal mechanisms of different interfacial models on the breakdown strength of BST/PVDF composites were discussed. According to our findings, unlike the 0D-BST and 1D-BST powders, 2D-BST powders form multiscale parallel interfaces in sandwich-structured composites due to their unique lamella-like morphology, which enhances the breakdown strength of sandwich-structured composites. Sandwich-structured BST/PVDF composites containing 2D-BST powders exhibit good electrical characteristics with an energy storage density of 19.71 J/cm3, an energy storage efficiency of 85.3%, a dielectric constant of 30.4 (1 kHz), a dielectric loss of 0.036 (1 kHz), and a dielectric tunability of 93.2%. This study provides a method for preparing functional composites with high dielectric tunability and high energy storage characteristics.
Enhancing Superconductor Critical Temperature Prediction: A Novel Machine Learning Approach Integrating Dopant Recognition
Chengquan Zhong - ,
Yuelin Wang - ,
Yanwu Long - ,
Jiakai Liu - ,
Kailong Hu - ,
Jingzi Zhang *- ,
Junjie Chen *- , and
Xi Lin *
Doping plays a crucial role in determining the critical temperature (Tc) of superconductors, yet accurately predicting its effects remains a significant challenge. Here, we introduce a novel doping descriptor that captures the complex influence of dopants on superconductivity. By integrating the doping descriptor with elemental and physical features within a Mixture of Experts (MoE) model, we achieve a remarkable R2 of 0.962 for Tc prediction, surpassing all published prediction models. Our approach successfully identifies optimal doping levels in the Bi2–xPbxSr2Ca2–yCuyOz system, with predictions closely aligning with experimental results. Leveraging this model, we screen compounds from the Inorganic Crystal Structure Database and employ a generative approach to explore new doped superconductors. This process reveals 40 promising candidates for high Tc superconductivity among existing and hypothetical doped materials. By explicitly accounting for doping effects, our method offers a powerful tool for guiding the experimental discovery of new superconductors, potentially accelerating progress in high-temperature superconductivity research and opening new avenues for material design.
Compliant Interconnects Based on Single Micrometer-sized Metal-Coated Polymer Spheres
Van Long Huynh - ,
Knut E. Aasmundtveit - , and
Hoang-Vu Nguyen *
This publication is Open Access under the license indicated. Learn More
The rapid evolution of multifunctional electronics necessitates interconnection technologies appropriate for large dies with high-density and/or ultrafine pitch input/output pins. Existing technologies face numerous challenges, including demands for bonding equipment that can deliver extremely high force as well as thermo-mechanical stresses induced in the assembled packages due to mismatched thermal expansion of materials involved. This study proposes an approach to compliant interconnects comprising single micrometer-sized metal-coated polymer spheres, being joined to mating electrodes by sintering of Ag nano ink at low temperature (140 °C) and low pressure (∼15 mN/particle). Such an interconnection technology is expected to enhance the thermo-mechanical robustness of the assembled packages as well as be capable of high-density, ultrafine pitch interconnects. Our approach demonstrates control over conductive particles during assembly, achieving a 98% success rate in individual interconnects with a single captured particle. The use of sintered Ag not only secures free-standing particles on electrical pads (with an adhesion force above 2 μN) but also results in a 15% reduction in interconnect resistance, with measured resistance as low as 0.5 Ω, compared to interconnects without Ag ink. This method presents an alternative to metallurgical joints, particularly suited for high-density, ultrafine pitch applications, offering low bonding pressure and temperature, along with improved interconnect compliance to enhance the thermo-mechanical robustness of the packages.
Solvent Choice during Flow Assembly of Photocross-Linked Single-Chain Nanoparticles and Micelles Affects Cellular Uptake
Yen Vo - ,
Radhika Raveendran - ,
Cheng Cao - ,
Rebecca Y. Lai - ,
Miriam Lossa - ,
Henry Foster - , and
Martina H. Stenzel *
Polymeric micelles have widely been used as drug delivery carriers, and recently, single-chain nanoparticles (SCNPs) emerged as potential, smaller-sized, alternatives. In this work, we are comparing both NPs side by side and evaluate their ability to be internalized by breast cancer cells (MCF-7) and macrophages (RAW 264.7). To be able to generate these NPs on demand, the polymers were assembled by flow, followed by the stabilization of the structures by photocross-linking using blue light. The central aim of this work is to evaluate how the type of solvent affects self-assembly and ultimately the structure of the final NP. Therefore, a library of copolymers with different sequences, including block copolymers (AB, ABA, BAB), and statistical copolymers (rAB and rAC) was synthesized using PET-RAFT with A denoting poly(ethylene glycol) methyl ether acrylate (PEGMEA), B as 2-hydroxyethyl acrylate (HEA), and C as 4-hydroxybutyl acrylate (HBA). The polymers were conjugated with a quinoline derivative to enable the formation of cross-linked structures by photocross-linking during flow assembly. Using water as the dispersant for photocross-linking led to the preassembly of these amphiphilic polymers into compact SCNPs and cross-linked micelles, resulting in a quick photoreaction. In contrast, acetonitrile led to fully dissolved polymers but a low rate of the photoreaction. These intramolecularly cross-linked polymers were then placed in water to result in more dynamic micelles and looser SCNPs. Small-angle X-ray scattering (SAXS), dynamic light scattering (DLS), and size exclusion chromatography (SEC) coupled with a viscosity detector show that cross-linking in acetonitrile results in better-defined NPs with a shell rich in PEGMEA. Cross-linking in acetonitrile led to NPs with significantly higher cellular uptake. Interestingly, passive transport was identified as the main pathway for the delivery of our NPs on MCF-7 cells, confirmed by the uptake of NPs on cells treated with inhibitors and by red blood cells. This work underscored the importance of the polymer precursor’s structure and the choice of solvent during intramolecular cross-linking in determining the drug delivery efficiency and biological behavior of SCNPs.
Hydroxyapatite/Silk Fibroin Composite Scaffold with a Porous Structure and Mechanical Strength Similar to Cancellous Bone by Electric Field-Induced Gel Technology
Yun-Fei Shao - ,
Hui Wang *- ,
Yiran Zhu - ,
Yu Peng - ,
Fengjiao Bai - ,
Jun Zhang - , and
Ke-Qin Zhang *
Repair and regeneration of bone tissue defects is a multidimensional process that has been highly challenging to date. The artificial bone scaffold materials, which play a core role, still face the conflict that a biofriendly porous structure will reduce the mechanical performance and accelerate degradation. Herein, a multistage porous structured hydroxyapatite (HA)/silk fibroin (SF) composite scaffold (e-HA/SF) was successfully constructed by cleverly utilizing electric field-induced gel technology. The results indicated that the prepared e-HA/SF scaffolds possess biomimetic hierarchical porous structures with a suitable porosity similar to that of cancellous bone. The HA nanocrystals were uniformly encapsulated in the three-dimensional space of the composite scaffold, thus endowing the e-HA/SF composite scaffolds with an enhanced mechanical performance. Notably, the maximum compression stress and Young’s modulus of e-HA/SF-2 scaffolds can reach 24.66 ± 0.88 and 28.91 ± 3.19 MPa, respectively, which are equivalent to those of cancellous bone. Such mechanical performance enhancement was previously unattainable through conventional freeze-drying strategies. Moreover, the introduction of bioactive nano-HA can trigger the optimal cell response in both static and dynamic cell culture experiments in vitro. The e-HA/SF composite scaffold developed in this study can better balance the conflict between the porous structure and mechanical and degradation properties of porous scaffolds.
Demonstration of Scalable Water Splitting into H2 and O2 by a Flow-Type Photocatalysis-Electrolysis Hybrid System Using a Highly Stable Photocatalyst
Yugo Miseki *- ,
Michiko Tamano - ,
Kenta Watanabe - , and
Kazuhiro Sayama *
Water splitting via a photocatalysis-electrolysis hybrid system has been investigated as a potentially scalable and economically feasible means of producing renewable H2. However, there are no reports demonstrating a scalable system for stoichiometric water splitting using an efficient and stable photocatalyst, and the key operating conditions for efficiently driving the entire system have not been established. Herein, we address the issues required to efficiently drive the entire system of a Cs+, Fe2+, and H+ ion-modified WO3 (denoted as H-Fe-Cs-WO3) photocatalyst fixed reactor combined with a polymer electrolyte membrane (PEM)-type electrolyzer. In electrochemical H2 production using Fe2+, the current density improved as the concentration of both H+ and Fe2+ increased, and we determined the optimum conditions for a hybrid system using high concentrations of HClO4 and Fe(ClO4)3, which differ from those reported for photocatalysis alone. No performance deterioration of the H-Fe-Cs-WO3 photocatalyst was observed even after light irradiation for more than 10 000 h under strong acidic conditions. The accumulated Fe2+ ions were extremely stable and did not oxidize even when exposed to air for more than two months. As for the stepwise operation that takes advantage of the characteristics of the hybrid system, the contribution factor of the photocatalyst in the photocatalysis-electrolysis hybrid system for H2 evolution (CP@STHap) under an applied bias was estimated to be 0.24%, which is a value comparable to that of the solar-to-chemical (STC) conversion efficiency (0.31%). The efficiency difference (0.07%) corresponds to the overpotential of the electrolytic reaction and indicates that water splitting via the photocatalysis-electrolysis hybrid system proceeds efficiently at a small overpotential of 0.06 V (∼11.6 kJ mol–1).