Behavior of Methylammonium Dipoles in MAPbX3 (X = Br and I)Click to copy article linkArticle link copied!
- Sharada Govinda
- Bhushan P. Kore
- Menno Bokdam
- Pratibha Mahale
- Abhinav Kumar
- Somnath Pal
- Biswajit Bhattacharyya
- Jonathan Lahnsteiner
- Georg Kresse
- Cesare Franchini
- Anshu Pandey
- D. D. Sarma
Abstract
Dielectric constants of MAPbX3 (X = Br, I) in the 1 kHz–1 MHz range show strong temperature dependence near room temperature, in contrast to the nearly temperature-independent dielectric constant of CsPbBr3. This strong temperature dependence for MAPbX3 in the tetragonal phase is attributed to the MA+ dipoles rotating freely within the probing time scale. This interpretation is supported by ab initio molecular dynamics simulations on MAPbI3 that establish these dipoles as randomly oriented with a rotational relaxation time scale of ∼7 ps at 300 K. Further, we probe the intriguing possibility of transient polarization of these dipoles following a photoexcitation process with important consequences on the photovoltaic efficiency, using a photoexcitation pump and second harmonic generation efficiency as a probe with delay times spanning 100 fs–1.8 ns. The absence of a second harmonic signal at any delay time rules out the possibility of any transient ferroelectric state under photoexcitation.
Figure 1
Figure 1. Dielectric constant, ε′, versus temperature for selected frequencies measured on MAPbBr3 (symbol and solid lines) and CsPbBr3 (dashed lines) (a) and MAPbI3 (b). The insets in (a) and (b) show the fit to the experimental data of the dielectric constant vs temperature in the tetragonal phase of MAPbBr3 and MAPbI3, respectively.
MAPbI3 | MAPbBr3 | |
---|---|---|
C (K) | 9221 | 7080 |
ε∞ | 22 | 20 |
T* (K) | 66.2 | 50.4 |
μ (C m) | 10.23 × 10–30 | 8.51 × 10–30 |
Figure 2
Figure 2. Molecular polarization Pmol(t) in the 64 and 216 unit cell, called 4-cell and 6-cell, respectively, at 300 K starting from an unpolarized-random (R) structure and from a polarized-aligned (A) starting structure. Average values for independent-random dipoles for the same system size are indicated by the dashed lines.
system | P̅mol | σmol2 | τmol (ps) | P̅rand | σrand2 |
---|---|---|---|---|---|
2 × 2 × 2 (R) | 0.31 | 0.11 | 7 | 0.33 | 2 × 10–2 |
4 × 4 × 4 (A) | 0.27 | 0.05 | 8 | 0.12 | 2 × 10–3 |
4 × 4 × 4 (R) | 0.15 | 0.03 | 7 | 0.12 | 2 × 10–3 |
6 × 6 × 6 (R) | 0.07 | 0.02 | 5 | 0.06 | 7 × 10–4 |
The last two columns list the reference values for uncorrelated random dipoles.
Figure 3
Figure 3. Spectra of the second harmonic generated at 900 nm with an incident 1800 nm laser measured on (a) MAPbI3 and urea with a pump power of 2.84 mW, (b) MAPbBr3 with a pump power of 2.62 mW, and (c) CsPbBr3 with a pump power of 2.60 mW at a few selected delay times indicated in the legend. It can be seen that all of the spectra at different delay times overlap.
Figure 4
Figure 4. SHG efficiency of MAPbI3, MAPbBr3, and CsPbBr3 with respect to urea plotted against the delay time between the 400 nm pump and 1800 nm probe. The dashed lines drawn for reference in each panel represent the average SHG efficiency calculated for spectra before the arrival of the pump pulse. The pump powers were 2.84, 2.62, and 2.60 mW for MAPbI3, MAPbBr3, and CsPbBr3, respectively.
Experimental Section
Computational Method
Supporting Information
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.jpclett.7b01740.
Powder XRD patterns, dielectric data up to higher temperature, polynomial fits to SHG spectra, and residuals of polynomial fits (PDF)
Terms & Conditions
Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system: http://pubs.acs.org/page/copyright/permissions.html.
Acknowledgment
The authors thank the Department of Science and Technology, Government of India for support and Mr. Guru Pratheep. R. for help with SHG measurements. S.G. thanks Dr. Sumanta Mukherjee for useful discussions and acknowledges CSIR for a student fellowship. B.P.K. acknowledge UGC, India for a D.S. Kothari Postdoctoral Fellowship. M.B. and J.L. acknowledge funding by the Austrian Science Fund (FWF): P 30316-N27.
References
This article references 64 other publications.
- 1Bi, D.; Tress, W.; Dar, M. I.; Gao, P.; Luo, J.; Renevier, C.; Schenk, K.; Abate, A.; Giordano, F.; Correa Baena, J.-P. Efficient luminescent solar cells based on tailored mixed-cation perovskites Sci. Adv. 2016, 2, e1501170 DOI: 10.1126/sciadv.1501170Google ScholarThere is no corresponding record for this reference.
- 2McMeekin, D. P.; Sadoughi, G.; Rehman, W.; Eperon, G. E.; Saliba, M.; Hörantner, M. T.; Haghighirad, A.; Sakai, N.; Korte, L.; Rech, B. A mixed-cation lead mixed-halide perovskite absorber for tandem solar cells Science 2016, 351, 151– 155 DOI: 10.1126/science.aad5845Google Scholar2https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhvV2itg%253D%253D&md5=7d7494e92975225df9b665c13c82f46cA mixed-cation lead mixed-halide perovskite absorber for tandem solar cellsMcMeekin, David P.; Sadoughi, Golnaz; Rehman, Waqaas; Eperon, Giles E.; Saliba, Michael; Hoerantner, Maximilian T.; Haghighirad, Amir; Sakai, Nobuya; Korte, Lars; Rech, Bernd; Johnston, Michael B.; Herz, Laura M.; Snaith, Henry J.Science (Washington, DC, United States) (2016), 351 (6269), 151-155CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Metal halide perovskite photovoltaic cells could potentially boost the efficiency of com. silicon photovoltaic modules from ∼20 toward 30% when used in tandem architectures. An optimum perovskite cell optical band gap of ∼1.75 eV (eV) can be achieved by varying halide compn., but to date, such materials have had poor photostability and thermal stability. Here we present a highly cryst. and compositionally photostable material, [HC(NH2)2]0.83Cs0.17Pb(I0.6Br0.4)3, with an optical band gap of ∼1.74 eV, and we fabricated perovskite cells that reached open-circuit voltages of 1.2 V and power conversion efficiency of over 17% on small areas and 14.7% on 0.715 cm2 cells. By combining these perovskite cells with a 19%-efficient silicon cell, we demonstrated the feasibility of achieving >25%-efficient four-terminal tandem cells.
- 3Saliba, M.; Matsui, T.; Seo, J.-Y.; Domanski, K.; Correa-Baena, J.-P.; Nazeeruddin, M. K.; Zakeeruddin, S. M.; Tress, W.; Abate, A.; Hagfeldt, A. Cesium-containing triple cation perovskite solar cells: improved stability, reproducibility and high efficiency Energy Environ. Sci. 2016, 9, 1989– 1997 DOI: 10.1039/C5EE03874JGoogle Scholar3https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XksVSjt78%253D&md5=4a099536bf11a3c84c6e6e792d192664Cesium-containing triple cation perovskite solar cells: improved stability, reproducibility and high efficiencySaliba, Michael; Matsui, Taisuke; Seo, Ji-Youn; Domanski, Konrad; Correa-Baena, Juan-Pablo; Nazeeruddin, Mohammad Khaja; Zakeeruddin, Shaik M.; Tress, Wolfgang; Abate, Antonio; Hagfeldt, Anders; Gratzel, MichaelEnergy & Environmental Science (2016), 9 (6), 1989-1997CODEN: EESNBY; ISSN:1754-5706. (Royal Society of Chemistry)Today's best perovskite solar cells use a mixt. of formamidinium and methylammonium as the monovalent cations. With the addn. of inorg. cesium, the resulting triple cation perovskite compns. are thermally more stable, contain less phase impurities and are less sensitive to processing conditions. This enables more reproducible device performances to reach a stabilized power output of 21.1% and ∼18% after 250 h under operational conditions. These properties are key for the industrialization of perovskite photovoltaics.
- 4Yoon, H.; Kang, S. M.; Lee, J.-K.; Choi, M. Hysteresis-free low-temperature-processed planar perovskite solar cells with 19.1% efficiency Energy Environ. Sci. 2016, 9, 2262– 2266 DOI: 10.1039/C6EE01037GGoogle Scholar4https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XovFWisbs%253D&md5=01ce9e7d07653b09a26a71b42ae9c7d9Hysteresis-free low-temperature-processed planar perovskite solar cells with 19.1% efficiencyYoon, Heetae; Kang, Seong Min; Lee, Jong-Kwon; Choi, MansooEnergy & Environmental Science (2016), 9 (7), 2262-2266CODEN: EESNBY; ISSN:1754-5706. (Royal Society of Chemistry)Hysteresis-free, highly efficient and stable perovskite solar cells processed at low temps. are strongly demanded to realize flexible or perovskite-based tandem solar cells. Here, we report a hysteresis-free planar CH3NH3PbI3 perovskite solar cell with a power conversion efficiency of 19.1% using a room-temp. vacuum-processed C60 electron transport layer (ETL) without the hole blocking layer. By optimizing the thickness of the C60 layer, the highly homogeneous, uniform, and dense ETL with a thickness of 35 nm is found to not only passivate the grain boundaries and surfaces of the perovskite layer, but also enhance charge transport properties. Thus, the C60 layer deposited on perovskites eliminates the photocurrent hysteresis and improves the cell efficiency. Also, compared to the device adopting the C60 and bathocuproine (BCP) combination, the one with the C60 layer without the BCP layer shows better performance due to enhanced electron extn. properties. Furthermore, for the first time, we have demonstrated a hysteresis-free flexible perovskite solar cell using the C60 ETL on a polyethylene naphthalate (PEN) substrate with 16.0% efficiency.
- 5Baikie, T.; Fang, Y.; Kadro, J. M.; Schreyer, M.; Wei, F.; Mhaisalkar, S. G.; Graetzel, M.; White, T. J. Synthesis and crystal chemistry of the hybrid perovskite (CH3NH3)PbI3 for solid-state sensitised solar cell applications J. Mater. Chem. A 2013, 1, 5628– 5641 DOI: 10.1039/c3ta10518kGoogle Scholar5https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXmtF2isb8%253D&md5=aa26f1e37df912912faed0c8b37f757bSynthesis and crystal chemistry of the hybrid perovskite (CH3NH3)PbI3 for solid-state sensitised solar cell applicationsBaikie, Tom; Fang, Yanan; Kadro, Jeannette M.; Schreyer, Martin; Wei, Fengxia; Mhaisalkar, Subodh G.; Graetzel, Michael; White, Tim J.Journal of Materials Chemistry A: Materials for Energy and Sustainability (2013), 1 (18), 5628-5641CODEN: JMCAET; ISSN:2050-7496. (Royal Society of Chemistry)The hybrid org.-inorg. perovskite (CH3NH3)PbI3 may find application in next generation solid-state sensitized solar cells. Although this material and related perovskites were discovered many decades ago, questions remain concerning their diverse structural chem. and unusual properties. The article presents a review of previous work and provides a detailed description of the prepn., structural characterization and phys. characteristics of (CH3NH3)PbI3. The phase changes exhibited by (CH3NH3)PbI3 have been probed using variable temp. powder and single crystal x-ray diffraction, combined with differential scanning calorimetry, thermogravimetric anal. and phase contrast transmission electron microscopy. The optical band gap for (CH3NH3)PbI3 detd. by UV-visible spectroscopy was compared to values obtained from d.-of-state simulation of the electronic band structure.
- 6Butler, K. T.; Frost, J. M.; Walsh, A. Band alignment of the hybrid halide perovskites CH3NH3PbCl3, CH3NH3PbBr3 and CH3NH3PbI3 Mater. Horiz. 2015, 2, 228– 231 DOI: 10.1039/C4MH00174EGoogle Scholar6https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvVWlsr7M&md5=19cab0870a720f0bc1e1cf33dc529240Band alignment of the hybrid halide perovskites CH3NH3PbCl3, CH3NH3PbBr3 and CH3NH3PbI3Butler, Keith T.; Frost, Jarvist M.; Walsh, AronMaterials Horizons (2015), 2 (2), 228-231CODEN: MHAOBM; ISSN:2051-6355. (Royal Society of Chemistry)Org.-inorg. halide perovskites efficiently convert sunlight to electricity in solar cells. The choice of halide (Cl, Br or I) can be used to chem. tune the spectral response of the materials and the positions of the valence and conduction bands (i.e. the ionization potential and electron affinity). Here the band offsets of the methylammonium lead halides are reported, including relativistic corrections and using the Pb 1s core level as a ref. state. The binding energy of the valence band decreases monotonically down the series, primarily due to the change from 3p to 4p to 5p valence orbitals of the halide. Type I band alignments are predicted, which implies that Br and Cl secondary phases in CH3NH3PbI3 thin-films would act as barriers to charge transport in photovoltaic devices.
- 7Bokdam, M.; Sander, T.; Stroppa, A.; Picozzi, S.; Sarma, D. D.; Franchini, C.; Kresse, G. Role of polar phonons in the photo excited state of metal halide perovskites Sci. Rep. 2016, 6, 28618 DOI: 10.1038/srep28618Google Scholar7https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtFSisbrF&md5=fef5a7deb5e0c07aaa0eb7a7ba952c8bRole of Polar Phonons in the Photo Excited State of Metal Halide PerovskitesBokdam, Menno; Sander, Tobias; Stroppa, Alessandro; Picozzi, Silvia; Sarma, D. D.; Franchini, Cesare; Kresse, GeorgScientific Reports (2016), 6 (), 28618CODEN: SRCEC3; ISSN:2045-2322. (Nature Publishing Group)The development of high efficiency perovskite solar cells has sparked a multitude of measurements on the optical properties of these materials. For the most studied methylammonium(MA)PbI3 perovskite, a large range (6-55 meV) of exciton binding energies has been reported by various expts. The existence of excitons at room temp. is unclear. For the MAPbX3 perovskites we report on relativistic Bethe-Salpeter Equation calcns. (GW-BSE). This method is capable to directly calc. excitonic properties from first-principles. At low temps. it predicts exciton binding energies in agreement with the reported 'large' values. For MAPbI3, phonon modes present in this frequency range have a negligible contribution to the ionic screening. By calcg. the polarization in time from finite temp. mol. dynamics, we show that at room temp. this does not change. We therefore exclude ionic screening as an explanation for the exptl. obsd. redn. of the exciton binding energy at room temp. and argue in favor of the formation of polarons.
- 8Poglitsch, A.; Weber, D. Dynamic disorder in methylammoniumtrihalogenoplumbates (II) observed by millimeter-wave spectroscopy J. Chem. Phys. 1987, 87, 6373– 6378 DOI: 10.1063/1.453467Google Scholar8https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL1cXht1arsLo%253D&md5=f528e1c73c9b3e007ec5d7ca47650b39Dynamic disorder in methylammonium trihaloplumbates(II) observed by millimeter-wave spectroscopyPoglitsch, A.; Weber, D.Journal of Chemical Physics (1987), 87 (11), 6373-8CODEN: JCPSA6; ISSN:0021-9606.The temp.-dependent structure of cryst. methylammonium trihaloplumbates(II) CH3NH3+PbX3- (X = Cl, Br, I) as detd. by x-ray diffraction, was compared with measurements of the temp.-dependent complex permittivity at frequencies of 50-150 GHz. The dielec. measurements reveal a ps relaxation process which corresponds to a dynamic disorder of the methylammonium group in the high-temp. phases of the trihaloplumbates.
- 9Swainson, I. P.; Hammond, R. P.; Soullière, C.; Knop, O.; Massa, W. Phase transitions in the perovskite methylammonium lead bromide, CH3ND3PbBr3 J. Solid State Chem. 2003, 176, 97– 104 DOI: 10.1016/S0022-4596(03)00352-9Google Scholar9https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXovVWntro%253D&md5=949bb0a19b3c2ed6aedda78931bef434Phase transitions in the perovskite methylammonium lead bromide, CH3ND3PbBr3Swainson, I. P.; Hammond, R. P.; Soulliere, C.; Knop, O.; Massa, W.Journal of Solid State Chemistry (2003), 176 (1), 97-104CODEN: JSSCBI; ISSN:0022-4596. (Elsevier Science)The structure of phase IV of methylammonium lead bromide, CH3ND3PbBr3, is shown from Rietveld refinement of neutron powder diffraction data to be centrosym., with space group Pnma: Z = 4; a 7.9434(4), b 11.8499(5), c 8.5918(4) Å at 11 K; Rwp = 2.34% Rp = 1.81%. This corresponds to one of the pure tilt transitions, a-b+a-, commonly obsd. in perovskites. Addnl. distortions not required by pure tilting are found in the PbBr6 octahedra, and apparently the structure optimizes the H bonding between the methylammonium cation and the framework. It is likely that the lowest temp. phase of the corresponding iodide also has this structure. The structure is compared to the available data for that of other Pnma perovskites. A brief comparison to the higher temp. phases in which the methylammonium ion is disordered is given.
- 10Chi, L.; Swainson, I.; Cranswick, L.; Her, J.-H.; Stephens, P.; Knop, O. The ordered phase of methylammonium lead chloride CH3ND3PbCl3 J. Solid State Chem. 2005, 178, 1376– 1385 DOI: 10.1016/j.jssc.2004.12.037Google Scholar10https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXjvV2gs7Y%253D&md5=f164b5177ad39cf04c8b642db25495e4The ordered phase of methylammonium lead chloride CH3ND3PbCl3Chi, Lisheng; Swainson, Ian; Cranswick, Lachlan; Her, Jae-Hyuk; Stephens, Peter; Knop, OsvaldJournal of Solid State Chemistry (2005), 178 (5), 1376-1385CODEN: JSSCBI; ISSN:0022-4596. (Elsevier)The perovskite-structured compd. methylammonium lead chloride orders into a low-temp. phase of space group Pnma, in which at 80 K each of the orthorhombic axes a 11.1747(2), b 11.3552(1) and c 11.2820(1) Å is doubled with respect to the room temp. disordered cubic phase (a 5.669 Å). Crystallog. data and at. coordinates are given. The structure was solved by ab initio methods using the programs EXPO and FOX. This unusual cell basis for space group Pnma is not that of a std. tilt system. This phase, in which the methylammonium ions, are ordered shows distorted octahedra. The octahedra possess a bond angle variance of 60.663°2 and a quadratic elongation of 1.018, and are more distorted than those in the ordered phase of methylammonium lead bromide. There is also an alternating long and short Pb-Cl bond along a, due to an off-center displacement of Pb within the octahedron. Probably the most rigid unit is actually the methylammonium cation, rather than the PbCl6 octahedra, in agreement with existing spectroscopic data.
- 11G, S.; Mahale, P.; Kore, B. P.; Mukherjee, S.; Pavan, M. S.; De, C.; Ghara, S.; Sundaresan, A.; Pandey, A.; Guru Row, T. N. Is CH3NH3PbI3 polar? J. Phys. Chem. Lett. 2016, 7, 2412– 2419 DOI: 10.1021/acs.jpclett.6b00803Google Scholar11https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XpsFGqu7g%253D&md5=62073baaa71baa8a86762806be86aa9eIs CH3NH3PbI3 Polar?G, Sharada; Mahale, Pratibha; Kore, Bhushan P.; Mukherjee, Somdutta; Pavan, Mysore S.; De, Chandan; Ghara, Somnath; Sundaresan, A.; Pandey, Anshu; Guru Row, Tayur N.; Sarma, D. D.Journal of Physical Chemistry Letters (2016), 7 (13), 2412-2419CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)In view of the continued controversy concerning the polar/nonpolar nature of the hybrid perovskite system, CH3NH3PbI3, we report the first investigation of a time-resolved pump-probe measurement of the second harmonic generation efficiency as well as using its more traditional form as a sensitive probe of the absence/presence of the center of inversion in the system both in its excited and ground states, resp. Our results clearly show that SHG efficiency, if nonzero, is below the limit of detection, strongly indicative of a nonpolar or centrosym. structure. Our results on the same samples, based on temp. dependent single crystal X-ray diffraction and P-E loop measurements, are entirely consistent with the above conclusion of a centrosym. structure for this compd. in all three phases, namely the high temp. cubic phase, the intermediate temp. tetragonal phase and the low temp. orthorhombic phase. It is important to note that all our exptl. probes are vol. averaging and performed on bulk materials, suggesting that basic material properties of CH3NH3PbI3 are consistent with a centrosym., nonpolar structure.
- 12Wasylishen, R. E.; Knop, O.; Macdonald, J. B. Cation rotation in methylammonium lead halides Solid State Commun. 1985, 56, 581– 582 DOI: 10.1016/0038-1098(85)90959-7Google Scholar12https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2MXmt1CrsrY%253D&md5=7dbbb3236b992be7213270ccf60bc36eCation rotation in methylammonium lead halidesWasylishen, R. E.; Knop, Osvald; Macdonald, J. B.Solid State Communications (1985), 56 (7), 581-2CODEN: SSCOA4; ISSN:0038-1098.2H and 14N NMR spectra of the simple perovskites MeNH3PbX3 (X = Cl, Br, I) reveal the existence of several phases. In the high-temp. phase I the long spin-lattice relaxation times T1 of both nuclei and the absence of quadrupole splitting indicate extremely rapid overall reorientation of the C-N axis of the cation in a potential of cubic symmetry. In phase II of the bromide and iodide, both T1 and the small quadrupole splitting show unusual variation with temp. In the lowest-temp. phase, rotations of the C-N axis are restricted.
- 13Knop, O.; Wasylishen, R. E.; White, M. A.; Cameron, T. S.; Oort, M. J. M. V. Alkylammonium lead halides. Part 2. CH3NH3PbX3 (X = Cl, Br, I) perovskites: cuboctahedral halide cages with isotropic cation reorientation Can. J. Chem. 1990, 68, 412– 422 DOI: 10.1139/v90-063Google Scholar13https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3cXit1Ojtrg%253D&md5=5c25c736c86cf3e06a11daee3d671a41Alkylammonium lead halides. Part 2. CH3NH3PbX3 (X = chlorine, bromine, iodine) perovskites: cuboctahedral halide cages with isotropic cation reorientationKnop, Osvald; Wasylishen, Roderick E.; White, Mary Anne; Cameron, T. Stanley; Van Oort, Michiel J. M.Canadian Journal of Chemistry (1990), 68 (3), 412-22CODEN: CJCHAG; ISSN:0008-4042.MeNH3PbCl3 (I), MeNH3PbBr3 (II), and MeNH3PbI3 (III) were investigated by single-crystal x-ray diffraction, 2H and 14N NMR, adiabatic calorimetry, and other methods. I has transitions at 171.5 and 177.4 K, II at 148.4, 154.2, and 235.1 K, and III at 162.7 and 326.6 K. The resp. entropies of transition (J K-1 mol-1) are 11.0 and 5.1 for I; 8.7, 3.4, and 5.3 for II; and 16.1 and 1.9 for III. The highest-temp. phase, phase I, of each halide is cubic (Pm3m) perovskite type. The cation in phase I of I and II could not be localized in the electron d. maps; the thermal motion of the halogen atom is highly anisotropic. The ln T1(2H) vs. T-1 plots (N-deuterated samples as well as CD3NH3PbCl3) show significant departures from linearity: the temp. variation of T1(2H) in phase II of II and III can be represented by functions of the type ln T1(H) = k0 - k2T-2, which give adequate anal. representations of T1(2H) and T1(14N) in phase I as well. On cooling, phase II of II and III exhibit small quadrupole splittings QS(2H), which can be represented to a high degree of correlation by QS(2H) = k(Ttr - T)n, i.e. they appear to exhibit crit. behavior with respect to T. The 14N NMR results indicate that the C-N bond in phase I reorients in an isotropic potential at a rate approaching that of the freely rotating methylammonium ion. Below phase I this motion takes place in an increasingly anisotropic potential in phase II of II and III and is essentially arrested in phase II of I and phase III of II and III. The temp. dependence of the activation energy Ea for the cation reorientation and other aspects of the non-Arrhenius behavior are discussed, and the MeNH3PbX3 perovskites are compared with the corresponding (MeNH3)2TeX6 halides, utilizing preliminary 2H NMR results on (CD3ND3)2TeBr6. The elec. cond., between 0 and 95°, of III increases with temp. and exhibits no discontinuity at Ttr = 326.6 K; the activation energy for the conduction process is estd. as ∼0.4 eV.
- 14Onoda-Yamamuro, N.; Matsuo, T.; Suga, H. Calorimetric and IR spectroscopic studies of phase transitions in methylammonium trihalogenoplumbates (II) J. Phys. Chem. Solids 1990, 51, 1383– 1395 DOI: 10.1016/0022-3697(90)90021-7Google Scholar14https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3MXhtFahsL4%253D&md5=e87ac8ccd0e391890852451c44f992d9Calorimetric and IR spectroscopic studies of phase transitions in methylammonium trihaloplumbates(II)Onoda-Yamamuro, Noriko; Matsuo, Takasuke; Suga, HiroshiJournal of Physics and Chemistry of Solids (1990), 51 (12), 1383-95CODEN: JPCSAW; ISSN:0022-3697.Heat capacities of CH3NH3PbX3(X = Cl, Br, I) were measured at 13-300 K (365 K for the I). Two anomalies were found in the Cl and the I, and 3 in the Br. All the phase transitions were of the 1st order, although the highest temp. transitions in the Br and the I were close to 2nd order. Their temps. and entropies are given.
- 15Bakulin, A. A.; Selig, O.; Bakker, H. J.; Rezus, Y. L. A.; Müller, C.; Glaser, T.; Lovrincic, R.; Sun, Z.; Chen, Z.; Walsh, A. Real-time observation of organic cation reorientation in methylammonium lead iodide perovskites J. Phys. Chem. Lett. 2015, 6, 3663– 3669 DOI: 10.1021/acs.jpclett.5b01555Google Scholar15https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsVeqtr%252FN&md5=e2b0e1618dc96a9c16d80cf6fbf2c66bReal-Time Observation of Organic Cation Reorientation in Methylammonium Lead Iodide PerovskitesBakulin, Artem A.; Selig, Oleg; Bakker, Huib J.; Rezus, Yves L. A.; Mueller, Christian; Glaser, Tobias; Lovrincic, Robert; Sun, Zhenhua; Chen, Zhuoying; Walsh, Aron; Frost, Jarvist M.; Jansen, Thomas L. C.Journal of Physical Chemistry Letters (2015), 6 (18), 3663-3669CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)The introduction of a mobile and polarized org. moiety as a cation in 3D Pb-iodide perovskites brings fascinating optoelectronic properties to these materials. The extent and the time scales of the orientational mobility of the org. cation and the mol. mechanism behind its motion remain unclear, with different exptl. and computational approaches providing very different qual. and quant. description of the mol. dynamics. Ultrafast 2D vibrational spectroscopy of methylammonium (MA) Pb iodide was used to directly resolve the rotation of the org. cations within the MAPbI3 lattice. The results reveal 2 characteristic time consts. of motion. Using ab initio mol. dynamics simulations, the authors identify these as a fast (∼300 fs) wobbling-in-a-cone motion around the crystal axis and a relatively slow (∼3 ps) jump-like reorientation of the mol. dipole with respect to the iodide lattice. The obsd. dynamics are essential for understanding the electronic properties of perovskite materials.
- 16Chen, T.; Foley, B. J.; Ipek, B.; Tyagi, M.; Copley, J. R. D.; Brown, C. M.; Choi, J. J.; Lee, S.-H. Rotational dynamics of organic cations in the CH3NH3PbI3 perovskite Phys. Chem. Chem. Phys. 2015, 17, 31278– 31286 DOI: 10.1039/C5CP05348JGoogle Scholar16https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhslamsL3M&md5=189c259f9616321de62cf9d18afedd21Rotational dynamics of organic cations in the CH3NH3PbI3 perovskiteChen, Tianran; Foley, Benjamin J.; Ipek, Bahar; Tyagi, Madhusudan; Copley, John R. D.; Brown, Craig M.; Choi, Joshua J.; Lee, Seung-HunPhysical Chemistry Chemical Physics (2015), 17 (46), 31278-31286CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Methylammonium lead iodide (CH3NH3PbI3) based solar cells have shown impressive power conversion efficiencies of above 20%. However, the microscopic mechanism of the high photovoltaic performance is yet to be fully understood. Particularly, the dynamics of CH3NH3+ cations and their impact on relevant processes such as charge recombination and exciton dissocn. are still poorly understood. Here, using elastic and quasi-elastic neutron scattering techniques and group theor. anal., we studied rotational modes of the CH3NH3+ cation in CH3NH3PbI3. Our results show that, in the cubic (T > 327 K) and tetragonal (165 K < T < 327 K) phases, the CH3NH3+ ions exhibit four-fold rotational symmetry of the C-N axis (C4) along with three-fold rotation around the C-N axis (C3), while in the orthorhombic phase (T < 165 K) only C3 rotation is present. At around room temp., the characteristic relaxation times for the C4 rotation are found to be τC4 ≈ 5 ps while for the C3 rotation τC3 ≈ 1 ps. The T-dependent rotational relaxation times were fitted with Arrhenius equations to obtain activation energies. Our data show a close correlation between the C4 rotational mode and the temp. dependent dielec. permittivity. Our findings on the rotational dynamics of CH3NH3+ and the assocd. dipole have important implications for understanding the low exciton binding energy and a slow charge recombination rate in CH3NH3PbI3 which are directly relevant for the high solar cell performance.
- 17Leguy, A. M. A.; Frost, J. M.; McMahon, A. P.; Sakai, V. G.; Kockelmann, W.; Law, C.; Li, X.; Foglia, F.; Walsh, A.; O’Regan, B. C. The dynamics of methylammonium ions in hybrid organic-inorganic perovskite solar cells Nat. Commun. 2015, 6, 7124 DOI: 10.1038/ncomms8124Google Scholar17https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2MfosFGmsQ%253D%253D&md5=31e6a49b8b65b776f79b1c53e28b6e3aThe dynamics of methylammonium ions in hybrid organic-inorganic perovskite solar cellsLeguy Aurelien M A; McMahon Andrew P; Nelson Jenny; Barnes Piers R F; Frost Jarvist Moore; Walsh Aron; Sakai Victoria Garcia; Kochelmann W; Law ChunHung; Li Xiaoe; O'Regan Brian C; Foglia Fabrizia; Cabral Joao TNature communications (2015), 6 (), 7124 ISSN:.Methylammonium lead iodide perovskite can make high-efficiency solar cells, which also show an unexplained photocurrent hysteresis dependent on the device-poling history. Here we report quasielastic neutron scattering measurements showing that dipolar CH3NH3(+) ions reorientate between the faces, corners or edges of the pseudo-cubic lattice cages in CH3NH3PbI3 crystals with a room temperature residence time of ∼14 ps. Free rotation, π-flips and ionic diffusion are ruled out within a 1-200-ps time window. Monte Carlo simulations of interacting CH3NH3(+) dipoles realigning within a 3D lattice suggest that the scattering measurements may be explained by the stabilization of CH3NH3(+) in either antiferroelectric or ferroelectric domains. Collective realignment of CH3NH3(+) to screen a device's built-in potential could reduce photovoltaic performance. However, we estimate the timescale for a domain wall to traverse a typical device to be ∼0.1-1 ms, faster than most observed hysteresis.
- 18Létoublon, A.; Paofai, S.; Rufflé, B.; Bourges, P.; Hehlen, B.; Michel, T.; Ecolivet, C.; Durand, O.; Cordier, S.; Katan, C. Elastic constants, optical phonons, and molecular relaxations in the high temperature plastic phase of the CH3NH3PbBr3 hybrid perovskite J. Phys. Chem. Lett. 2016, 7, 3776– 3784 DOI: 10.1021/acs.jpclett.6b01709Google Scholar18https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsV2gsb7M&md5=bd5c2cf5261f2fc474a3c70833042cc1Elastic Constants, Optical Phonons, and Molecular Relaxations in the High Temperature Plastic Phase of the CH3NH3PbBr3 Hybrid PerovskiteLetoublon, Antoine; Paofai, Serge; Ruffle, Benoit; Bourges, Philippe; Hehlen, Bernard; Michel, Thierry; Ecolivet, Claude; Durand, Olivier; Cordier, Stephane; Katan, Claudine; Even, JackyJournal of Physical Chemistry Letters (2016), 7 (19), 3776-3784CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)Low frequency dynamics was studied in a MeNH3PbBr3 hybrid perovskite single crystal by using 4 different spectroscopy techniques: coherent inelastic neutron, Raman and Brillouin scatterings, and ultrasound measurements. Sound velocities were measured over 5 decades in energy to yield the complete set of elastic consts. in a hybrid halide perovskite crystal in the pseudocubic plastic phase. The C44 shear elastic const. is very small, leading to a particularly low resistance to shear stress. Brillouin scattering was used to study the relaxation dynamics of methylammonium cations and to evidence translation-rotation coupling assocd. with the cubic to tetragonal phase transition at Tc ≈ 230 K. Low frequency and highly damped optical phonons obsd. using both Raman and inelastic neutron <18 meV, do not present softening close to Tc. The crit. dynamics at Tc ≈ 230 K is compatible with an order-disorder character, dominated by relaxational motions of the mols.
- 19Selig, O.; Sadhanala, A.; Müller, C.; Lovrincic, R.; Chen, Z.; Rezus, Y. L. A.; Frost, J. M.; Jansen, T. L. C.; Bakulin, A. A. Organic cation rotation and immobilization in pure and mixed methylammonium lead-halide perovskites J. Am. Chem. Soc. 2017, 139, 4068– 4074 DOI: 10.1021/jacs.6b12239Google Scholar19https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXjsVCmu74%253D&md5=4ae35418cf8381183ff66c1c44965df9Organic Cation Rotation and Immobilization in Pure and Mixed Methylammonium Lead-Halide PerovskitesSelig, Oleg; Sadhanala, Aditya; Mueller, Christian; Lovrincic, Robert; Chen, Zhuoying; Rezus, Yves L. A.; Frost, Jarvist M.; Jansen, Thomas L. C.; Bakulin, Artem A.Journal of the American Chemical Society (2017), 139 (11), 4068-4074CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Three-dimensional lead-halide perovskites have attracted a lot of attention due to their ability to combine soln. processing with outstanding optoelectronic properties. Despite their soft ionic nature these materials demonstrate a surprisingly low level of electronic disorder resulting in sharp band edges and narrow distributions of the electronic energies. Understanding how structural and dynamic disorder impacts the optoelectronic properties of these perovskites is important for many applications. Here the authors combine ultrafast two-dimensional vibrational spectroscopy and mol. dynamics simulations to study the dynamics of the org. methylammonium (MA) cation orientation in a range of pure and mixed trihalide perovskite materials. For pure MAPbX3 (X = I, Br, Cl) perovskite films, the cation dynamics accelerate with decreasing size of the halide atom. This acceleration is surprising given the expected strengthening of the hydrogen bonds between the MA and the smaller halide anions, but can be explained by the increase in the polarizability with the size of halide. Much slower dynamics, up to partial immobilization of the org. cation, are obsd. in the mixed MAPb(ClxBr1-x)3 and MAPb(BrxI1-x)3 alloys, which the authors assoc. with symmetry breaking within the perovskite unit cell. The obsd. dynamics are essential for understanding the effects of structural and dynamical disorder in perovskite-based optoelectronic systems.
- 20Onoda-Yamamuro, N.; Matsuo, T.; Suga, H. Dielectric study of CH3NH3PbX3 (X = Cl, Br, I) J. Phys. Chem. Solids 1992, 53, 935– 939 DOI: 10.1016/0022-3697(92)90121-SGoogle Scholar20https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK38XkvVWnu7k%253D&md5=ffb7e052bff5035c77595ef8e0307414Dielectric study of CH3NH3PbX3 (X = Cl, Br, I)Onoda-Yamamuro, Noriko; Matsuo, Takasuke; Suga, HiroshiJournal of Physics and Chemistry of Solids (1992), 53 (7), 935-9CODEN: JPCSAW; ISSN:0022-3697.Complex dielec. permittivities of CH3NH3PbX3 (X = Cl, Br, I) were measured at frequencies between 20 Hz and 1 MHz and at 20-300 K (15-350 K for the iodide). Discontinuities or a sharp bend of the real part of the dielec. permittivity occurred at the phase transitions, except at the tetragonal (I4/mcm)-cubic phase transition where the permittivity showed no apparent change. The dielec. behaviors in the cubic and tetragonal (I4/mcm) phases are described well by a modified Kirkwood-Froehlich equation. Dielec. dispersions were found in the orthorhombic phase of CH3NH3PbBr3 and CH3NH3PbI3 at 30-120 K.
- 21Quarti, C.; Grancini, G.; Mosconi, E.; Bruno, P.; Ball, J. M.; Lee, M. M.; Snaith, H. J.; Petrozza, A.; Angelis, F. D. The Raman spectrum of the CH3NH3PbI3 hybrid perovskite: interplay of theory and experiment J. Phys. Chem. Lett. 2014, 5, 279– 284 DOI: 10.1021/jz402589qGoogle Scholar21https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhvFyrtr7P&md5=dca655cda936ae4e6fddcb2e4ce862e5The Raman Spectrum of the CH3NH3PbI3 Hybrid Perovskite: Interplay of Theory and ExperimentQuarti, Claudio; Grancini, Giulia; Mosconi, Edoardo; Bruno, Paola; Ball, James M.; Lee, Michael M.; Snaith, Henry J.; Petrozza, Annamaria; Angelis, Filippo DeJournal of Physical Chemistry Letters (2014), 5 (2), 279-284CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)The authors report the low-frequency resonant Raman spectrum of methylammonium Pb-iodide, a prototypical perovskite for solar cells applications, on mesoporous Al2O3. The measured spectrum assignment is assisted by DFT simulations of the Raman spectra of suitable periodic and model systems. The bands at 62 and 94 cm-1 are assigned resp. to the bending and to the stretching of the Pb-I bonds, and are thus diagnostic modes of the inorg. cage. The authors also assign the librations of the org. cations at 119 and 154 cm-1. The broad, unstructured 200-400 cm-1 features are assigned to the torsional mode of the methylammonium cations, which the authors propose as a marker of the orientational disorder of the material. Study provides the basis to interpret the Raman spectra of organohalide perovskites, which may allow 1 to further understand the properties of this important class of materials in relation to their full exploitation in solar cells.
- 22Brivio, F.; Frost, J. M.; Skelton, J. M.; Jackson, A. J.; Weber, O. J.; Weller, M. T.; Goñi, A. R.; Leguy, A. M. A.; Barnes, P. R. F.; Walsh, A. Lattice dynamics and vibrational spectra of the orthorhombic, tetragonal, and cubic phases of methylammonium lead iodide Phys. Rev. B: Condens. Matter Mater. Phys. 2015, 92, 144308 DOI: 10.1103/PhysRevB.92.144308Google Scholar22https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XktlOruro%253D&md5=d032de453e4ee67d539fe3c2501b99d8Lattice dynamics and vibrational spectra of the orthorhombic, tetragonal, and cubic phases of methylammonium lead iodideBrivio, Federico; Frost, Jarvist M.; Skelton, Jonathan M.; Jackson, Adam J.; Weber, Oliver J.; Weller, Mark T.; Goni, Alejandro R.; Leguy, Aurelien M. A.; Barnes, Piers R. F.; Walsh, AronPhysical Review B: Condensed Matter and Materials Physics (2015), 92 (14), 144308/1-144308/8CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The hybrid halide perovskite CH3NH3PbI3 exhibits a complex structural behavior, with successive transitions between orthorhombic, tetragonal, and cubic polymorphs around 165 and 327 K. Herein we report first-principles lattice dynamics (phonon spectrum) for each phase of CH3NH3PbI3. The equil. structures compare well to solns. of temp.-dependent powder neutron diffraction. By following the normal modes, we calc. IR and Raman intensities of the vibrations, and compare them to the measurement of a single crystal where the Raman laser is controlled to avoid degrdn. of the sample. Despite a clear sepn. in energy between low-frequency modes assocd. with the inorg. (PbI3-)n network and high-frequency modes of the org. CH3NH3+ cation, significant coupling between them is found, which emphasizes the interplay between mol. orientation and the corner-sharing octahedral networks in the structural transformations. Soft modes are found at the boundary of the Brillouin zone of the cubic phase, consistent with displacive instabilities and anharmonicity involving tilting of the PbI6 octahedra around room temp.
- 23Stoumpos, C. C.; Malliakas, C. D.; Kanatzidis, M. G. Semiconducting tin and lead iodide perovskites with organic cations: phase transitions, high mobilities, and near-infrared photoluminescent properties Inorg. Chem. 2013, 52, 9019– 9038 DOI: 10.1021/ic401215xGoogle Scholar23https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtVGqsL3N&md5=94c35d645dcd9770b4097d0bd440269bSemiconducting Tin and Lead Iodide Perovskites with Organic Cations: Phase Transitions, High Mobilities, and Near-Infrared Photoluminescent PropertiesStoumpos, Constantinos C.; Malliakas, Christos D.; Kanatzidis, Mercouri G.Inorganic Chemistry (2013), 52 (15), 9019-9038CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)A broad org.-inorg. series of hybrid metal iodide perovskites AMI3, where A is the methylammonium (MeNH3+) or formamidinium (HC(NH2)2+) cation and M is Sn (1 and 2) or Pb (3 and 4) are reported. The compds. were prepd. through a variety of synthetic approaches, and the nature of the resulting materials is discussed in terms of their thermal stability and optical and electronic properties. The chem. and phys. properties of these materials strongly depend on the prepn. method. Single crystal x-ray diffraction anal. of 1-4 classifies the compds. in the perovskite structural family. Structural phase transitions were obsd. and studied by temp.-dependent single crystal x-ray diffraction in the 100-400 K range. The charge transport properties of the materials are discussed in conjunction with diffuse reflectance studies in the mid-IR region that display characteristic absorption features. Temp.-dependent studies show a strong dependence of the resistivity as a function of the crystal structure. Optical absorption measurements indicate that 1-4 behave as direct-gap semiconductors with energy band gaps distributed at 1.25-1.75 eV. The compds. exhibit an intense near-IR luminescence (PL) emission in the 700-1000 nm range (1.1-1.7 eV) at room temp. Solid solns. between the Sn and Pb compds. are readily accessible throughout the compn. range. The optical properties such as energy band gap, emission intensity, and wavelength can be readily controlled for the isostructural series of solid solns. MeNH3Sn1-xPbxI3 (5). The charge transport type in these materials was characterized by Seebeck coeff. and Hall-effect measurements. The compds. behave as p- or n-type semiconductors depending on the prepn. method. The samples with the lowest carrier concn. are prepd. from soln. and are n-type; p-type samples can be obtained through solid state reactions exposed in air in a controllable manner. In the case of Sn compds., there is a facile tendency toward oxidn. which causes the materials to be doped with Sn4+ and thus behave as p-type semiconductors displaying metal-like cond. The compds. appear to possess very high estd. electron and hole mobilities that exceed 2000 cm2/(V s) and 300 cm2/(V s), resp., as shown in the case of MeNH3SnI3 (1). The authors also compare the properties of the title hybrid materials with those of the all-inorg. CsSnI3 and CsPbI3 prepd. using identical synthetic methods.
- 24Frost, J. M.; Butler, K. T.; Brivio, F.; Hendon, C. H.; van Schilfgaarde, M.; Walsh, A. Atomistic origins of high-performance in hybrid halide perovskite solar cells Nano Lett. 2014, 14, 2584– 2590 DOI: 10.1021/nl500390fGoogle Scholar24https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXltF2nu7Y%253D&md5=3b52f943bd4e397862fd02953c1e11faAtomistic Origins of High-Performance in Hybrid Halide Perovskite Solar CellsFrost, Jarvist M.; Butler, Keith T.; Brivio, Federico; Hendon, Christopher H.; van Schilfgaarde, Mark; Walsh, AronNano Letters (2014), 14 (5), 2584-2590CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)The performance of organometallic perovskite solar cells has rapidly surpassed that of both conventional dye-sensitized and org. photovoltaics. High-power conversion efficiency can be realized in both mesoporous and thin-film device architectures. The authors address the origin of this success in the context of the materials chem. and physics of the bulk perovskite as described by electronic structure calcns. In addn. to the basic optoelectronic properties essential for an efficient photovoltaic device (spectrally suitable band gap, high optical absorption, low carrier effective masses), the materials are structurally and compositionally flexible. As the authors show, hybrid perovskites exhibit spontaneous elec. polarization; the authors also suggest ways in which this can be tuned through judicious choice of the org. cation. The presence of ferroelec. domains will result in internal junctions that may aid sepn. of photoexcited electron and hole pairs, and redn. of recombination through segregation of charge carriers. The combination of high dielec. const. and low effective mass promotes both Wannier-Mott exciton sepn. and effective ionization of donor and acceptor defects. The photoferroic effect could be exploited in nanostructured films to generate a higher open circuit voltage and may contribute to the current-voltage hysteresis obsd. in perovskite solar cells.
- 25Kutes, Y.; Ye, L.; Zhou, Y.; Pang, S.; Huey, B. D.; Padture, N. P. Direct observation of ferroelectric domains in solution-processed CH3NH3PbI3 perovskite thin films J. Phys. Chem. Lett. 2014, 5, 3335– 3339 DOI: 10.1021/jz501697bGoogle Scholar25https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsFCjsbrO&md5=88f2a0705f393c936074acd540b2f34bDirect Observation of Ferroelectric Domains in Solution-Processed CH3NH3PbI3 Perovskite Thin FilmsKutes, Yasemin; Ye, Linghan; Zhou, Yuanyuan; Pang, Shuping; Huey, Bryan D.; Padture, Nitin P.Journal of Physical Chemistry Letters (2014), 5 (19), 3335-3339CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)A new generation of solid-state photovoltaics is being made possible by the use of organometal-trihalide perovskite materials. While some of these materials are expected to be ferroelec., almost nothing is known about their ferroelec. properties exptl. Using piezoforce microscopy (PFM), here we show unambiguously, for the first time, the presence of ferroelec. domains in high-quality β-CH3NH3PbI3 perovskite thin films that have been synthesized using a new soln.-processing method. The size of the ferroelec. domains is found to be about the size of the grains (∼100 nm). We also present evidence for the reversible switching of the ferroelec. domains by poling with DC biases. This suggests the importance of further PFM investigations into the local ferroelec. behavior of hybrid perovskites, in particular in situ photoeffects. Such investigations could contribute toward the basic understanding of photovoltaic mechanisms in perovskite-based solar cells, which is essential for the further enhancement of the performance of these promising photovoltaics.
- 26Wei, J.; Zhao, Y.; Li, H.; Li, G.; Pan, J.; Xu, D.; Zhao, Q.; Yu, D. Hysteresis analysis based on the ferroelectric effect in hybrid perovskite solar cells J. Phys. Chem. Lett. 2014, 5, 3937– 3945 DOI: 10.1021/jz502111uGoogle Scholar26https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvVWgu7zL&md5=4ea652347f2a38bbe75e25dde860542cHysteresis Analysis Based on the Ferroelectric Effect in Hybrid Perovskite Solar CellsWei, Jing; Zhao, Yicheng; Li, Heng; Li, Guobao; Pan, Jinlong; Xu, Dongsheng; Zhao, Qing; Yu, DapengJournal of Physical Chemistry Letters (2014), 5 (21), 3937-3945CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)The power conversion efficiency (PCE) of CH3NH3PbX3 (X = I, Br, Cl) perovskite solar cells was developed rapidly from 6.5 to 18% within 3 years. However, the anomalous hysteresis found in I-V measurements can cause an inaccurate estn. of the efficiency. The authors attribute the phenomena to the ferroelec. effect and build a model based on the ferroelec. diode to explain it. The ferroelec. effect of CH3NH3PbI3-xClx is strongly suggested by characterization methods and the E-P (elec. field-polarization) loop. The hysteresis in I-V curves greatly depends on the scan range as well as the velocity, which is well explained by the ferroelec. diode model. Also the current signals show exponential decay in ∼10 s under prolonged stepwise measurements, and the anomalous hysteresis disappears using these stabilized current values. The exptl. results accord well with the model based on ferroelec. properties and prove that prolonged stepwise measurement is an effective way to evaluate the real efficiency of perovskite solar cells. Most importantly, this work provides a meaningful perspective that the ferroelec. effect (if it really exists) should be paid special attention in the optimization of perovskite solar cells.
- 27Quarti, C.; Mosconi, E.; De Angelis, F. Interplay of orientational order and electronic structure in methylammonium lead iodide: implications for solar cell operation Chem. Mater. 2014, 26, 6557– 6569 DOI: 10.1021/cm5032046Google Scholar27https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsl2ht77E&md5=fbfd6eb91c91e82068bdb7213ba8cc86Interplay of Orientational Order and Electronic Structure in Methylammonium Lead Iodide: Implications for Solar CellQuarti, Claudio; Mosconi, Edoardo; De Angelis, FilippoChemistry of Materials (2014), 26 (22), 6557-6569CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)The ab initio electronic structure and Car-Parrinello mol. dynamics simulations are reported for several structural models of the prototype MAPbI3 perovskite for solar cells applications. Both configurations having a preferred orientation are considered of the MA cations, giving rise to a net dipole alignment, and configurations with an isotropic distribution of the MA cations, resp. representative of polar (ferroelec.) and apolar (antiferroelec.) structures. The calcns. demonstrate the preferred stability of a set of polar structures over apolar ones, with an energy difference within 0.1 eV and a conversion barrier within 0.2 eV per unit cell (four MAPbI3), thus possibly accessible at room temp. Ferroelec.-like orientations lead to a quasi I4cm structure for the inorg. component, characterized by lack of inversion symmetry, while the antiferroelec.-like orientations are assocd. to a quasi I4/mcm structure. Ab initio mol. dynamics simulations on the polar structures show no mol. rotations in the investigated time-scale, while several MA rotations are obsd. in the same time scale for the considered apolar structure, which is thus characterized by a higher disorder. The I4cm and I4/mcm types of structure have markedly different band structures, despite showing a relatively small band gap variation. Simulations carried out on finite surface slabs demonstrate that a net orientation of the MA cations gives rise to a strong bending in the valence and conduction bands, which could definitely assist charge sepn. and reduce carrier recombination, provided one is able to effectively stabilize polar compared to apolar structures. The results could contribute an important step toward an in-depth comprehension of the basic properties of organohalide perovskites, assisting a further optimization of their photovoltaic response.
- 28Chen, H.-W.; Sakai, N.; Ikegami, M.; Miyasaka, T. Emergence of hysteresis and transient ferroelectric response in organo-lead halide perovskite solar cells J. Phys. Chem. Lett. 2015, 6, 164– 169 DOI: 10.1021/jz502429uGoogle Scholar28https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXitFehsL3K&md5=2d086a807969d24950871b8ea2f3262aEmergence of Hysteresis and Transient Ferroelectric Response in Organo-Lead Halide Perovskite Solar CellsChen, Hsin-Wei; Sakai, Nobuya; Ikegami, Masashi; Miyasaka, TsutomuJournal of Physical Chemistry Letters (2015), 6 (1), 164-169CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)Although there was rapid progress in the efficiency of perovskite-based solar cells, hysteresis in the current-voltage performance is not yet completely understood. Owing to its complex structure, it is not easy to attribute the hysteretic behavior to any one of different components, such as the bulk of the perovskite or different heterojunction interfaces. Among organo-lead halide perovskites, methylammonium lead iodide perovskite (CH3NH3PbI3) is known to have a ferroelec. property. The present study reveals a strong correlation between transient ferroelec. polarization of CH3NH3PbI3 induced by an external bias in the dark and hysteresis enhancement in photovoltaic characteristics. The authors' results demonstrate that the reverse bias poling (-0.3 to -1.1 V) of CH3NH3PbI3 photovoltaic layers prior to the photocurrent-voltage measurement generates stronger hysteresis whose extent changes significantly by the cell architecture. The phenomenon is interpreted as the effect of remanent polarization in the perovskite film on the photocurrent, which is most enhanced in planar perovskite structures without mesoporous scaffolds.
- 29Zheng, F.; Takenaka, H.; Wang, F.; Koocher, N. Z.; Rappe, A. M. First-principles calculation of the bulk photovoltaic effect in CH3NH3PbI3 and CH3NH3PbI3–xClx J. Phys. Chem. Lett. 2015, 6, 31– 37 DOI: 10.1021/jz502109eGoogle Scholar29https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvFOhtr7E&md5=45844907636fe1a492ccc168915d0193First-Principles Calculation of the Bulk Photovoltaic Effect in CH3NH3PbI3 and CH3NH3PbI3-xClxZheng, Fan; Takenaka, Hiroyuki; Wang, Fenggong; Koocher, Nathan Z.; Rappe, Andrew M.Journal of Physical Chemistry Letters (2015), 6 (1), 31-37CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)Hybrid halide perovskites exhibit nearly 20% power conversion efficiency, but the origin of their high efficiency is still unknown. Here, we compute the shift current, a dominant mechanism of the bulk photovoltaic (PV) effect for ferroelec. photovoltaics, in CH3NH3PbI3 and CH3NH3PbI3-xClx from first-principles. We find that these materials give approx. three times larger shift current PV response to near-IR and visible light than the prototypical ferroelec. photovoltaic BiFeO3. The mol. orientations of CH3NH+3 can strongly affect the corresponding PbI3 inorg. frame so as to alter the magnitude of the shift current response. Specifically, configurations with dipole moments aligned in parallel distort the inorg. PbI3 frame more significantly than configurations with near-net-zero dipole, yielding a larger shift current response. Furthermore, we explore the effect of Cl substitution on shift current and find that Cl substitution at the equatorial site induces a larger response than does substitution at the apical site.
- 30Chen, B.; Shi, J.; Zheng, X.; Zhou, Y.; Zhu, K.; Priya, S. Ferroelectric solar cells based on inorganic-organic hybrid perovskites J. Mater. Chem. A 2015, 3, 7699– 7705 DOI: 10.1039/C5TA01325AGoogle Scholar30https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXjvF2ktLs%253D&md5=be7d1c8eac955bb64b4e1bb5f249e438Ferroelectric solar cells based on inorganic-organic hybrid perovskitesChen, Bo; Shi, Jian; Zheng, Xiaojia; Zhou, Yuan; Zhu, Kai; Priya, ShashankJournal of Materials Chemistry A: Materials for Energy and Sustainability (2015), 3 (15), 7699-7705CODEN: JMCAET; ISSN:2050-7496. (Royal Society of Chemistry)Ferroelec. solar cells based on ferroelec. oxides have attracted significant attention owing to many unique advantages, such as the switchable photocurrent and photovoltage, and the above bandgap open circuit voltages. However, the small photocurrent densities of the typical ferroelec. solar cells greatly limit their photovoltaic performance. In this report, the polarization switching properties of inorg.-org. hybrid perovskites are revealed exptl. and ferroelec. solar cells based on the hybrid perovskites are developed. Hybrid perovskite methylammonium lead trihalide (MAPbX3) thin films exhibited 180° domain phase switching and polarization hysteresis loops. Ferroelec. solar cells based on the mixed halide MAPbI3-xClx thin film demonstrate a power conversion efficiency of 6.7% and the ferroelec. solar cells display switchable photovoltaic effects. This work provides an alternative but exhilarating soln. for high-performance ferroelec. solar cells beyond inorg. ferroelec. oxides.
- 31Dang, Y.; Liu, Y.; Sun, Y.; Yuan, D.; Liu, X.; Lu, W.; Liu, G.; Xia, H.; Tao, X. Bulk crystal growth of hybrid perovskite material CH3NH3PbI3 CrystEngComm 2015, 17, 665– 670 DOI: 10.1039/C4CE02106AGoogle Scholar31https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXitVSit7zO&md5=25b523421d793fb45e82b8d424e10929Bulk crystal growth of hybrid perovskite material CH3NH3PbI3Dang, Yangyang; Liu, Yang; Sun, Youxuan; Yuan, Dongsheng; Liu, Xiaolong; Lu, Weiqun; Liu, Guangfeng; Xia, Haibing; Tao, XutangCrystEngComm (2015), 17 (3), 665-670CODEN: CRECF4; ISSN:1466-8033. (Royal Society of Chemistry)Org.-inorg. hybrid perovskite materials have been receiving considerable attention due to their promising applications in many optoelectronic fields. However, some of the fundamental properties of perovskite materials are still disputed, because most of them are derived from a thin-film state. To comprehend the intrinsic characteristics in a single crystal, herein we report, for the first time, the bulk crystal growth of CH3NH3PbI3. Single crystals of tetragonal CH3NH3PbI3 with dimensions of 10 mm × 10 mm × 8 mm were grown by a temp.-lowering method in HI soln. Studies in to the refinement and orientations of the CH3NH3PbI3 single crystal structure were conducted based on a high quality crystal. The absorption edge of a CH3NH3PbI3 single crystal was located at about 836 nm, indicating that the band gap of CH3NH3PbI3 is approx. 1.48 eV, which is close to the theor. results and smaller than those derived from polycryst. and thin-films. CH3NH3PbI3 crystal exhibits a relatively wide absorption (from 250 nm to 800 nm) and a relatively good thermal stability.
- 32Kim, H.-S.; Kim, S. K.; Kim, B. J.; Shin, K.-S.; Gupta, M. K.; Jung, H. S.; Kim, S.-W.; Park, N.-G. Ferroelectric polarization in CH3NH3PbI3 perovskite J. Phys. Chem. Lett. 2015, 6, 1729– 1735 DOI: 10.1021/acs.jpclett.5b00695Google Scholar32https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXmvVynuro%253D&md5=34bd8f150addf70e3a27a2a2859e9647Ferroelectric Polarization in CH3NH3PbI3 PerovskiteKim, Hui-Seon; Kim, Sung Kyun; Kim, Byeong Jo; Shin, Kyung-Sik; Gupta, Manoj Kumar; Jung, Hyun Suk; Kim, Sang-Woo; Park, Nam-GyuJournal of Physical Chemistry Letters (2015), 6 (9), 1729-1735CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)We report on ferroelec. polarization behavior in CH3NH3PbI3 perovskite in the dark and under illumination. Perovskite crystals with three different sizes of 700, 400, and 100 nm were prepd. for piezoresponse force microscopy (PFM) measurements. PFM results confirmed the formation of spontaneous polarization in CH3NH3PbI3 in the absence of elec. field, where the size dependency to polarization was not significant. Whereas the photoinduced stimulation was not significant without an external elec. field, the stimulated polarization by poling was further enhanced under illumination. The retention of ferroelec. polarization was also obsd. after removal of the elec. field, in which larger crystals showed longer retention behavior compared to the smaller sized one. Addnl., we suggest the effect of perovskite crystal size (morphol.) on charge collection at the interface of the ferroelec. material even though insignificant size dependency in elec. polarization was obsd.
- 33Liu, S.; Zheng, F.; Koocher, N. Z.; Takenaka, H.; Wang, F.; Rappe, A. M. Ferroelectric domain wall induced band gap reduction and charge separation in organometal halide perovskites J. Phys. Chem. Lett. 2015, 6, 693– 699 DOI: 10.1021/jz502666jGoogle Scholar33https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtlyqsrc%253D&md5=67a184d53926d79ffbafd47f7b416686Ferroelectric domain wall induced band gap reduction and charge separation in organometal halide perovskitesLiu, Shi; Zheng, Fan; Koocher, Nathan Z.; Takenaka, Hiroyuki; Wang, Fenggong; Rappe, Andrew M.Journal of Physical Chemistry Letters (2015), 6 (4), 693-699CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)Organometal halide perovskites have been intensely studied in the past 5 years, inspired by their certified high photovoltaic power conversion efficiency. Some of these materials are room-temp. ferroelecs. The presence of switchable ferroelec. domains in methylammonium lead triiodide, CH3NH3PbI3, has recently been obsd. via piezoresponse force microscopy. Here, we focus on the structural and electronic properties of ferroelec. domain walls in CH3NH3PbX3 (X = Cl, Br, I). We find that organometal halide perovskites can form both charged and uncharged domain walls due to the flexible orientational order of the org. mols. The electronic band gaps for domain structures possessing 180 and 90° walls are estd. with d. functional theory. It is found that the presence of charged domain walls will significantly reduce the band gap by 20-40%, while the presence of uncharged domain walls has no substantial impact on the band gap. We demonstrate that charged domain walls can serve as segregated channels for the motions of charge carriers. These results highlight the importance of ferroelec. domain walls in hybrid perovskites for photovoltaic applications and suggest a possible avenue for device optimization through domain patterning.
- 34Rashkeev, S. N.; El-Mellouhi, F.; Kais, S.; Alharbi, F. H. Domain walls conductivity in hybrid organometallic perovskites and their essential role in CH3NH3PbI3 solar cell high performance Sci. Rep. 2015, 5, 11467 DOI: 10.1038/srep11467Google Scholar34https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtFyhsbnP&md5=97d09bc93586801654e60ebff355ec33Domain Walls Conductivity in Hybrid Organometallic Perovskites and Their Essential Role in CH3NH3PbI3 Solar Cell High PerformanceRashkeev, Sergey N.; El-Mellouhi, Fedwa; Kais, Sabre; Alharbi, Fahhad H.Scientific Reports (2015), 5 (), 11467CODEN: SRCEC3; ISSN:2045-2322. (Nature Publishing Group)The past several years has witnessed a surge of interest in organometallic trihalide perovskites, which are at the heart of the new generation of solid-state solar cells. Here, we calcd. the static cond. of charged domain walls in n- and p- doped organometallic uniaxial ferroelec. semiconductor perovskite CH3NH3PbI3 using the Landau-Ginzburg-Devonshire (LGD) theory. We find that due to the charge carrier accumulation, the static cond. may drastically increase at the domain wall by 3 - 4 orders of magnitude in comparison with cond. through the bulk of the material. Also, a two-dimensional degenerated gas of highly mobile charge carriers could be formed at the wall. The high values of cond. at domain walls and interfaces explain high efficiency in organometallic soln.-processed perovskite films which contains lots of different point and extended defects. These results could suggest new routes to enhance the performance of this promising class of novel photovoltaic materials.
- 35Stroppa, A.; Quarti, C.; De Angelis, F.; Picozzi, S. Ferroelectric polarization of CH3NH3PbI3: a detailed study based on density functional theory and symmetry mode analysis J. Phys. Chem. Lett. 2015, 6, 2223– 2231 DOI: 10.1021/acs.jpclett.5b00542Google Scholar35https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXovFKqtLY%253D&md5=be712c52c0a6929b5374bf318651d59cFerroelectric Polarization of CH3NH3PbI3: A Detailed Study Based on Density Functional Theory and Symmetry Mode AnalysisStroppa, Alessandro; Quarti, Claudio; De Angelis, Filippo; Picozzi, SilviaJournal of Physical Chemistry Letters (2015), 6 (12), 2223-2231CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)Ferroelectricity in halide perovskites currently represents a crucial issue, as it may have an important role for the enhancement of solar cells efficiency. Simulations of ferroelec. properties based on d. functional theory are conceptually more demanding compared with conventional inorg. ferroelecs. due to the presence of both org. and inorg. components in the same compd. Here the authors present a detailed study focused on the prototypical CH3NH3PbI3 perovskite. By using d. functional theory combined with symmetry mode anal., the authors disentangle the contributions of the methylammonium cations and the role of the inorg. framework, therefore suggesting possible routes to enhance the polarization in this compd. The authors' est. of the polarization for the tetragonal phase at low temp. is ∼4.42 μC/cm2, which is substantially lower than that of traditional perovskite oxides.
- 36Seol, D.; Han, G. S.; Bae, C.; Shin, H.; Jung, H. S.; Kim, Y. Screening effect on photovoltaic performance in ferroelectric CH3NH3PbI3 perovskite thin films J. Mater. Chem. A 2015, 3, 20352– 20358 DOI: 10.1039/C5TA06190CGoogle Scholar36https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsVegsbbO&md5=7075589378b89e823bb0afe24e64338bScreening effect on photovoltaic performance in ferroelectric CH3NH3PbI3 perovskite thin filmsSeol, Daehee; Han, Gill Sang; Bae, Changdeuck; Shin, Hyunjung; Jung, Hyun Suk; Kim, YunseokJournal of Materials Chemistry A: Materials for Energy and Sustainability (2015), 3 (40), 20352-20358CODEN: JMCAET; ISSN:2050-7496. (Royal Society of Chemistry)Org. and inorg. hybrid materials of CH3NH3PbX3 with a perovskite crystal structure have been conceived as emerging light absorbing materials for high efficiency photovoltaic devices. Here, we demonstrate the screening effect of polarization states on charge redistribution related to the photovoltaic performance of ferroelec. CH3NH3PbI3 thin films using at. force microscopy. We show the interplay between polarization and injected charges to have significant effects on charge transfer which potentially influences photovoltaic performance. The obtained results reveal that the direction and the amt. of charge transfer can be influenced by the screening of polarization states at the interface. These results could deliver fundamental information regarding the influence of ferroelectricity on CH3NH3PbX3 solar cells.
- 37Zhao, P.; Xu, J.; Ma, C.; Ren, W.; Wang, L.; Bian, L.; Chang, A. Spontaneous polarization behaviors in hybrid halide perovskite film Scr. Mater. 2015, 102, 51– 54 DOI: 10.1016/j.scriptamat.2015.01.030Google Scholar37https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXjvFCis7s%253D&md5=6441cb0eb746d824ff843b3d07e2e9caSpontaneous polarization behaviors in hybrid halide perovskite filmZhao, Pengjun; Xu, Jinbao; Ma, Chao; Ren, Wei; Wang, Lei; Bian, Liang; Chang, AiminScripta Materialia (2015), 102 (), 51-54CODEN: SCMAF7; ISSN:1359-6462. (Elsevier Ltd.)Spontaneous polarization behaviors of hybrid perovskite CH3NH3PbI3 film were confirmed by in situ PFM and spectroscopic ellipsometry. The film exhibits uniform spontaneous polarization and ferroelec. domain inversion performance. The fitted dielec. consts. spectra agree well with the calcd. ones. We attribute the spontaneous polarization behaviors of hybrid perovskite to lone pair electrons, and its outstanding photovoltaic performance partially originates from spontaneous polarization and plasma resonance. This report will facilitate understanding of the instinct phys. essence of hybrid perovskite solar cells.
- 38Hermes, I. M.; Bretschneider, S. A.; Bergmann, V. W.; Li, D.; Klasen, A.; Mars, J.; Tremel, W.; Laquai, F.; Butt, H.-J.; Mezger, M. Ferroelastic fingerprints in methylammonium lead iodide perovskite J. Phys. Chem. C 2016, 120, 5724– 5731 DOI: 10.1021/acs.jpcc.5b11469Google Scholar38https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XisVyhtL4%253D&md5=c975b568cd875558162b5ce24baaf007Ferroelastic Fingerprints in Methylammonium Lead Iodide PerovskiteHermes, Ilka M.; Bretschneider, Simon A.; Bergmann, Victor W.; Li, Dan; Klasen, Alexander; Mars, Julian; Tremel, Wolfgang; Laquai, Frederic; Butt, Hans-Juergen; Mezger, Markus; Berger, Ruediger; Rodriguez, Brian J.; Weber, Stefan A. L.Journal of Physical Chemistry C (2016), 120 (10), 5724-5731CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Methylammonium lead iodide (MAPbI3) perovskite shows an outstanding performance in photovoltaic devices. However, certain material properties, esp. the possible ferroic behavior, remain unclear. We obsd. distinct nanoscale periodic domains in the piezoresponse of MAPbI3(Cl) grains. The structure and the orientation of these striped domains indicate ferroelasticity as their origin. By correlating vertical and lateral piezoresponse force microscopy expts. performed at different sample orientations with X-ray diffraction, the preferred domain orientation is suggested to be the a1-a2-phase. The observation of these ferroelastic fingerprints appears to strongly depend on the film texture and thus the prepn. route. The ferroelastic twin domains could form due to the introduction of strain during the cubic-tetragonal phase transition.
- 39Wang, P.; Zhao, J.; Wei, L.; Zhu, Q.; Xie, S.; Liu, J.; Meng, X.; Li, J. Photo-induced ferroelectric switching in perovskite CH3NH3PbI3 films Nanoscale 2017, 9, 3806– 3817 DOI: 10.1039/C6NR09310HGoogle Scholar39https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhs1KisL0%253D&md5=9cd141c5886e632a4573e4158725d322Photo-induced ferroelectric switching in perovskite CH3NH3PbI3 filmsWang, Peiqi; Zhao, Jinjin; Wei, Liyu; Zhu, Qingfeng; Xie, Shuhong; Liu, Jinxi; Meng, Xiangjian; Li, JiangyuNanoscale (2017), 9 (11), 3806-3817CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)The photovoltaic conversion efficiency of perovskite solar cells based on org.-inorg. CH3NH3PbI3 has risen spectacularly from 3.8% to over 20% in just seven years, yet quite a few important fundamental issues have not been settled, and the role of spontaneous polarization remains poorly understood. While piezoresponse force microscopy (PFM) has been adopted to probe possible ferroelectricity in CH3NH3PbI3, the reported data are often conflicting and inconclusive, due to the complexity in the apparent piezoresponse and its switching that may arise from ionic motions, electrostatic interactions, and other electromech. mechanisms. Here, using a combination of microscopic and macroscopic measurements, we unambiguously establish the linear piezoelectricity of CH3NH3PbI3 arising from its spontaneous polarization, which can be switched by an elec. field, though other electromech. contributions such as ionic motions are also shown to exist. More importantly, we demonstrate strong interactions between polarization and light in technol. relevant CH3NH3PbI3 films with good conversion efficiencies, observing that the spontaneous polarization can also be switched by light illumination in the absence of an elec. field. The light is shown to reduce the coercive voltage of CH3NH3PbI3 and shifts its nucleation bias, suggesting that the photo-induced switching is caused by ionic motions in combination with a photovoltaic field. This set of studies offer strong evidence on the interactions among photo-induced charges, polarization, and ions in perovskite CH3NH3PbI3, and these fundamental observations lay the ground for answering the technol. important question regarding the effects of ferroelectricity on its photovoltaic conversion.
- 40Rakita, Y.; Bar-Elli, O.; Meirzadeh, E.; Kaslasi, H.; Peleg, Y.; Hodes, G.; Lubomirsky, I.; Oron, D.; Ehre, D.; Cahen, D. Tetragonal CH3NH3PbI3 is ferroelectric Proc. Natl. Acad. Sci. U. S. A. 2017, 114, E5504– E5512 DOI: 10.1073/pnas.1702429114Google Scholar40https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXptlSguro%253D&md5=b90071fbf65dbdd83662816c525234fbTetragonal CH3NH3PbI3 is ferroelectricRakita, Yevgeny; Bar-Elli, Omri; Meirzadeh, Elena; Kaslasi, Hadar; Peleg, Yagel; Hodes, Gary; Lubomirsky, Igor; Oron, Dan; Ehre, David; Cahen, DavidProceedings of the National Academy of Sciences of the United States of America (2017), 114 (28), E5504-E5512CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)Halide perovskite (HaP) semiconductors are revolutionizing photovoltaic (PV) solar energy conversion by showing remarkable performance of solar cells made with HaPs, esp. tetragonal methylammonium lead triiodide (MAPbI3). In particular, the low voltage loss of these cells implies a remarkably low recombination rate of photogenerated carriers. It was suggested that low recombination can be due to the spatial sepn. of electrons and holes, a possibility if MAPbI3 is a semiconducting ferroelec., which, however, requires clear exptl. evidence. As a first step, we show that, in operando, MAPbI3 (unlike MAPbBr3) is pyroelec., which implies it can be ferroelec. The next step, proving it is (not) ferroelec., is challenging, because of the material's relatively high elec. conductance (a consequence of an optical band gap suitable for PV conversion) and low stability under high applied bias voltage. This excludes normal measurements of a ferroelec. hysteresis loop, to prove ferroelectricity's hallmark switchable polarization. By adopting an approach suitable for elec. leaky materials as MAPbI3, we show here ferroelec. hysteresis from well-characterized single crystals at low temp. (still within the tetragonal phase, which is stable at room temp.). By chem. etching, we also can image the structural fingerprint for ferroelectricity, polar domains, periodically stacked along the polar axis of the crystal, which, as predicted by theory, scale with the overall crystal size. We also succeeded in detecting clear second harmonic generation, direct evidence for the material's noncentrosymmetry. We note that the material's ferroelec. nature, can, but need not be important in a PV cell at room temp.
- 41Rohm, H.; Leonhard, T.; Hoffmann, M. J.; Colsmann, A. Ferroelectric domains in methylammonium lead iodide perovskite thin-films Energy Environ. Sci. 2017, 10, 950– 955 DOI: 10.1039/C7EE00420FGoogle ScholarThere is no corresponding record for this reference.
- 42Mosconi, E.; Quarti, C.; Ivanovska, T.; Ruani, G.; De Angelis, F. Structural and electronic properties of organo-halide lead perovskites: a combined IR-spectroscopy and ab initio molecular dynamics investigation Phys. Chem. Chem. Phys. 2014, 16, 16137– 16144 DOI: 10.1039/C4CP00569DGoogle Scholar42https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtVGgsbzF&md5=64bb435e1189cfb224043cfbe245f7c4Structural and electronic properties of organo-halide lead perovskites: a combined IR-spectroscopy and ab initio molecular dynamics investigationMosconi, Edoardo; Quarti, Claudio; Ivanovska, Tanja; Ruani, Giampiero; De Angelis, FilippoPhysical Chemistry Chemical Physics (2014), 16 (30), 16137-16144CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Organo-halide lead perovskites are revolutionizing the photovoltaic scenario, with efficiencies exceeding 15%. The orientational dynamics disorder of the methylammonium cations (MA) is one of the most peculiar features of these materials. Here, the authors perform ab initio mol. dynamics simulations and IR spectroscopic measurements on lead halide hybrid perovskites to elucidate the rotational motion of the MA cations in these systems and its effects on the structural and electronic properties of hybrid perovskites. In the studied time frame, the MA cations rotate within the inorg. framework on a timescale of a few ps. A variation of ±0.1 to 0.2 eV of the electronic properties with the ion dynamics is found, which increases upon increasing the temp.
- 43Carignano, M. A.; Kachmar, A.; Hutter, J. Thermal effects on CH3NH3PbI3 perovskite from ab initio molecular dynamics simulations J. Phys. Chem. C 2015, 119, 8991– 8997 DOI: 10.1021/jp510568nGoogle Scholar43https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXjtlChtLY%253D&md5=c17bae31ceef67cc99b7c4c1df6699cdThermal Effects on CH3NH3PbI3 Perovskite from Ab Initio Molecular Dynamics SimulationsCarignano, Marcelo A.; Kachmar, Ali; Hutter, JurgJournal of Physical Chemistry C (2015), 119 (17), 8991-8997CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)We present a mol. dynamics simulation study of CH3NH3PbI3 based on forces calcd. from d. functional theory. The simulations were performed on model systems having 8 and 27 unit cells, and for a total simulation time of 40 ps in each case. Anal. of the finite size effects, in particular the mobility of the org. component, suggests that the smaller system is over-correlated through the long-range electrostatic interaction. In the larger system, this finite size artifact is relaxed, producing a more reliable description of the anisotropic rotational behavior of the methylammonium mols. The thermal effects on the optical properties of the system were also analyzed. The HOMO-LUMO energy gap fluctuates around its central value with a std. deviation of approx. 0.1 eV. The projected d. of states consistently place the Fermi level on the p orbitals of the I atoms and the lowest virtual state on the p orbitals of the Pb atoms throughout the whole simulation trajectory.
- 44Goehry, C.; Nemnes, G. A.; Manolescu, A. Collective behavior of molecular dipoles in CH3NH3PbI3 J. Phys. Chem. C 2015, 119, 19674– 19680 DOI: 10.1021/acs.jpcc.5b05823Google Scholar44https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXht12ks7vE&md5=2137534639fef0fc2643bd2bb1dc7f0eCollective Behavior of Molecular Dipoles in CH3NH3PbI3Goehry, C.; Nemnes, G. A.; Manolescu, A.Journal of Physical Chemistry C (2015), 119 (34), 19674-19680CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Using ab initio DFT-LDA mol. dynamics simulations the authors studied the thermal motion occurring in perovskite crystals of CH3NH3PbI3. They obtained ests. of the rotational relaxation time of the cation CH3NH3+. We examine the tetragonal and cubic phases, as both may be present under operational conditions. Influenced by each other, and by the tilting of PbI6 octahedra, cations undergo collective motion as their contribution to polarization does not vanish. The modus operandi of formation of microscopic ferroelec. domains is qual. described.
- 45Mattoni, A.; Filippetti, A.; Saba, M. I.; Delugas, P. Methylammonium rotational dynamics in lead halide perovskite by classical molecular dynamics: the role of temperature J. Phys. Chem. C 2015, 119, 17421– 17428 DOI: 10.1021/acs.jpcc.5b04283Google Scholar45https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtVaktb%252FM&md5=a539f35a182f65b105bd37c86e4992ebMethylammonium Rotational Dynamics in Lead Halide Perovskite by Classical Molecular Dynamics: The Role of TemperatureMattoni, A.; Filippetti, A.; Saba, M. I.; Delugas, P.Journal of Physical Chemistry C (2015), 119 (30), 17421-17428CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)An interat. model potential for mol. dynamics is derived from first-principles and used to study the mol. rotations and relaxation times in methylammonium lead halide, here considered the prototypical example of a hybrid crystal with a strong reorientational dynamics. Within the limits of a simple ionic scheme, the potential is able to catch the main qual. features of the material at zero and finite temp. and opens the way to the development of classical potentials for hybrid perovskites. In agreement with expts. and previous theor. findings, the mol. trajectories exhibit a transition from a dynamics dominated by high symmetry directions at low temp. to a fast dynamics at room temp. in which the mol. can reorient quasi-randomly. By computing the angular time correlation function we discuss the reorientational time as a function of temp. in comparison with existing literature, providing a simple model and a clear attribution of the relaxation times in terms of their temp. dependence. This work clarifies the temp. dependence of the relaxation times and the interpretation of the exptl. data in terms of the different mechanisms contributing to the mol. dynamics.
- 46Lahnsteiner, J.; Kresse, G.; Kumar, A.; Sarma, D. D.; Franchini, C.; Bokdam, M. Room-temperature dynamic correlation between methylammonium molecules in lead-iodine based perovskites: An ab initio molecular dynamics perspective Phys. Rev. B: Condens. Matter Mater. Phys. 2016, 94, 214114 DOI: 10.1103/PhysRevB.94.214114Google Scholar46https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXpt1Cru7s%253D&md5=b2cdc4cf471140853e03fbdf7a657607Room-temperature dynamic correlation between methylammonium molecules in lead-iodine based perovskites: an ab initio molecular dynamics perspectiveLahnsteiner, Jonathan; Kresse, Georg; Kumar, Abhinav; Sarma, D. D.; Franchini, Cesare; Bokdam, MennoPhysical Review B (2016), 94 (21), 214114/1-214114/10CODEN: PRBHB7; ISSN:2469-9950. (American Physical Society)The high efficiency of lead organo-metal-halide perovskite solar cells has raised many questions about the role of the methylammonium (MA) mols. in the Pb-I framework. Expts. indicate that the MA mols. are able to "freely" spin around at room temp. even though they carry an intrinsic dipole moment. We have performed large supercell (2592 atoms) finite-temp. ab initio mol. dynamics calcns. to study the correlation between the mols. in the framework. An underlying long-range antiferroelec. ordering of the mol. dipoles is obsd. The dynamical correlation between neighboring mols. shows a max. around room temp. in the mid-temp. phase. In this phase, the rotations are slow enough to (partially) couple to neighbors via the Pb-I cage. This results in a collective motion of neighboring mols. in which the cage acts as the mediator. At lower and higher temps., the motions are less correlated.
- 47Meloni, S.; Moehl, T.; Tress, W.; Franckevičius, M.; Saliba, M.; Lee, Y. H.; Gao, P.; Nazeeruddin, M. K.; Zakeeruddin, S. M.; Rothlisberger, U. Ionic polarization-induced current–voltage hysteresis in CH3NH3PbX3 perovskite solar cells Nat. Commun. 2016, 7, 10334 DOI: 10.1038/ncomms10334Google Scholar47https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XitlChsbc%253D&md5=e09e580b6cf30cd4fa2a52c0732725c3Ionic polarization-induced current-voltage hysteresis in CH3NH3PbX3 perovskite solar cellsMeloni, Simone; Moehl, Thomas; Tress, Wolfgang; Franckevicius, Marius; Saliba, Michael; Lee, Yong Hui; Gao, Peng; Nazeeruddin, Mohammad Khaja; Zakeeruddin, Shaik Mohammed; Rothlisberger, Ursula; Graetzel, MichaelNature Communications (2016), 7 (), 10334CODEN: NCAOBW; ISSN:2041-1723. (Nature Publishing Group)CH3NH3PbX3 (MAPbX3) perovskites have attracted considerable attention as absorber materials for solar light harvesting, reaching solar to power conversion efficiencies above 20%. In spite of the rapid evolution of the efficiencies, the understanding of basic properties of these semiconductors is still ongoing. One phenomenon with so far unclear origin is the so-called hysteresis in the current-voltage characteristics of these solar cells. Here we investigate the origin of this phenomenon with a combined exptl. and computational approach. Exptl. the activation energy for the hysteretic process is detd. and compared with the computational results. First-principles simulations show that the timescale for MA+ rotation excludes a MA-related ferroelec. effect as possible origin for the obsd. hysteresis. On the other hand, the computationally detd. activation energies for halide ion (vacancy) migration are in excellent agreement with the exptl. detd. values, suggesting that the migration of this species causes the obsd. hysteretic behavior of these solar cells.
- 48Kulbak, M.; Gupta, S.; Kedem, N.; Levine, I.; Bendikov, T.; Hodes, G.; Cahen, D. Cesium enhances long-term stability of lead bromide perovskite-based solar cells J. Phys. Chem. Lett. 2016, 7, 167– 172 DOI: 10.1021/acs.jpclett.5b02597Google Scholar48https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXitVygt7rJ&md5=153a43764ddd69522b617fe888a5a387Cesium Enhances Long-Term Stability of Lead Bromide Perovskite-Based Solar CellsKulbak, Michael; Gupta, Satyajit; Kedem, Nir; Levine, Igal; Bendikov, Tatyana; Hodes, Gary; Cahen, DavidJournal of Physical Chemistry Letters (2016), 7 (1), 167-172CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)Direct comparison between perovskite-structured hybrid org.-inorg. methylammonium lead bromide (MAPbBr3) and all-inorg. Cs lead bromide (CsPbBr3), allows identifying possible fundamental differences in their structural, thermal and electronic characteristics. Both materials possess a similar direct optical band gap, but CsPbBr3 demonstrates a higher thermal stability than MAPbBr3. To compare device properties, the authors fabricated solar cells, with similarly synthesized MAPbBr3 or CsPbBr3, over mesoporous TiO2 scaffolds. Both cell types demonstrated comparable photovoltaic performances under AM1.5 illumination, reaching power conversion efficiencies of ∼6% with a poly aryl amine-based deriv. as hole transport material. Further anal. shows that Cs-based devices are as efficient as, and more stable than methylammonium-based ones, after aging (storing the cells for 2 wk in a dry (relative humidity 15-20%) air atm. in the dark) for 2 wk, under const. illumination (at max. power), and under electron beam irradn.
- 49Eperon, G. E.; Paterno, G. M.; Sutton, R. J.; Zampetti, A.; Haghighirad, A. A.; Cacialli, F.; Snaith, H. J. Inorganic caesium lead iodide perovskite solar cells J. Mater. Chem. A 2015, 3, 19688– 19695 DOI: 10.1039/C5TA06398AGoogle Scholar49https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsVGjtbbJ&md5=f62ebbc17b21bfcff5a5e9c2ae6b80e2Inorganic cesium lead iodide perovskite solar cellsEperon, Giles E.; Paterno, Giuseppe M.; Sutton, Rebecca J.; Zampetti, Andrea; Haghighirad, Amir Abbas; Cacialli, Franco; Snaith, Henry J.Journal of Materials Chemistry A: Materials for Energy and Sustainability (2015), 3 (39), 19688-19695CODEN: JMCAET; ISSN:2050-7496. (Royal Society of Chemistry)The vast majority of perovskite solar cell research has focused on org.-inorg. lead trihalide perovskites. Herein, we present working inorg. CsPbI3 perovskite solar cells for the first time. CsPbI3 normally resides in a yellow non-perovskite phase at room temp., but by careful processing control and development of a low-temp. phase transition route we have stabilized the material in the black perovskite phase at room temp. As such, we have fabricated solar cell devices in a variety of architectures, with current-voltage curve measured efficiency up to 2.9% for a planar heterojunction architecture, and stabilized power conversion efficiency of 1.7%. The well-functioning planar junction devices demonstrate long-range electron and hole transport in this material. Importantly, this work identifies that the org. cation is not essential, but simply a convenience for forming lead triiodide perovskites with good photovoltaic properties. We addnl. observe significant rate-dependent current-voltage hysteresis in CsPbI3 devices, despite the absence of the org. polar mol. previously thought to be a candidate for inducing hysteresis via ferroelec. polarization. Due to its space group, CsPbI3 cannot be a ferroelec. material, and thus we can conclude that ferroelectricity is not required to explain current-voltage hysteresis in perovskite solar cells. Our report of working inorg. perovskite solar cells paves the way for further developments likely to lead to much more thermally stable perovskite solar cells and other optoelectronic devices.
- 50Gesi, K. Effect of hydrostatic pressure on the structural phase transitions in CH3NH3PbX3 (X = Cl, Br, I) Ferroelectrics 1997, 203, 249– 268 DOI: 10.1080/00150199708012851Google ScholarThere is no corresponding record for this reference.
- 51Maeda, M.; Hattori, M.; Hotta, A.; Suzuki, I. Dielectric Studies on CH3NH3PbX3 (X = Cl and Br) Single Cystals J. Phys. Soc. Jpn. 1997, 66, 1508– 1511 DOI: 10.1143/JPSJ.66.1508Google Scholar51https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXjs1Cnurg%253D&md5=5c1c573b0511308d91e9960e70ffa948Dielectric studies on CH3NH3PbX3 (X = Cl and Br) single crystalsMaeda, Masaki; Hattori, Maki; Hotta, Akifumi; Suzuki, IkuoJournal of the Physical Society of Japan (1997), 66 (5), 1508-1511CODEN: JUPSAU; ISSN:0031-9015. (Physical Society of Japan)Dielec. dispersion measurements have been performed on CH3NH3PbX3 (MAPbX3, X = Cl and Br) single crystals at frequencies between 50 Hz and 1 MHz. Significant dielec. dispersion was obsd. in the cubic and tetragonal II phases for MAPbCl3 and in the cubic, tetragonal I and tetragonal II phases for MAPbBr3. The apparent dielec. dispersion is attributed to the ionic cond. in the crystals. The static bulk cond. is expressed by the Arrhenius-type formula σ = (A/T)exp(-ΔE/kT). The activation energies for ionic conduction along [100] axis for each phase are estd. to be 0.13 eV (cubic phase) for MAPbCl3 and 0.132 eV (cubic phase) and 1.60 eV (tetragonal I phase) for MAPbBr3.
- 52Chen, Y.-F.; Tsai, Y.-T.; Bassani, D. M.; Hirsch, L. Experimental evidence of the anti-parallel arrangement of methylammonium ions in perovskites Appl. Phys. Lett. 2016, 109, 213504 DOI: 10.1063/1.4968579Google Scholar52https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhvFGru7jJ&md5=5c2ff81a66f64f07da4bf1c24d435b19Experimental evidence of the anti-parallel arrangement of methylammonium ions in perovskitesChen, Yan-Fang; Tsai, Yu-Tang; Bassani, Dario M.; Hirsch, LionelApplied Physics Letters (2016), 109 (21), 213504/1-213504/4CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)Orientation arrangement of methylammonium ions in hybrid org.-inorg. perovskite is still under debate because their tendency for alignment is expected to give rise to either ferroelec. or anti-ferroelec. behavior, which may influence the perovskite device performance. To resolve the debate surrounding the alignment of the org. cations in perovskite materials, we studied the dipole orientation by analyzing the dielec. properties of the material. The dielec. permittivity has been investigated as a function of temp. with the data analyzed using the Kirkwood-Frohlich-Onsager theory. From these results, we provide exptl. evidence of the anti-parallel arrangement of methylammonium ions in hybrid org.-inorg. perovskite. (c) 2016 American Institute of Physics.
- 53Ang, C.; Yu, Z.; Youn, H. J.; Randall, C. A.; Bhalla, A. S.; Cross, L. E.; Nino, J.; Lanagan, M. Low-temperature dielectric relaxation in the pyrochlore (Bi3/4Zn1/4)2(Zn1/4Ta3/4)2O7 compound Appl. Phys. Lett. 2002, 80, 4807– 4809 DOI: 10.1063/1.1486045Google Scholar53https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38Xkslelu7c%253D&md5=6fa5d8bb0eb4787c0687ab296721e24aLow-temperature dielectric relaxation in the pyrochlore (Bi3/4Zn1/4)2(Zn1/4Ta3/4)2O7 compoundAng, Chen; Yu, Zhi; Youn, H. J.; Randall, C. A.; Bhalla, A. S.; Cross, L. E.; Nino, J.; Lanagan, M.Applied Physics Letters (2002), 80 (25), 4807-4809CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)The dielec. behavior of the pyrochlore (Bi3/4Zn1/4)2(Zn1/4Ta3/4)2O7 compd. has been studied. A low-temp. dielec. relaxation was obsd. in a low-permittivity matrix with ε = ∼60. The dielec. relaxation process follows a modified Debye model in the vicinity of the relaxation peak, and the relaxation rate follows the Arrhenius law in the wide frequency range 102 to ∼1010 Hz. The temp. intensity of dielec. peaks are independent of d.c. bias (≤60 kV/cm). The dielec. relaxation is tentatively attributed to the hopping of Zn/Bi ions at A sites with more than one equiv. potential min., and the reorientation of the dipoles probably formed through interactions with the "seventh oxygen" and the Bi/Zn A-site ions in the pyrochlore (Bi3/4Zn1/4)2(Zn1/4Ta3/4)2O7 compd.
- 54Noh, J. H.; Im, S. H.; Heo, J. H.; Mandal, T. N.; Seok, S. I. Chemical management for colorful, efficient, and stable inorganic–organic hybrid nanostructured solar cells Nano Lett. 2013, 13, 1764– 1769 DOI: 10.1021/nl400349bGoogle Scholar54https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXksVyit7w%253D&md5=6279f57e41e3bc9eb469af9b0baa3149Chemical Management for Colorful, Efficient, and Stable Inorganic-Organic Hybrid Nanostructured Solar CellsNoh, Jun Hong; Im, Sang Hyuk; Heo, Jin Hyuck; Mandal, Tarak N.; Seok, Sang IlNano Letters (2013), 13 (4), 1764-1769CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)Chem. tuned inorg.-org. hybrid materials, based on MeNH3(=MA)Pb(I1-xBrx)3 perovskites, have been studied using UV-visible absorption and x-ray diffraction patterns and applied to nanostructured solar cells. The band gap engineering brought about by the chem. management of MAPb(I1-xBrx)3 perovskites can be controllably tuned to cover almost the entire visible spectrum, enabling the realization of colorful solar cells. The authors demonstrate highly efficient solar cells exhibiting 12.3% in a power conversion efficiency of under std. AM 1.5, for the most efficient device, as a result of tunable compn. for the light harvester in conjunction with a mesoporous TiO2 film and a hole conducting polymer. Probably the works highlighted in this paper represent one step toward the realization of low-cost, high-efficiency, and long-term stability with colorful solar cells.
- 55Stoumpos, C. C.; Malliakas, C. D.; Peters, J. A.; Liu, Z.; Sebastian, M.; Im, J.; Chasapis, T. C.; Wibowo, A. C.; Chung, D. Y.; Freeman, A. J. Crystal growth of the perovskite semiconductor CsPbBr3: a new material for high-energy radiation detection Cryst. Growth Des. 2013, 13, 2722– 2727 DOI: 10.1021/cg400645tGoogle Scholar55https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXosFyitLc%253D&md5=615d4e50e40aa9c8cb77e787ec333bb9Crystal Growth of the Perovskite Semiconductor CsPbBr3: A New Material for High-Energy Radiation DetectionStoumpos, Constantinos C.; Malliakas, Christos D.; Peters, John A.; Liu, Zhifu; Sebastian, Maria; Im, Jino; Chasapis, Thomas C.; Wibowo, Arief C.; Chung, Duck Young; Freeman, Arthur J.; Wessels, Bruce W.; Kanatzidis, Mercouri G.Crystal Growth & Design (2013), 13 (7), 2722-2727CODEN: CGDEFU; ISSN:1528-7483. (American Chemical Society)The synthesis, crystal growth, and structural and optoelectronic characterization was carried out for the perovskite compd. CsPbBr3. This compd. is a direct band gap semiconductor which meets most of the requirements for successful detection of X- and γ-ray radiation, such as high attenuation, high resistivity, and significant photocond. response, with detector resoln. comparable to that of com., state-of-the-art materials. A structural phase transition which occurs during crystal growth at higher temp. does not seem to affect its crystal quality. Its μτ product for both hole and electron carriers is approx. equal. The μτ product for electrons is comparable to Cd Zn telluride (CZT) and that for holes is 10 times higher than CZT.
- 56Saidaminov, M. I.; Abdelhady, A. L.; Murali, B.; Alarousu, E.; Burlakov, V. M.; Peng, W.; Dursun, I.; Wang, L.; He, Y.; Maculan, G. High-quality bulk hybrid perovskite single crystals within minutes by inverse temperature crystallization Nat. Commun. 2015, 6, 7586 DOI: 10.1038/ncomms8586Google Scholar56https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC28%252FgvFWltg%253D%253D&md5=8b92f9296104d2abbfc6075816e68ee6High-quality bulk hybrid perovskite single crystals within minutes by inverse temperature crystallizationSaidaminov Makhsud I; Abdelhady Ahmed L; Murali Banavoth; Alarousu Erkki; Peng Wei; Dursun Ibrahim; Maculan Giacomo; Mohammed Omar F; Bakr Osman M; Abdelhady Ahmed L; Burlakov Victor M; Goriely Alain; Wang Lingfei; Wu Tom; He YaoNature communications (2015), 6 (), 7586 ISSN:.Single crystals of methylammonium lead trihalide perovskites (MAPbX3; MA = CH3NH3(+), X = Br(-) or I(-)) have shown remarkably low trap density and charge transport properties; however, growth of such high-quality semiconductors is a time-consuming process. Here we present a rapid crystal growth process to obtain MAPbX3 single crystals, an order of magnitude faster than previous reports. The process is based on our observation of the substantial decrease of MAPbX3 solubility, in certain solvents, at elevated temperatures. The crystals can be both size- and shape-controlled by manipulating the different crystallization parameters. Despite the rapidity of the method, the grown crystals exhibit transport properties and trap densities comparable to the highest quality MAPbX3 reported to date. The phenomenon of inverse or retrograde solubility and its correlated inverse temperature crystallization strategy present a major step forward for advancing the field on perovskite crystallization.
- 57Im, J. H.; Lee, C. R.; Lee, J. W.; Park, S. W.; Park, N. G. 6.5% Efficient perovskite quantum-dot-sensitized solar cell Nanoscale 2011, 3, 4088– 4093 DOI: 10.1039/c1nr10867kGoogle Scholar57https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtlWitr%252FI&md5=21c01ce5d671970b109bd1a98fd6734f6.5% efficient perovskite quantum-dot-sensitized solar cellIm, Jeong-Hyeok; Lee, Chang-Ryul; Lee, Jin-Wook; Park, Sang-Won; Park, Nam-GyuNanoscale (2011), 3 (10), 4088-4093CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)Highly efficient quantum-dot-sensitized solar cell is fabricated using ca. 2-3 nm sized perovskite (CH3NH3)PbI3 nanocrystal. Spin-coating of the equimolar mixt. of CH3NH3I and PbI2 in γ-butyrolactone soln. (perovskite precursor soln.) leads to (CH3NH3)PbI3 quantum dots (QDs) on nanocryst. TiO2 surface. By electrochem. junction with iodide/iodine based redox electrolyte, perovskite QD-sensitized 3.6 μm-thick TiO2 film shows max. external quantum efficiency (EQE) of 78.6% at 530 nm and solar-to-elec. conversion efficiency of 6.54% at AM 1.5G 1 sun intensity (100 mW cm-2), which is by far the highest efficiency among the reported inorg. quantum dot sensitizers.
- 58Kulbak, M.; Cahen, D.; Hodes, G. How important is the organic part of lead halide perovskite photovoltaic cells? Efficient CsPbBr3 cells J. Phys. Chem. Lett. 2015, 6, 2452– 2456 DOI: 10.1021/acs.jpclett.5b00968Google Scholar58https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtVaksb3I&md5=2c21efab962ecdbecd4dfe43526d22cfHow Important Is the Organic Part of Lead Halide Perovskite Photovoltaic Cells? Efficient CsPbBr3 CellsKulbak, Michael; Cahen, David; Hodes, GaryJournal of Physical Chemistry Letters (2015), 6 (13), 2452-2456CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)Hybrid org.-inorg. lead halide perovskite photovoltaic cells have already surpassed 20% conversion efficiency in the few years that they have been seriously studied. However, many fundamental questions still remain unanswered as to why they are so good. One of these is "Is the org. cation really necessary to obtain high quality cells" In this study, we show that an all-inorg. version of the lead bromide perovskite material works equally well as the org. one, in particular generating the high open circuit voltages that are an important feature of these cells.
- 59Blöchl, P. E. Projector augmented-wave method Phys. Rev. B: Condens. Matter Mater. Phys. 1994, 50, 17953– 17979 DOI: 10.1103/PhysRevB.50.17953Google Scholar59https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2sfjslSntA%253D%253D&md5=1853d67af808af2edab58beaab5d3051Projector augmented-wave methodBlochlPhysical review. B, Condensed matter (1994), 50 (24), 17953-17979 ISSN:0163-1829.There is no expanded citation for this reference.
- 60Kresse, G.; Hafner, J. Ab initio molecular dynamics for liquid metals Phys. Rev. B: Condens. Matter Mater. Phys. 1993, 47, 558– 561 DOI: 10.1103/PhysRevB.47.558Google Scholar60https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXlt1Gnsr0%253D&md5=c9074f6e1afc534b260d29dd1846e350Ab initio molecular dynamics of liquid metalsKresse, G.; Hafner, J.Physical Review B: Condensed Matter and Materials Physics (1993), 47 (1), 558-61CODEN: PRBMDO; ISSN:0163-1829.The authors present ab initio quantum-mech. mol.-dynamics calcns. based on the calcn. of the electronic ground state and of the Hellmann-Feynman forces in the local-d. approxn. at each mol.-dynamics step. This is possible using conjugate-gradient techniques for energy minimization, and predicting the wave functions for new ionic positions using sub-space alignment. This approach avoids the instabilities inherent in quantum-mech. mol.-dynamics calcns. for metals based on the use of a factitious Newtonian dynamics for the electronic degrees of freedom. This method gives perfect control of the adiabaticity and allows one to perform simulations over several picoseconds.
- 61Kresse, G.; Furthmüller, J. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set Phys. Rev. B: Condens. Matter Mater. Phys. 1996, 54, 11169– 11186 DOI: 10.1103/PhysRevB.54.11169Google Scholar61https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28Xms1Whu7Y%253D&md5=9c8f6f298fe5ffe37c2589d3f970a697Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis setKresse, G.; Furthmueller, J.Physical Review B: Condensed Matter (1996), 54 (16), 11169-11186CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)The authors present an efficient scheme for calcg. the Kohn-Sham ground state of metallic systems using pseudopotentials and a plane-wave basis set. In the first part the application of Pulay's DIIS method (direct inversion in the iterative subspace) to the iterative diagonalization of large matrixes will be discussed. This approach is stable, reliable, and minimizes the no. of order Natoms3 operations. In the second part, we will discuss an efficient mixing scheme also based on Pulay's scheme. A special "metric" and a special "preconditioning" optimized for a plane-wave basis set will be introduced. Scaling of the method will be discussed in detail for non-self-consistent and self-consistent calcns. It will be shown that the no. of iterations required to obtain a specific precision is almost independent of the system size. Altogether an order Natoms2 scaling is found for systems contg. up to 1000 electrons. If we take into account that the no. of k points can be decreased linearly with the system size, the overall scaling can approach Natoms. They have implemented these algorithms within a powerful package called VASP (Vienna ab initio simulation package). The program and the techniques have been used successfully for a large no. of different systems (liq. and amorphous semiconductors, liq. simple and transition metals, metallic and semiconducting surfaces, phonons in simple metals, transition metals, and semiconductors) and turned out to be very reliable.
- 62Kresse, G.; Joubert, D. From ultrasoft pseudopotentials to the projector augmented-wave method Phys. Rev. B: Condens. Matter Mater. Phys. 1999, 59, 1758– 1775 DOI: 10.1103/PhysRevB.59.1758Google Scholar62https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXkt12nug%253D%253D&md5=78a73e92a93f995982fc481715729b14From ultrasoft pseudopotentials to the projector augmented-wave methodKresse, G.; Joubert, D.Physical Review B: Condensed Matter and Materials Physics (1999), 59 (3), 1758-1775CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)The formal relationship between ultrasoft (US) Vanderbilt-type pseudopotentials and Blochl's projector augmented wave (PAW) method is derived. The total energy functional for US pseudopotentials can be obtained by linearization of two terms in a slightly modified PAW total energy functional. The Hamilton operator, the forces, and the stress tensor are derived for this modified PAW functional. A simple way to implement the PAW method in existing plane-wave codes supporting US pseudopotentials is pointed out. In addn., crit. tests are presented to compare the accuracy and efficiency of the PAW and the US pseudopotential method with relaxed-core all-electron methods. These tests include small mols. (H2, H2O, Li2, N2, F2, BF3, SiF4) and several bulk systems (diamond, Si, V, Li, Ca, CaF2, Fe, Co, Ni). Particular attention is paid to the bulk properties and magnetic energies of Fe, Co, and Ni.
- 63Perdew, J. P.; Ruzsinszky, A.; Csonka, G. I.; Vydrov, O. A.; Scuseria, G. E.; Constantin, L. A.; Zhou, X.; Burke, K. Restoring the density-gradient expansion for exchange in solids and surfaces Phys. Rev. Lett. 2008, 100, 136406 DOI: 10.1103/PhysRevLett.100.136406Google Scholar63https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXktlygt7c%253D&md5=bb5e35a295ab7af85d65ac410d6f898cRestoring the Density-Gradient Expansion for Exchange in Solids and SurfacesPerdew, John P.; Ruzsinszky, Adrienn; Csonka, Gabor I.; Vydrov, Oleg A.; Scuseria, Gustavo E.; Constantin, Lucian A.; Zhou, Xiaolan; Burke, KieronPhysical Review Letters (2008), 100 (13), 136406/1-136406/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)Popular modern generalized gradient approxns. are biased toward the description of free-atom energies. Restoration of the first-principles gradient expansion for exchange over a wide range of d. gradients eliminates this bias. We introduce a revised Perdew-Burke-Ernzerhof generalized gradient approxn. that improves equil. properties of densely packed solids and their surfaces.
- 64Allen, M. P.; Tildesley, D. J. Computer Simulation of Liquids; Oxford University Press, 1991.Google ScholarThere is no corresponding record for this reference.
Cited By
Smart citations by scite.ai include citation statements extracted from the full text of the citing article. The number of the statements may be higher than the number of citations provided by ACS Publications if one paper cites another multiple times or lower if scite has not yet processed some of the citing articles.
This article is cited by 121 publications.
- Gabrielius Rimkus, Sergejus Balčiu̅nas, Hanna R. Petrosova, Olesia I. Kucheriv, Rokas Lemežis, Vytautas Klimavičius, Vidmantas Kalendra, Ju̅ras Banys, Il’ya A. Gural’skiy, Mantas Šimėnas. B-Site Mixing Effects in Hybrid Perovskites: Phase Transitions and Dielectric Response of MAPb1–xSnxBr3. Chemistry of Materials 2025, 37
(3)
, 1314-1320. https://doi.org/10.1021/acs.chemmater.4c03381
- Bong Woo Kim, Sang Hyuk Im. Supersaturated Antisolvent-Assisted Crystallization for Highly Efficient Inorganic Perovskite Light-Emitting Diodes. ACS Nano 2024, 18
(42)
, 28691-28699. https://doi.org/10.1021/acsnano.4c06465
- Gabrielius Rimkus, Sergejus Balčiu̅nas, Maciej Ptak, Szymon Smółka, Vytautas Klimavičius, Daria Szewczyk, Adam Sieradzki, Vidmantas Kalendra, Ju̅ras Banys, Mirosław Mączka, Mantas Šimėnas. Phase Diagram and Dielectric Response of Hybrid Lead Halide Hollow Perovskites: A Universal Behavior of Molecular Cation Mixing. Chemistry of Materials 2024, 36
(15)
, 7397-7405. https://doi.org/10.1021/acs.chemmater.4c01346
- Debasmita Pariari, Paribesh Acharyya, Arijit Sinha, Ashutosh Mohanty, Shaili Sett, Navkiranjot Kaur Gill, Arindam Ghosh, Umesh V. Waghmare, Kanishka Biswas, D. D. Sarma. Non-monotonic Thermal Conductivity of FAxMA1–xPbI3 Achieving Ultralow Values: The Role of Anharmonic Low Energy Rotation of Organic Moieties. ACS Energy Letters 2024, 9
(5)
, 2128-2136. https://doi.org/10.1021/acsenergylett.4c00047
- Mantas Simenas, Anna Gagor, Juras Banys, Miroslaw Maczka. Phase Transitions and Dynamics in Mixed Three- and Low-Dimensional Lead Halide Perovskites. Chemical Reviews 2024, 124
(5)
, 2281-2326. https://doi.org/10.1021/acs.chemrev.3c00532
- Chenyang Yu, Yukinobu Kawakita, Tatsuya Kikuchi, Maiko Kofu, Takashi Honda, Zhe Zhang, Zhao Zhang, Yucheng Liu, Shengzhong Frank Liu, Bing Li. Atomic Structure and Dynamics of Organic–Inorganic Hybrid Perovskite Formamidinium Lead Iodide. The Journal of Physical Chemistry Letters 2024, 15
(1)
, 329-338. https://doi.org/10.1021/acs.jpclett.3c02498
- Xia Liang, Johan Klarbring, William J. Baldwin, Zhenzhu Li, Gábor Csányi, Aron Walsh. Structural Dynamics Descriptors for Metal Halide Perovskites. The Journal of Physical Chemistry C 2023, 127
(38)
, 19141-19151. https://doi.org/10.1021/acs.jpcc.3c03377
- Debasmita Pariari, Sakshi Mehta, Sayak Mandal, Arup Mahata, Titas Pramanik, Sujit Kamilya, Arya Vidhan, Tayur N. Guru Row, Pralay K. Santra, Shaibal K. Sarkar, Filippo De Angelis, Abhishake Mondal, D. D. Sarma. Realizing the Lowest Bandgap and Exciton Binding Energy in a Two-Dimensional Lead Halide System. Journal of the American Chemical Society 2023, 145
(29)
, 15896-15905. https://doi.org/10.1021/jacs.3c03300
- Yujing Wei, Artem G. Volosniev, Dusan Lorenc, Ayan A. Zhumekenov, Osman M. Bakr, Mikhail Lemeshko, Zhanybek Alpichshev. Bond Polarizability as a Probe of Local Crystal Fields in Hybrid Lead-Halide Perovskites. The Journal of Physical Chemistry Letters 2023, 14
(27)
, 6309-6314. https://doi.org/10.1021/acs.jpclett.3c01158
- F. B. Minussi, R. M. da Silva Jr, E. B. Araújo. Differing Effects of Mixed A-Site Composition on the Properties of Hybrid Lead Iodide Perovskites. The Journal of Physical Chemistry C 2023, 127
(18)
, 8814-8824. https://doi.org/10.1021/acs.jpcc.3c01179
- Mantas Šimėnas, Sergejus Balčiu̅nas, Anna Ga̧gor, Agnieszka Pienia̧żek, Kasper Tolborg, Martynas Kinka, Vytautas Klimavicius, Šaru̅nas Svirskas, Vidmantas Kalendra, Maciej Ptak, Daria Szewczyk, Artur P. Herman, Robert Kudrawiec, Adam Sieradzki, Robertas Grigalaitis, Aron Walsh, Mirosław Ma̧czka, Ju̅ras Banys. Mixology of MA1–xEAxPbI3 Hybrid Perovskites: Phase Transitions, Cation Dynamics, and Photoluminescence. Chemistry of Materials 2022, 34
(22)
, 10104-10112. https://doi.org/10.1021/acs.chemmater.2c02807
- V. K. Sharma, R. Mukhopadhyay, A. Mohanty, V. García Sakai, M. Tyagi, D. D. Sarma. Influence of the Halide Ion on the A-Site Dynamics in FAPbX3 (X = Br and Cl). The Journal of Physical Chemistry C 2022, 126
(16)
, 7158-7168. https://doi.org/10.1021/acs.jpcc.2c00968
- Menno Bokdam, Jonathan Lahnsteiner, D. D. Sarma. Exploring Librational Pathways with on-the-Fly Machine-Learning Force Fields: Methylammonium Molecules in MAPbX3 (X = I, Br, Cl) Perovskites. The Journal of Physical Chemistry C 2021, 125
(38)
, 21077-21086. https://doi.org/10.1021/acs.jpcc.1c06835
- John L. Lyons. Effective Donor Dopants for Lead Halide Perovskites. Chemistry of Materials 2021, 33
(15)
, 6200-6205. https://doi.org/10.1021/acs.chemmater.1c01898
- Amrita Dey, Junzhi Ye, Apurba De, Elke Debroye, Seung Kyun Ha, Eva Bladt, Anuraj S. Kshirsagar, Ziyu Wang, Jun Yin, Yue Wang, Li Na Quan, Fei Yan, Mengyu Gao, Xiaoming Li, Javad Shamsi, Tushar Debnath, Muhan Cao, Manuel A. Scheel, Sudhir Kumar, Julian A. Steele, Marina Gerhard, Lata Chouhan, Ke Xu, Xian-gang Wu, Yanxiu Li, Yangning Zhang, Anirban Dutta, Chuang Han, Ilka Vincon, Andrey L. Rogach, Angshuman Nag, Anunay Samanta, Brian A. Korgel, Chih-Jen Shih, Daniel R. Gamelin, Dong Hee Son, Haibo Zeng, Haizheng Zhong, Handong Sun, Hilmi Volkan Demir, Ivan G. Scheblykin, Iván Mora-Seró, Jacek K. Stolarczyk, Jin Z. Zhang, Jochen Feldmann, Johan Hofkens, Joseph M. Luther, Julia Pérez-Prieto, Liang Li, Liberato Manna, Maryna I. Bodnarchuk, Maksym V. Kovalenko, Maarten B. J. Roeffaers, Narayan Pradhan, Omar F. Mohammed, Osman M. Bakr, Peidong Yang, Peter Müller-Buschbaum, Prashant V. Kamat, Qiaoliang Bao, Qiao Zhang, Roman Krahne, Raquel E. Galian, Samuel D. Stranks, Sara Bals, Vasudevanpillai Biju, William A. Tisdale, Yong Yan, Robert L. Z. Hoye, Lakshminarayana Polavarapu. State of the Art and Prospects for Halide Perovskite Nanocrystals. ACS Nano 2021, 15
(7)
, 10775-10981. https://doi.org/10.1021/acsnano.0c08903
- V. K. Sharma, R. Mukhopadhyay, A. Mohanty, V. García Sakai, M. Tyagi, D. D. Sarma. Contrasting Effects of FA Substitution on MA/FA Rotational Dynamics in FAxMA1–xPbI3. The Journal of Physical Chemistry C 2021, 125
(24)
, 13666-13676. https://doi.org/10.1021/acs.jpcc.1c03280
- Priya Srivastava, Ramesh Kumar, Monojit Bag. Discerning the Role of an A-Site Cation and X-Site Anion for Ion Conductivity Tuning in Hybrid Perovskites by Photoelectrochemical Impedance Spectroscopy. The Journal of Physical Chemistry C 2021, 125
(1)
, 211-222. https://doi.org/10.1021/acs.jpcc.0c09443
- Sudip Chakraborty, Mohammad Khaja Nazeeruddin. The Status Quo of Rashba Phenomena in Organic–Inorganic Hybrid Perovskites. The Journal of Physical Chemistry Letters 2021, 12
(1)
, 361-367. https://doi.org/10.1021/acs.jpclett.0c02497
- V. K. Sharma, R. Mukhopadhyay, A. Mohanty, M. Tyagi, J. P. Embs, D. D. Sarma. Contrasting Behaviors of FA and MA Cations in APbBr3. The Journal of Physical Chemistry Letters 2020, 11
(22)
, 9669-9679. https://doi.org/10.1021/acs.jpclett.0c02688
- Qiao Kong, Amael Obliger, Minliang Lai, Mengyu Gao, David T. Limmer, Peidong Yang. Solid-State Ionic Rectification in Perovskite Nanowire Heterostructures. Nano Letters 2020, 20
(11)
, 8151-8156. https://doi.org/10.1021/acs.nanolett.0c03204
- Ethan Berger, Julia Wiktor, Alfredo Pasquarello. Low-Frequency Dielectric Response of Tetragonal Perovskite CH3NH3PbI3. The Journal of Physical Chemistry Letters 2020, 11
(15)
, 6279-6285. https://doi.org/10.1021/acs.jpclett.0c00418
- Pronoy Nandi, S. K. Pandey, Chandan Giri, Vijay Singh, L. Petaccia, U. Manju, Subhendra D. Mahanti, D. Topwal. Probing the Electronic Structure of Hybrid Perovskites in the Orientationally Disordered Cubic Phase. The Journal of Physical Chemistry Letters 2020, 11
(14)
, 5719-5727. https://doi.org/10.1021/acs.jpclett.0c01386
- Dong-Ho Kang, Seul-Gi Kim, Yong Churl Kim, In Taek Han, Ho Jin Jang, Jun Yeob Lee, Nam-Gyu Park. CsPbBr3/CH3NH3PbCl3 Double Layer Enhances Efficiency and Lifetime of Perovskite Light-Emitting Diodes. ACS Energy Letters 2020, 5
(7)
, 2191-2199. https://doi.org/10.1021/acsenergylett.0c01036
- Weiwei Li, Zhenyong Man, Jiangtao Zeng, Liaoying Zheng, Guorong Li, Abdelhadi Kassiba. Relationship of Giant Dielectric Constant and Ion Migration in CH3NH3PbI3 Single Crystal Using Dielectric Spectroscopy. The Journal of Physical Chemistry C 2020, 124
(24)
, 13348-13355. https://doi.org/10.1021/acs.jpcc.0c02971
- Qian Zhao, Abhijit Hazarika, Laura T. Schelhas, Jun Liu, E. Ashley Gaulding, Guoran Li, Minghui Zhang, Michael F. Toney, Peter C. Sercel, Joseph M. Luther. Size-Dependent Lattice Structure and Confinement Properties in CsPbI3 Perovskite Nanocrystals: Negative Surface Energy for Stabilization. ACS Energy Letters 2020, 5
(1)
, 238-247. https://doi.org/10.1021/acsenergylett.9b02395
- Abhishek Maiti, Salma Khatun, Amlan J. Pal. Rashba Band Splitting in CH3NH3PbI3: An Insight from Spin-Polarized Scanning Tunneling Spectroscopy. Nano Letters 2020, 20
(1)
, 292-299. https://doi.org/10.1021/acs.nanolett.9b03800
- Ashutosh Mohanty, Diptikanta Swain, Sharada Govinda, Tayur N. Guru Row, D. D. Sarma. Phase Diagram and Dielectric Properties of MA1–xFAxPbI3. ACS Energy Letters 2019, 4
(9)
, 2045-2051. https://doi.org/10.1021/acsenergylett.9b01291
- Valentina
M. Caselli, Mathias Fischer, Daniele Meggiolaro, Edoardo Mosconi, Filippo De Angelis, Samuel D. Stranks, Andreas Baumann, Vladimir Dyakonov, Eline M. Hutter, Tom J. Savenije. Charge Carriers Are Not Affected by the Relatively Slow-Rotating Methylammonium Cations in Lead Halide Perovskite Thin Films. The Journal of Physical Chemistry Letters 2019, 10
(17)
, 5128-5134. https://doi.org/10.1021/acs.jpclett.9b02160
- Casey
L. Kennedy, Andrew H. Hill, Erik M. Grumstrup. Screening Links Transport and Recombination Mechanisms in Lead Halide Perovskites. The Journal of Physical Chemistry C 2019, 123
(25)
, 15827-15833. https://doi.org/10.1021/acs.jpcc.9b03235
- Sudeep Maheshwari, Magnus B. Fridriksson, Sayan Seal, Jörg Meyer, Ferdinand C. Grozema. The Relation between Rotational Dynamics of the Organic Cation and Phase Transitions in Hybrid Halide Perovskites. The Journal of Physical Chemistry C 2019, 123
(23)
, 14652-14661. https://doi.org/10.1021/acs.jpcc.9b02736
- Andrew
R. Warwick, Jorge Íñiguez, Peter D. Haynes, Nicholas C. Bristowe. First-Principles Study of Ferroelastic Twins in Halide Perovskites. The Journal of Physical Chemistry Letters 2019, 10
(6)
, 1416-1421. https://doi.org/10.1021/acs.jpclett.9b00202
- Wissam A. Saidi, Ali Kachmar. Effects of Electron–Phonon Coupling on Electronic Properties of Methylammonium Lead Iodide Perovskites. The Journal of Physical Chemistry Letters 2018, 9
(24)
, 7090-7097. https://doi.org/10.1021/acs.jpclett.8b03164
- Laura M. Herz. How Lattice Dynamics Moderate the Electronic Properties of Metal-Halide Perovskites. The Journal of Physical Chemistry Letters 2018, 9
(23)
, 6853-6863. https://doi.org/10.1021/acs.jpclett.8b02811
- Prescott
E. Evans, Maren Pink, Ayan A. Zhumekenov, Guanhua Hao, Yaroslav Losovyj, Osman M. Bakr, Peter A. Dowben, Andrew J. Yost. Rotationally Free and Rigid Sublattices of the Single Crystal Perovskite CH3NH3PbBr3 (001): The Case of the Lattice Polar Liquid. The Journal of Physical Chemistry C 2018, 122
(44)
, 25506-25514. https://doi.org/10.1021/acs.jpcc.8b08994
- Pronoy Nandi, Chandan Giri, Diptikanta Swain, U. Manju, Subhendra D. Mahanti, Dinesh Topwal. Temperature Dependent Photoinduced Reversible Phase Separation in Mixed-Halide Perovskite. ACS Applied Energy Materials 2018, 1
(8)
, 3807-3814. https://doi.org/10.1021/acsaem.8b00587
- Kento Yamada, Ryosuke Nishikubo, Hikaru Oga, Yuhei Ogomi, Shuzi Hayase, Shohei Kanno, Yutaka Imamura, Masahiko Hada, Akinori Saeki. Anomalous Dielectric Behavior of a Pb/Sn Perovskite: Effect of Trapped Charges on Complex Photoconductivity. ACS Photonics 2018, 5
(8)
, 3189-3197. https://doi.org/10.1021/acsphotonics.8b00422
- Sharada Govinda, Bhushan P. Kore, Pratibha Mahale, Anshu Pandey, D. D. Sarma. Can SHG Measurements Determine the Polarity of Hybrid Lead Halide Perovskites?. ACS Energy Letters 2018, 3
(8)
, 1887-1891. https://doi.org/10.1021/acsenergylett.8b00999
- Francesco Cordero, Floriana Craciun, Francesco Trequattrini, Patrizia Imperatori, Anna Maria Paoletti, Giovanna Pennesi. Competition between Polar and Antiferrodistortive Modes and Correlated Dynamics of the Methylammonium Molecules in MAPbI3 from Anelastic and Dielectric Measurements. The Journal of Physical Chemistry Letters 2018, 9
(15)
, 4401-4406. https://doi.org/10.1021/acs.jpclett.8b01761
- Sharada Govinda, Bhushan P. Kore, Diptikanta Swain, Akmal Hossain, Chandan De, Tayur N. Guru Row, D. D. Sarma. Critical Comparison of FAPbX3 and MAPbX3 (X = Br and Cl): How Do They Differ?. The Journal of Physical Chemistry C 2018, 122
(25)
, 13758-13766. https://doi.org/10.1021/acs.jpcc.8b00602
- Benjamin T. Diroll, Peijun Guo, and Richard D. Schaller . Unique Optical Properties of Methylammonium Lead Iodide Nanocrystals Below the Bulk Tetragonal-Orthorhombic Phase Transition. Nano Letters 2018, 18
(2)
, 846-852. https://doi.org/10.1021/acs.nanolett.7b04099
- Huan Yang, Bing Sun, Junjie Guan, Shun-Da Wu, Peihan Wang, Qiang Wang, Jialiang Xu, Hao-Li Zhang. Chiral 0D hybrid lead-bromide perovskites with strong nonlinear chiroptical properties. Materials Chemistry Frontiers 2025, 9
(3)
, 418-429. https://doi.org/10.1039/D4QM00627E
- Naveen Kumar Tailor, Rohit Kumar Rohj, Krishanu Dey, Samuel D. Stranks, D. D. Sarma, Soumitra Satapathi. Unraveling low-temperature structural and dielectric characteristics in lead-free bismuth halide perovskites. Journal of Materials Chemistry C 2025, 13
(2)
, 918-927. https://doi.org/10.1039/D4TC03414G
- Henning Kuper, Becker Jörg August. Ab initio study of surfaces of lead and tin based metal halide perovskite structures. Zeitschrift für Physikalische Chemie 2024, 238
(12)
, 2249-2270. https://doi.org/10.1515/zpch-2024-0616
- Jian Wang, Shanshan Yu, Handong Jin, Yu Li, Kai Zhang, David Lee Phillips, Shihe Yang. Nonstoichiometry Promoted Solventless Recrystallization of a Thick and Compact CsPbBr
3
Film for Real‐Time Dynamic X‐Ray Imaging. Advanced Science 2024, 11
(46)
https://doi.org/10.1002/advs.202407314
- Agustin O. Alvarez, Marisé García‐Batlle, Ferdinand Lédée, Eric Gros‐Daillon, Javier Mayén Guillén, Jean‐Marie Verilhac, Thibault Lemercier, Julien Zaccaro, Lluis F. Marsal, Osbel Almora, Germà Garcia‐Belmonte. Ion Migration and Space‐Charge Zones in Metal Halide Perovskites Through Short‐Circuit Transient Current and Numerical Simulations. Advanced Electronic Materials 2024, 10
(11)
https://doi.org/10.1002/aelm.202400241
- Furqanul Hassan Naqvi, Syed Bilal Junaid, Jae-Hyeon Ko, Yeong Uk Choi, Jong Hoon Jung, Wonhyuk Shon, Seongsu Lee. Dynamics of glassy state in MAPbBr3-xClx mixed lead halide perovskites. Ceramics International 2024, 50
(20)
, 40136-40150. https://doi.org/10.1016/j.ceramint.2024.07.399
- F. B. Minussi, R. M. Silva, J. C. S. Moraes, E. B. Araújo. Organic cations in halide perovskite solid solutions: exploring beyond size effects. Physical Chemistry Chemical Physics 2024, 26
(31)
, 20770-20784. https://doi.org/10.1039/D4CP02419B
- Marianna Testa, Antonio De Santis, Gemma Tinti, Alessandro Paoloni, Giuseppe Papalino, Giulietto Felici, Zaza Chubinidze, Fabio Matteocci, Matthias Auf der Maur, Silvia Rizzato, Leonardo Lo Presti, Ilenia Viola, Silvio Morganti, Chiara Rovelli. Direct detection of minimum ionizing charged particles in a perovskite single crystal detector with single particle sensitivity. Nanoscale 2024, 16
(27)
, 12918-12922. https://doi.org/10.1039/D4NR01556H
- Raja Sekhar Muddam, Joseph Sinclair, Lethy Krishnan Jagadamma. Piezoelectric Charge Coefficient of Halide Perovskites. Materials 2024, 17
(13)
, 3083. https://doi.org/10.3390/ma17133083
- Taame Abraha Berhe, Wei-Nien Su, Bing Joe Hwang. Halide Perovskites’ Multifunctional Properties: Coordination Engineering, Coordination Chemistry, Electronic Interactions and Energy Applications beyond Photovoltaics. Inorganics 2024, 12
(7)
, 182. https://doi.org/10.3390/inorganics12070182
- Fernando P. Sabino, Xin Gang Zhao, Gustavo M. Dalpian, Alex Zunger. Impact of symmetry breaking and spin-orbit coupling on the band gap of halide perovskites. Physical Review B 2024, 110
(3)
https://doi.org/10.1103/PhysRevB.110.035160
- Idan Cohen, Małgorzata Wierzbowska, Ben Aizenshtein, Lioz Etgar. Tracking the Dimensionality Transition from a Three Dimensional Single Crystal to a Two Dimensional Perovskite. ChemNanoMat 2024, 10
(6)
https://doi.org/10.1002/cnma.202300625
- Songyuan Li, Gang Zhao, Xinhang Sun, Jiale Zheng, Junhui Liu, Mingju Huang. Highly sensitive and selective fluorescent “turn-on” sensor for Ag+ detection using MAPbBr3@PCN-221(Fe): An efficient Ag+-bridged energy transfer from perovskite to MOF. The Journal of Chemical Physics 2024, 160
(18)
https://doi.org/10.1063/5.0207983
- Sauraj Jha, Ross Haroldson, Anvar A. Zakhidov, Jason D. Slinker. Dielectric constants and double-layer formation in a perovskite thin film revealed by electrochemical impedance spectroscopy. MRS Communications 2024, 14
(2)
, 196-200. https://doi.org/10.1557/s43579-023-00495-3
- Konstantinos Papadopoulos, Ola Kenji Forslund, Stephen Cottrell, Koji Yokoyama, Pabitra K. Nayak, Francoise M. Amombo Noa, Lars Öhrström, Elisabetta Nocerino, Lars Börjesson, Jun Sugiyama, Martin Månsson, Yasmine Sassa. Photophysical Ion Dynamics in Hybrid Perovskite MAPbX
3
(X=Br, Cl) Single Crystals. Advanced Physics Research 2024, 3
(3)
https://doi.org/10.1002/apxr.202300120
- Sauraj Jha, Ross Haroldson, Anvar A. Zakhidov, Jason D. Slinker. The Synergetic Ionic and Electronic Features of MAPbI
3
Perovskite Films Revealed by Electrochemical Impedance Spectroscopy. Advanced Optical Materials 2024, 12
(4)
https://doi.org/10.1002/adom.202301677
- Florent Pawula, Ali Fakih, Stanislav Péchev, Ramzy Daou, Daniele Mantione, Oleg Lebedev, Antoine Maignan, Georges Hadziioannou, Sylvie Hébert, Guillaume Fleury. Structural, optical, and electronic properties of single crystals of 4H lead-based hexagonal hybrid perovskite. Physical Review Materials 2024, 8
(2)
https://doi.org/10.1103/PhysRevMaterials.8.025403
- Zhiguo Wang, Shengwen Shu, Xiaoyong Wei, Renhong Liang, Shanming Ke, Longlong Shu, Gustau Catalan. Flexophotovoltaic Effect and Above-Band-Gap Photovoltage Induced by Strain Gradients in Halide Perovskites. Physical Review Letters 2024, 132
(8)
https://doi.org/10.1103/PhysRevLett.132.086902
- Fernando Brondani Minussi, Rogério Marcos Silva, Eudes Borges Araújo. Composition‐Property Relations for GA
x
FA
y
MA
1‐
x
‐
y
PbI
3
Perovskites. Small 2024, 20
(7)
https://doi.org/10.1002/smll.202305054
- Ruiqi Wu, Alex M. Ganose. Relativistic electronic structure and photovoltaic performance of K
2
CsSb. Journal of Materials Chemistry A 2023, 11
(40)
, 21636-21644. https://doi.org/10.1039/D3TA02061D
- Chung Hyeon Jang, Ye In Kim, Amit Kumar Harit, Jung Min Ha, Sejeong Park, Young Wook Noh, Ah‐young Lee, Kyeong Su Kim, Jae Woong Jung, Han Young Woo, Myoung Hoon Song. Multifunctional Conjugated Molecular Additives for Highly Efficient Perovskite Light‐Emitting Diodes. Advanced Materials 2023, 35
(24)
https://doi.org/10.1002/adma.202210511
- Lars Freter, Hung-Chang Hsu, Raman Sankar, Chun-Wei Chen, Rafal E. Dunin-Borkowski, Philipp Ebert, Ya-Ping Chiu, Michael Schnedler. Interplay of field-induced molecular dipole alignment and compensating surface polarization in low-temperature
P
−
V
hysteresis of
MAPbBr
3
(
001
)
. Physical Review Materials 2023, 7
(5)
https://doi.org/10.1103/PhysRevMaterials.7.L052401
- Meysam Salari, Nello D. Sansone, Zahir Razzaz, Sara Mohseni Taromsari, Matthew Leroux, Chul B. Park, Patrick C. Lee. Insights into synergy-induced multifunctional property enhancement mechanisms in hybrid graphene nanoplatelet reinforced polymer composites. Chemical Engineering Journal 2023, 463 , 142406. https://doi.org/10.1016/j.cej.2023.142406
- Hua Li, Chao Ding, Dong Liu, Shota Yajima, Kei Takahashi, Shuzi Hayase, Qing Shen. Efficient Charge Transfer in MAPbI3 QDs/TiO2 Heterojunctions for High-Performance Solar Cells. Nanomaterials 2023, 13
(7)
, 1292. https://doi.org/10.3390/nano13071292
- Huajun Guo, Shenghui Yi, Shuai Yang, Yinan Jiao, Shengjian Qin, Rui Li, Ye Wang, Hao Li, Yuanhua Xia, Yang Zhang, Zishang Liang, Rongrong Yan, Huan Liu, Jinjin Zhao. Structural Symmetry Impressing Carrier Dynamics of Halide Perovskite. Advanced Functional Materials 2023, 33
(17)
https://doi.org/10.1002/adfm.202214180
- Shubhangi Bhardwaj, Ashutosh Mohanty, Ranjan Das, Pallavi Singh, Ankit Singh, Dipankar Das Sarma, Sushobhan Avasthi. Dielectric Properties of Acetamidinium Substituted Methylammonium Lead Iodide Perovskite. 2022, 1-5. https://doi.org/10.1109/ICEE56203.2022.10118156
- Fumin Guo, Jian Wang, Yu Li, Shanshan Yu, Xiuwen Xu, Xin Cai, Yueping Fang, Lionel Vayssieres, Makhsud I. Saidaminov, Shihe Yang. Postripening Fabrication and Self‐Driven Narrowband Photoresponse of Large‐Grain, Phase‐Pure CsPbBr
3
Films. Solar RRL 2022, 6
(12)
https://doi.org/10.1002/solr.202200828
- Mohd Warish, Khursheed Ahmad Parrey, Gaurav Jamwal, Asad Niazi. Structural, optical and dielectric properties of low temperature assisted grown crystals of CH3NH3Pb1-xCdxBr3. Materials Chemistry and Physics 2022, 292 , 126852. https://doi.org/10.1016/j.matchemphys.2022.126852
- Chiara Dionigi, Meriem Goudjil, Giampiero Ruani, Luca Bindi. The Effect of Short Chain Carboxylic Acids as Additives on the Crystallization of Methylammonium Lead Triiodide (MAPI). Inorganics 2022, 10
(11)
, 201. https://doi.org/10.3390/inorganics10110201
- Daniel L. Gau, Daniel Ramírez, Fernando Iikawa, Gonzalo Riveros, Patricia Díaz, Javier Verdugo, Gerard Núñez, Susy Lizama, Pamela Lazo, Enrique A. Dalchiele, Lidia Contreras, Jesús Idigoras, Juan Anta, Ricardo E. Marotti. Photophysical and Photoelectrochemical Properties of CsPbBr
3
Films Grown by Electrochemically Assisted Deposition. ChemPhysChem 2022, 23
(19)
https://doi.org/10.1002/cphc.202200286
- Philippe Basset, Stephen Paul Beeby, Chris Bowen, Zheng Jun Chew, Ahmad Delbani, R. D. Ishara G. Dharmasena, Bhaskar Dudem, Feng Ru Fan, Dimitri Galayko, Hengyu Guo, Jianhua Hao, Yuchen Hou, Chenguo Hu, Qingshen Jing, Young Hoon Jung, Sumanta Kumar Karan, Sohini Kar-Narayan, Miso Kim, Sang-Woo Kim, Yang Kuang, Keon Jae Lee, Jialu Li, Zhaoling Li, Yin Long, Shashank Priya, Xianjie Pu, Tingwen Ruan, S. Ravi P. Silva, Hee Seung Wang, Kai Wang, Xudong Wang, Zhong Lin Wang, Wenzhuo Wu, Wei Xu, Hemin Zhang, Yan Zhang, Meiling Zhu. Roadmap on nanogenerators and piezotronics. APL Materials 2022, 10
(10)
https://doi.org/10.1063/5.0085850
- Moon Ryul Sihn, Jihoon Choi. Alignment of Metal Halide Perovskite Nanowires and Their Application in Photodetectors. Korean Journal of Materials Research 2022, 32
(6)
, 307-312. https://doi.org/10.3740/MRSK.2022.32.6.307
- Mohamed Ben Bechir, Abdelkareem Almeshal, Mohamed Houcine Dhaou. Interpretation of the giant dielectric constant in the single crystal of the CH3NH3PbBr3 perovskite. Materials Research Bulletin 2022, 149 , 111723. https://doi.org/10.1016/j.materresbull.2021.111723
- Congying Liu, Zhenwei Wang, Wenqi Xiong, Hongxia Zhong, Shengjun Yuan. Effect of vertical strain and in-plane biaxial strain on type-II MoSi2N4/Cs3Bi2I9 van der Waals heterostructure. Journal of Applied Physics 2022, 131
(16)
https://doi.org/10.1063/5.0080224
- Peng Zeng, Xinjian Ren, Linfeng Wei, Haifeng Zhao, Xiaochun Liu, Xinyang Zhang, Yanmin Xu, Lihe Yan, Klaus Boldt, Trevor A. Smith, Mingzhen Liu. Control of Hot Carrier Relaxation in CsPbBr
3
Nanocrystals Using Damping Ligands. Angewandte Chemie 2022, 134
(15)
https://doi.org/10.1002/ange.202111443
- Peng Zeng, Xinjian Ren, Linfeng Wei, Haifeng Zhao, Xiaochun Liu, Xinyang Zhang, Yanmin Xu, Lihe Yan, Klaus Boldt, Trevor A. Smith, Mingzhen Liu. Control of Hot Carrier Relaxation in CsPbBr
3
Nanocrystals Using Damping Ligands. Angewandte Chemie International Edition 2022, 61
(15)
https://doi.org/10.1002/anie.202111443
- Artavazd Kirakosyan, Moon Ryul Sihn, Min-Gi Jeon, Rezaul M.D. Kabir, Jihoon Choi. Self-aligned CH3NH3PbBr3 perovskite nanowires via dielectrophoresis for gas sensing applications. Applied Materials Today 2022, 26 , 101307. https://doi.org/10.1016/j.apmt.2021.101307
- Claudiu M. Iaru, Annalisa Brodu, Niels J. J. van Hoof, Stan E. T. ter Huurne, Jonathan Buhot, Federico Montanarella, Sophia Buhbut, Peter C. M. Christianen, Daniël Vanmaekelbergh, Celso de Mello Donega, Jaime Gòmez Rivas, Paul M. Koenraad, Andrei Yu. Silov. Fröhlich interaction dominated by a single phonon mode in CsPbBr3. Nature Communications 2021, 12
(1)
https://doi.org/10.1038/s41467-021-26192-0
- Maciej Ptak, Adam Sieradzki, Mantas Šimėnas, Mirosław Maczka. Molecular spectroscopy of hybrid organic–inorganic perovskites and related compounds. Coordination Chemistry Reviews 2021, 448 , 214180. https://doi.org/10.1016/j.ccr.2021.214180
- F.B. Minussi, S.P. Reis, E.B. Araújo. Effects of frequency, temperature, and dc bias electric field on the dielectric properties of methylammonium lead iodide from the perspective of a relaxor-like ferroelectric. Acta Materialia 2021, 219 , 117235. https://doi.org/10.1016/j.actamat.2021.117235
- Ting Xiao, Jie Zhao, Peng Sun, Peng Li, Yaokang Zhang, Ni Zhao, Zhiwei Ren, Gang Li, Zhifeng Huang, Zijian Zheng. Sensitive, High‐Speed, and Broadband Perovskite Photodetectors with Built‐In TiO
2
Metalenses. Small 2021, 17
(41)
https://doi.org/10.1002/smll.202102694
- Clayton J. Dahlman, Dominik J. Kubicki, G. N. Manjunatha Reddy. Interfaces in metal halide perovskites probed by solid-state NMR spectroscopy. Journal of Materials Chemistry A 2021, 9
(35)
, 19206-19244. https://doi.org/10.1039/D1TA03572J
- N. Suresh Kumar, K. Chandra Babu Naidu. A review on perovskite solar cells (PSCs), materials and applications. Journal of Materiomics 2021, 7
(5)
, 940-956. https://doi.org/10.1016/j.jmat.2021.04.002
- Sarah Deumel, Albert van Breemen, Gerwin Gelinck, Bart Peeters, Joris Maas, Roy Verbeek, Santhosh Shanmugam, Hylke Akkerman, Eric Meulenkamp, Judith E. Huerdler, Manognya Acharya, Marisé García-Batlle, Osbel Almora, Antonio Guerrero, Germà Garcia-Belmonte, Wolfgang Heiss, Oliver Schmidt, Sandro F. Tedde. High-sensitivity high-resolution X-ray imaging with soft-sintered metal halide perovskites. Nature Electronics 2021, 4
(9)
, 681-688. https://doi.org/10.1038/s41928-021-00644-3
- Boyuan Huang, Zhenghao Liu, Changwei Wu, Yuan Zhang, Jinjin Zhao, Xiao Wang, Jiangyu Li. Polar or nonpolar? That is not the question for perovskite solar cells. National Science Review 2021, 8
(8)
https://doi.org/10.1093/nsr/nwab094
- Roxana Patru, Hamidreza Khassaf, Iuliana Pasuk, Mihaela Botea, Lucian Trupina, Constantin-Paul Ganea, Lucian Pintilie, Ioana Pintilie. Tetragonal–Cubic Phase Transition and Low-Field Dielectric Properties of CH3NH3PbI3 Crystals. Materials 2021, 14
(15)
, 4215. https://doi.org/10.3390/ma14154215
- Eve M. Mozur, James R. Neilson. Cation Dynamics in Hybrid Halide Perovskites. Annual Review of Materials Research 2021, 51
(1)
, 269-291. https://doi.org/10.1146/annurev-matsci-080819-012808
- Shrreya Krishnamurthy, Padmini Pandey, Jagjit Kaur, Sudip Chakraborty, Pabitra K Nayak, Aditya Sadhanala, Satishchandra Ogale. Organic–inorganic hybrid and inorganic halide perovskites: structural and chemical engineering, interfaces and optoelectronic properties. Journal of Physics D: Applied Physics 2021, 54
(13)
, 133002. https://doi.org/10.1088/1361-6463/abd0ad
- Supriya Ghosh, Bapi Pradhan, Yiyue Zhang, Johan Hofkens, Khadga J. Karki, Arnulf Materny. Nature of the different emissive states and strong exciton–phonon couplings in quasi-two-dimensional perovskites derived from phase-modulated two-photon micro-photoluminescence spectroscopy. Physical Chemistry Chemical Physics 2021, 23
(6)
, 3983-3992. https://doi.org/10.1039/D0CP05538G
- Alessandra Geddo Lehmann, Francesco Congiu, Daniela Marongiu, Andrea Mura, Alessio Filippetti, Alessandro Mattoni, Michele Saba, Guido Pegna, Valerio Sarritzu, Francesco Quochi, Giovanni Bongiovanni. Long-lived electrets and lack of ferroelectricity in methylammonium lead bromide CH
3
NH
3
PbBr
3
ferroelastic single crystals. Physical Chemistry Chemical Physics 2021, 23
(5)
, 3233-3245. https://doi.org/10.1039/D0CP05918H
- Jin-Wook Lee, Seongrok Seo, Pronoy Nandi, Hyun Suk Jung, Nam-Gyu Park, Hyunjung Shin. Dynamic structural property of organic-inorganic metal halide perovskite. iScience 2021, 24
(1)
, 101959. https://doi.org/10.1016/j.isci.2020.101959
- Pronoy Nandi, Dinesh Topwal, Nam-Gyu Park, Hyunjung Shin. Organic-inorganic hybrid lead halides as absorbers in perovskite solar cells: a debate on ferroelectricity. Journal of Physics D: Applied Physics 2020, 53
(49)
, 493002. https://doi.org/10.1088/1361-6463/abb047
- Prasun Banerjee, N. Suresh Kumar, Kadiyala Chandra Babu Naidu, A. Franco, Ravinder Dachepalli. Stability of 2D and 3D Perovskites Due to Inhibition of Light-Induced Decomposition. Journal of Electronic Materials 2020, 49
(12)
, 7072-7084. https://doi.org/10.1007/s11664-020-08435-w
- Bumseop Kim, Jeongwoo Kim, Noejung Park. First-principles identification of the charge-shifting mechanism and ferroelectricity in hybrid halide perovskites. Scientific Reports 2020, 10
(1)
https://doi.org/10.1038/s41598-020-76742-7
- Marisé García‐Batlle, Oriane Baussens, Smaïl Amari, Julien Zaccaro, Eric Gros‐Daillon, Jean‐Marie Verilhac, Antonio Guerrero, Germà Garcia‐Belmonte. Moving Ions Vary Electronic Conductivity in Lead Bromide Perovskite Single Crystals through Dynamic Doping. Advanced Electronic Materials 2020, 6
(10)
https://doi.org/10.1002/aelm.202000485
- Ali Sehpar Shikoh, Sanghyun Paek, Alexander Y. Polyakov, Nikolai B. Smirnov, Ivan V. Shchemerov, Danila S. Saranin, Sergey I. Didenko, Zubair Ahmad, Farid Touati, Mohammad Khaja Nazeeruddin. Assessing mobile ions contributions to admittance spectra and current-voltage characteristics of 3D and 2D/3D perovskite solar cells. Solar Energy Materials and Solar Cells 2020, 215 , 110670. https://doi.org/10.1016/j.solmat.2020.110670
- Malladi Srikanth, Mailde S. Ozório, Juarez L. F. Da Silva. Optical and dielectric properties of lead perovskite and iodoplumbate complexes: an
ab initio
study. Physical Chemistry Chemical Physics 2020, 22
(33)
, 18423-18434. https://doi.org/10.1039/D0CP03512B
- Ali Sehpar Shikoh, A. Y. Polyakov, N. B. Smirnov, I. V. Shchemerov, D. S. Saranin, S. I. Didenko, D. V. Kuznetsov, A. Agresti, S. Pescetelli, A. Di Carlo. Ion Dynamics in Single and Multi-Cation Perovskite. ECS Journal of Solid State Science and Technology 2020, 9
(6)
, 065015. https://doi.org/10.1149/2162-8777/abaaf3
- Anusit Thongnum, Udomsilp Pinsook. Polaron transport in hybrid CH
3
NH
3
PbI
3
perovskite thin films. Nanoscale 2020, 12
(26)
, 14112-14119. https://doi.org/10.1039/D0NR03432K
- F. B. Minussi, S. P. Reis, E. B. Araújo. An unusual frequency dispersion of the dielectric permittivity maxima at temperatures around the tetragonal–cubic phase transition of methylammonium lead iodide. Journal of Applied Physics 2020, 127
(24)
https://doi.org/10.1063/5.0012428
Article Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.
Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.
The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated.
Recommended Articles
Abstract
Figure 1
Figure 1. Dielectric constant, ε′, versus temperature for selected frequencies measured on MAPbBr3 (symbol and solid lines) and CsPbBr3 (dashed lines) (a) and MAPbI3 (b). The insets in (a) and (b) show the fit to the experimental data of the dielectric constant vs temperature in the tetragonal phase of MAPbBr3 and MAPbI3, respectively.
Figure 2
Figure 2. Molecular polarization Pmol(t) in the 64 and 216 unit cell, called 4-cell and 6-cell, respectively, at 300 K starting from an unpolarized-random (R) structure and from a polarized-aligned (A) starting structure. Average values for independent-random dipoles for the same system size are indicated by the dashed lines.
Figure 3
Figure 3. Spectra of the second harmonic generated at 900 nm with an incident 1800 nm laser measured on (a) MAPbI3 and urea with a pump power of 2.84 mW, (b) MAPbBr3 with a pump power of 2.62 mW, and (c) CsPbBr3 with a pump power of 2.60 mW at a few selected delay times indicated in the legend. It can be seen that all of the spectra at different delay times overlap.
Figure 4
Figure 4. SHG efficiency of MAPbI3, MAPbBr3, and CsPbBr3 with respect to urea plotted against the delay time between the 400 nm pump and 1800 nm probe. The dashed lines drawn for reference in each panel represent the average SHG efficiency calculated for spectra before the arrival of the pump pulse. The pump powers were 2.84, 2.62, and 2.60 mW for MAPbI3, MAPbBr3, and CsPbBr3, respectively.
References
This article references 64 other publications.
- 1Bi, D.; Tress, W.; Dar, M. I.; Gao, P.; Luo, J.; Renevier, C.; Schenk, K.; Abate, A.; Giordano, F.; Correa Baena, J.-P. Efficient luminescent solar cells based on tailored mixed-cation perovskites Sci. Adv. 2016, 2, e1501170 DOI: 10.1126/sciadv.1501170There is no corresponding record for this reference.
- 2McMeekin, D. P.; Sadoughi, G.; Rehman, W.; Eperon, G. E.; Saliba, M.; Hörantner, M. T.; Haghighirad, A.; Sakai, N.; Korte, L.; Rech, B. A mixed-cation lead mixed-halide perovskite absorber for tandem solar cells Science 2016, 351, 151– 155 DOI: 10.1126/science.aad58452https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhvV2itg%253D%253D&md5=7d7494e92975225df9b665c13c82f46cA mixed-cation lead mixed-halide perovskite absorber for tandem solar cellsMcMeekin, David P.; Sadoughi, Golnaz; Rehman, Waqaas; Eperon, Giles E.; Saliba, Michael; Hoerantner, Maximilian T.; Haghighirad, Amir; Sakai, Nobuya; Korte, Lars; Rech, Bernd; Johnston, Michael B.; Herz, Laura M.; Snaith, Henry J.Science (Washington, DC, United States) (2016), 351 (6269), 151-155CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)Metal halide perovskite photovoltaic cells could potentially boost the efficiency of com. silicon photovoltaic modules from ∼20 toward 30% when used in tandem architectures. An optimum perovskite cell optical band gap of ∼1.75 eV (eV) can be achieved by varying halide compn., but to date, such materials have had poor photostability and thermal stability. Here we present a highly cryst. and compositionally photostable material, [HC(NH2)2]0.83Cs0.17Pb(I0.6Br0.4)3, with an optical band gap of ∼1.74 eV, and we fabricated perovskite cells that reached open-circuit voltages of 1.2 V and power conversion efficiency of over 17% on small areas and 14.7% on 0.715 cm2 cells. By combining these perovskite cells with a 19%-efficient silicon cell, we demonstrated the feasibility of achieving >25%-efficient four-terminal tandem cells.
- 3Saliba, M.; Matsui, T.; Seo, J.-Y.; Domanski, K.; Correa-Baena, J.-P.; Nazeeruddin, M. K.; Zakeeruddin, S. M.; Tress, W.; Abate, A.; Hagfeldt, A. Cesium-containing triple cation perovskite solar cells: improved stability, reproducibility and high efficiency Energy Environ. Sci. 2016, 9, 1989– 1997 DOI: 10.1039/C5EE03874J3https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XksVSjt78%253D&md5=4a099536bf11a3c84c6e6e792d192664Cesium-containing triple cation perovskite solar cells: improved stability, reproducibility and high efficiencySaliba, Michael; Matsui, Taisuke; Seo, Ji-Youn; Domanski, Konrad; Correa-Baena, Juan-Pablo; Nazeeruddin, Mohammad Khaja; Zakeeruddin, Shaik M.; Tress, Wolfgang; Abate, Antonio; Hagfeldt, Anders; Gratzel, MichaelEnergy & Environmental Science (2016), 9 (6), 1989-1997CODEN: EESNBY; ISSN:1754-5706. (Royal Society of Chemistry)Today's best perovskite solar cells use a mixt. of formamidinium and methylammonium as the monovalent cations. With the addn. of inorg. cesium, the resulting triple cation perovskite compns. are thermally more stable, contain less phase impurities and are less sensitive to processing conditions. This enables more reproducible device performances to reach a stabilized power output of 21.1% and ∼18% after 250 h under operational conditions. These properties are key for the industrialization of perovskite photovoltaics.
- 4Yoon, H.; Kang, S. M.; Lee, J.-K.; Choi, M. Hysteresis-free low-temperature-processed planar perovskite solar cells with 19.1% efficiency Energy Environ. Sci. 2016, 9, 2262– 2266 DOI: 10.1039/C6EE01037G4https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XovFWisbs%253D&md5=01ce9e7d07653b09a26a71b42ae9c7d9Hysteresis-free low-temperature-processed planar perovskite solar cells with 19.1% efficiencyYoon, Heetae; Kang, Seong Min; Lee, Jong-Kwon; Choi, MansooEnergy & Environmental Science (2016), 9 (7), 2262-2266CODEN: EESNBY; ISSN:1754-5706. (Royal Society of Chemistry)Hysteresis-free, highly efficient and stable perovskite solar cells processed at low temps. are strongly demanded to realize flexible or perovskite-based tandem solar cells. Here, we report a hysteresis-free planar CH3NH3PbI3 perovskite solar cell with a power conversion efficiency of 19.1% using a room-temp. vacuum-processed C60 electron transport layer (ETL) without the hole blocking layer. By optimizing the thickness of the C60 layer, the highly homogeneous, uniform, and dense ETL with a thickness of 35 nm is found to not only passivate the grain boundaries and surfaces of the perovskite layer, but also enhance charge transport properties. Thus, the C60 layer deposited on perovskites eliminates the photocurrent hysteresis and improves the cell efficiency. Also, compared to the device adopting the C60 and bathocuproine (BCP) combination, the one with the C60 layer without the BCP layer shows better performance due to enhanced electron extn. properties. Furthermore, for the first time, we have demonstrated a hysteresis-free flexible perovskite solar cell using the C60 ETL on a polyethylene naphthalate (PEN) substrate with 16.0% efficiency.
- 5Baikie, T.; Fang, Y.; Kadro, J. M.; Schreyer, M.; Wei, F.; Mhaisalkar, S. G.; Graetzel, M.; White, T. J. Synthesis and crystal chemistry of the hybrid perovskite (CH3NH3)PbI3 for solid-state sensitised solar cell applications J. Mater. Chem. A 2013, 1, 5628– 5641 DOI: 10.1039/c3ta10518k5https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXmtF2isb8%253D&md5=aa26f1e37df912912faed0c8b37f757bSynthesis and crystal chemistry of the hybrid perovskite (CH3NH3)PbI3 for solid-state sensitised solar cell applicationsBaikie, Tom; Fang, Yanan; Kadro, Jeannette M.; Schreyer, Martin; Wei, Fengxia; Mhaisalkar, Subodh G.; Graetzel, Michael; White, Tim J.Journal of Materials Chemistry A: Materials for Energy and Sustainability (2013), 1 (18), 5628-5641CODEN: JMCAET; ISSN:2050-7496. (Royal Society of Chemistry)The hybrid org.-inorg. perovskite (CH3NH3)PbI3 may find application in next generation solid-state sensitized solar cells. Although this material and related perovskites were discovered many decades ago, questions remain concerning their diverse structural chem. and unusual properties. The article presents a review of previous work and provides a detailed description of the prepn., structural characterization and phys. characteristics of (CH3NH3)PbI3. The phase changes exhibited by (CH3NH3)PbI3 have been probed using variable temp. powder and single crystal x-ray diffraction, combined with differential scanning calorimetry, thermogravimetric anal. and phase contrast transmission electron microscopy. The optical band gap for (CH3NH3)PbI3 detd. by UV-visible spectroscopy was compared to values obtained from d.-of-state simulation of the electronic band structure.
- 6Butler, K. T.; Frost, J. M.; Walsh, A. Band alignment of the hybrid halide perovskites CH3NH3PbCl3, CH3NH3PbBr3 and CH3NH3PbI3 Mater. Horiz. 2015, 2, 228– 231 DOI: 10.1039/C4MH00174E6https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvVWlsr7M&md5=19cab0870a720f0bc1e1cf33dc529240Band alignment of the hybrid halide perovskites CH3NH3PbCl3, CH3NH3PbBr3 and CH3NH3PbI3Butler, Keith T.; Frost, Jarvist M.; Walsh, AronMaterials Horizons (2015), 2 (2), 228-231CODEN: MHAOBM; ISSN:2051-6355. (Royal Society of Chemistry)Org.-inorg. halide perovskites efficiently convert sunlight to electricity in solar cells. The choice of halide (Cl, Br or I) can be used to chem. tune the spectral response of the materials and the positions of the valence and conduction bands (i.e. the ionization potential and electron affinity). Here the band offsets of the methylammonium lead halides are reported, including relativistic corrections and using the Pb 1s core level as a ref. state. The binding energy of the valence band decreases monotonically down the series, primarily due to the change from 3p to 4p to 5p valence orbitals of the halide. Type I band alignments are predicted, which implies that Br and Cl secondary phases in CH3NH3PbI3 thin-films would act as barriers to charge transport in photovoltaic devices.
- 7Bokdam, M.; Sander, T.; Stroppa, A.; Picozzi, S.; Sarma, D. D.; Franchini, C.; Kresse, G. Role of polar phonons in the photo excited state of metal halide perovskites Sci. Rep. 2016, 6, 28618 DOI: 10.1038/srep286187https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhtFSisbrF&md5=fef5a7deb5e0c07aaa0eb7a7ba952c8bRole of Polar Phonons in the Photo Excited State of Metal Halide PerovskitesBokdam, Menno; Sander, Tobias; Stroppa, Alessandro; Picozzi, Silvia; Sarma, D. D.; Franchini, Cesare; Kresse, GeorgScientific Reports (2016), 6 (), 28618CODEN: SRCEC3; ISSN:2045-2322. (Nature Publishing Group)The development of high efficiency perovskite solar cells has sparked a multitude of measurements on the optical properties of these materials. For the most studied methylammonium(MA)PbI3 perovskite, a large range (6-55 meV) of exciton binding energies has been reported by various expts. The existence of excitons at room temp. is unclear. For the MAPbX3 perovskites we report on relativistic Bethe-Salpeter Equation calcns. (GW-BSE). This method is capable to directly calc. excitonic properties from first-principles. At low temps. it predicts exciton binding energies in agreement with the reported 'large' values. For MAPbI3, phonon modes present in this frequency range have a negligible contribution to the ionic screening. By calcg. the polarization in time from finite temp. mol. dynamics, we show that at room temp. this does not change. We therefore exclude ionic screening as an explanation for the exptl. obsd. redn. of the exciton binding energy at room temp. and argue in favor of the formation of polarons.
- 8Poglitsch, A.; Weber, D. Dynamic disorder in methylammoniumtrihalogenoplumbates (II) observed by millimeter-wave spectroscopy J. Chem. Phys. 1987, 87, 6373– 6378 DOI: 10.1063/1.4534678https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL1cXht1arsLo%253D&md5=f528e1c73c9b3e007ec5d7ca47650b39Dynamic disorder in methylammonium trihaloplumbates(II) observed by millimeter-wave spectroscopyPoglitsch, A.; Weber, D.Journal of Chemical Physics (1987), 87 (11), 6373-8CODEN: JCPSA6; ISSN:0021-9606.The temp.-dependent structure of cryst. methylammonium trihaloplumbates(II) CH3NH3+PbX3- (X = Cl, Br, I) as detd. by x-ray diffraction, was compared with measurements of the temp.-dependent complex permittivity at frequencies of 50-150 GHz. The dielec. measurements reveal a ps relaxation process which corresponds to a dynamic disorder of the methylammonium group in the high-temp. phases of the trihaloplumbates.
- 9Swainson, I. P.; Hammond, R. P.; Soullière, C.; Knop, O.; Massa, W. Phase transitions in the perovskite methylammonium lead bromide, CH3ND3PbBr3 J. Solid State Chem. 2003, 176, 97– 104 DOI: 10.1016/S0022-4596(03)00352-99https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXovVWntro%253D&md5=949bb0a19b3c2ed6aedda78931bef434Phase transitions in the perovskite methylammonium lead bromide, CH3ND3PbBr3Swainson, I. P.; Hammond, R. P.; Soulliere, C.; Knop, O.; Massa, W.Journal of Solid State Chemistry (2003), 176 (1), 97-104CODEN: JSSCBI; ISSN:0022-4596. (Elsevier Science)The structure of phase IV of methylammonium lead bromide, CH3ND3PbBr3, is shown from Rietveld refinement of neutron powder diffraction data to be centrosym., with space group Pnma: Z = 4; a 7.9434(4), b 11.8499(5), c 8.5918(4) Å at 11 K; Rwp = 2.34% Rp = 1.81%. This corresponds to one of the pure tilt transitions, a-b+a-, commonly obsd. in perovskites. Addnl. distortions not required by pure tilting are found in the PbBr6 octahedra, and apparently the structure optimizes the H bonding between the methylammonium cation and the framework. It is likely that the lowest temp. phase of the corresponding iodide also has this structure. The structure is compared to the available data for that of other Pnma perovskites. A brief comparison to the higher temp. phases in which the methylammonium ion is disordered is given.
- 10Chi, L.; Swainson, I.; Cranswick, L.; Her, J.-H.; Stephens, P.; Knop, O. The ordered phase of methylammonium lead chloride CH3ND3PbCl3 J. Solid State Chem. 2005, 178, 1376– 1385 DOI: 10.1016/j.jssc.2004.12.03710https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXjvV2gs7Y%253D&md5=f164b5177ad39cf04c8b642db25495e4The ordered phase of methylammonium lead chloride CH3ND3PbCl3Chi, Lisheng; Swainson, Ian; Cranswick, Lachlan; Her, Jae-Hyuk; Stephens, Peter; Knop, OsvaldJournal of Solid State Chemistry (2005), 178 (5), 1376-1385CODEN: JSSCBI; ISSN:0022-4596. (Elsevier)The perovskite-structured compd. methylammonium lead chloride orders into a low-temp. phase of space group Pnma, in which at 80 K each of the orthorhombic axes a 11.1747(2), b 11.3552(1) and c 11.2820(1) Å is doubled with respect to the room temp. disordered cubic phase (a 5.669 Å). Crystallog. data and at. coordinates are given. The structure was solved by ab initio methods using the programs EXPO and FOX. This unusual cell basis for space group Pnma is not that of a std. tilt system. This phase, in which the methylammonium ions, are ordered shows distorted octahedra. The octahedra possess a bond angle variance of 60.663°2 and a quadratic elongation of 1.018, and are more distorted than those in the ordered phase of methylammonium lead bromide. There is also an alternating long and short Pb-Cl bond along a, due to an off-center displacement of Pb within the octahedron. Probably the most rigid unit is actually the methylammonium cation, rather than the PbCl6 octahedra, in agreement with existing spectroscopic data.
- 11G, S.; Mahale, P.; Kore, B. P.; Mukherjee, S.; Pavan, M. S.; De, C.; Ghara, S.; Sundaresan, A.; Pandey, A.; Guru Row, T. N. Is CH3NH3PbI3 polar? J. Phys. Chem. Lett. 2016, 7, 2412– 2419 DOI: 10.1021/acs.jpclett.6b0080311https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XpsFGqu7g%253D&md5=62073baaa71baa8a86762806be86aa9eIs CH3NH3PbI3 Polar?G, Sharada; Mahale, Pratibha; Kore, Bhushan P.; Mukherjee, Somdutta; Pavan, Mysore S.; De, Chandan; Ghara, Somnath; Sundaresan, A.; Pandey, Anshu; Guru Row, Tayur N.; Sarma, D. D.Journal of Physical Chemistry Letters (2016), 7 (13), 2412-2419CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)In view of the continued controversy concerning the polar/nonpolar nature of the hybrid perovskite system, CH3NH3PbI3, we report the first investigation of a time-resolved pump-probe measurement of the second harmonic generation efficiency as well as using its more traditional form as a sensitive probe of the absence/presence of the center of inversion in the system both in its excited and ground states, resp. Our results clearly show that SHG efficiency, if nonzero, is below the limit of detection, strongly indicative of a nonpolar or centrosym. structure. Our results on the same samples, based on temp. dependent single crystal X-ray diffraction and P-E loop measurements, are entirely consistent with the above conclusion of a centrosym. structure for this compd. in all three phases, namely the high temp. cubic phase, the intermediate temp. tetragonal phase and the low temp. orthorhombic phase. It is important to note that all our exptl. probes are vol. averaging and performed on bulk materials, suggesting that basic material properties of CH3NH3PbI3 are consistent with a centrosym., nonpolar structure.
- 12Wasylishen, R. E.; Knop, O.; Macdonald, J. B. Cation rotation in methylammonium lead halides Solid State Commun. 1985, 56, 581– 582 DOI: 10.1016/0038-1098(85)90959-712https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL2MXmt1CrsrY%253D&md5=7dbbb3236b992be7213270ccf60bc36eCation rotation in methylammonium lead halidesWasylishen, R. E.; Knop, Osvald; Macdonald, J. B.Solid State Communications (1985), 56 (7), 581-2CODEN: SSCOA4; ISSN:0038-1098.2H and 14N NMR spectra of the simple perovskites MeNH3PbX3 (X = Cl, Br, I) reveal the existence of several phases. In the high-temp. phase I the long spin-lattice relaxation times T1 of both nuclei and the absence of quadrupole splitting indicate extremely rapid overall reorientation of the C-N axis of the cation in a potential of cubic symmetry. In phase II of the bromide and iodide, both T1 and the small quadrupole splitting show unusual variation with temp. In the lowest-temp. phase, rotations of the C-N axis are restricted.
- 13Knop, O.; Wasylishen, R. E.; White, M. A.; Cameron, T. S.; Oort, M. J. M. V. Alkylammonium lead halides. Part 2. CH3NH3PbX3 (X = Cl, Br, I) perovskites: cuboctahedral halide cages with isotropic cation reorientation Can. J. Chem. 1990, 68, 412– 422 DOI: 10.1139/v90-06313https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3cXit1Ojtrg%253D&md5=5c25c736c86cf3e06a11daee3d671a41Alkylammonium lead halides. Part 2. CH3NH3PbX3 (X = chlorine, bromine, iodine) perovskites: cuboctahedral halide cages with isotropic cation reorientationKnop, Osvald; Wasylishen, Roderick E.; White, Mary Anne; Cameron, T. Stanley; Van Oort, Michiel J. M.Canadian Journal of Chemistry (1990), 68 (3), 412-22CODEN: CJCHAG; ISSN:0008-4042.MeNH3PbCl3 (I), MeNH3PbBr3 (II), and MeNH3PbI3 (III) were investigated by single-crystal x-ray diffraction, 2H and 14N NMR, adiabatic calorimetry, and other methods. I has transitions at 171.5 and 177.4 K, II at 148.4, 154.2, and 235.1 K, and III at 162.7 and 326.6 K. The resp. entropies of transition (J K-1 mol-1) are 11.0 and 5.1 for I; 8.7, 3.4, and 5.3 for II; and 16.1 and 1.9 for III. The highest-temp. phase, phase I, of each halide is cubic (Pm3m) perovskite type. The cation in phase I of I and II could not be localized in the electron d. maps; the thermal motion of the halogen atom is highly anisotropic. The ln T1(2H) vs. T-1 plots (N-deuterated samples as well as CD3NH3PbCl3) show significant departures from linearity: the temp. variation of T1(2H) in phase II of II and III can be represented by functions of the type ln T1(H) = k0 - k2T-2, which give adequate anal. representations of T1(2H) and T1(14N) in phase I as well. On cooling, phase II of II and III exhibit small quadrupole splittings QS(2H), which can be represented to a high degree of correlation by QS(2H) = k(Ttr - T)n, i.e. they appear to exhibit crit. behavior with respect to T. The 14N NMR results indicate that the C-N bond in phase I reorients in an isotropic potential at a rate approaching that of the freely rotating methylammonium ion. Below phase I this motion takes place in an increasingly anisotropic potential in phase II of II and III and is essentially arrested in phase II of I and phase III of II and III. The temp. dependence of the activation energy Ea for the cation reorientation and other aspects of the non-Arrhenius behavior are discussed, and the MeNH3PbX3 perovskites are compared with the corresponding (MeNH3)2TeX6 halides, utilizing preliminary 2H NMR results on (CD3ND3)2TeBr6. The elec. cond., between 0 and 95°, of III increases with temp. and exhibits no discontinuity at Ttr = 326.6 K; the activation energy for the conduction process is estd. as ∼0.4 eV.
- 14Onoda-Yamamuro, N.; Matsuo, T.; Suga, H. Calorimetric and IR spectroscopic studies of phase transitions in methylammonium trihalogenoplumbates (II) J. Phys. Chem. Solids 1990, 51, 1383– 1395 DOI: 10.1016/0022-3697(90)90021-714https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3MXhtFahsL4%253D&md5=e87ac8ccd0e391890852451c44f992d9Calorimetric and IR spectroscopic studies of phase transitions in methylammonium trihaloplumbates(II)Onoda-Yamamuro, Noriko; Matsuo, Takasuke; Suga, HiroshiJournal of Physics and Chemistry of Solids (1990), 51 (12), 1383-95CODEN: JPCSAW; ISSN:0022-3697.Heat capacities of CH3NH3PbX3(X = Cl, Br, I) were measured at 13-300 K (365 K for the I). Two anomalies were found in the Cl and the I, and 3 in the Br. All the phase transitions were of the 1st order, although the highest temp. transitions in the Br and the I were close to 2nd order. Their temps. and entropies are given.
- 15Bakulin, A. A.; Selig, O.; Bakker, H. J.; Rezus, Y. L. A.; Müller, C.; Glaser, T.; Lovrincic, R.; Sun, Z.; Chen, Z.; Walsh, A. Real-time observation of organic cation reorientation in methylammonium lead iodide perovskites J. Phys. Chem. Lett. 2015, 6, 3663– 3669 DOI: 10.1021/acs.jpclett.5b0155515https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsVeqtr%252FN&md5=e2b0e1618dc96a9c16d80cf6fbf2c66bReal-Time Observation of Organic Cation Reorientation in Methylammonium Lead Iodide PerovskitesBakulin, Artem A.; Selig, Oleg; Bakker, Huib J.; Rezus, Yves L. A.; Mueller, Christian; Glaser, Tobias; Lovrincic, Robert; Sun, Zhenhua; Chen, Zhuoying; Walsh, Aron; Frost, Jarvist M.; Jansen, Thomas L. C.Journal of Physical Chemistry Letters (2015), 6 (18), 3663-3669CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)The introduction of a mobile and polarized org. moiety as a cation in 3D Pb-iodide perovskites brings fascinating optoelectronic properties to these materials. The extent and the time scales of the orientational mobility of the org. cation and the mol. mechanism behind its motion remain unclear, with different exptl. and computational approaches providing very different qual. and quant. description of the mol. dynamics. Ultrafast 2D vibrational spectroscopy of methylammonium (MA) Pb iodide was used to directly resolve the rotation of the org. cations within the MAPbI3 lattice. The results reveal 2 characteristic time consts. of motion. Using ab initio mol. dynamics simulations, the authors identify these as a fast (∼300 fs) wobbling-in-a-cone motion around the crystal axis and a relatively slow (∼3 ps) jump-like reorientation of the mol. dipole with respect to the iodide lattice. The obsd. dynamics are essential for understanding the electronic properties of perovskite materials.
- 16Chen, T.; Foley, B. J.; Ipek, B.; Tyagi, M.; Copley, J. R. D.; Brown, C. M.; Choi, J. J.; Lee, S.-H. Rotational dynamics of organic cations in the CH3NH3PbI3 perovskite Phys. Chem. Chem. Phys. 2015, 17, 31278– 31286 DOI: 10.1039/C5CP05348J16https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhslamsL3M&md5=189c259f9616321de62cf9d18afedd21Rotational dynamics of organic cations in the CH3NH3PbI3 perovskiteChen, Tianran; Foley, Benjamin J.; Ipek, Bahar; Tyagi, Madhusudan; Copley, John R. D.; Brown, Craig M.; Choi, Joshua J.; Lee, Seung-HunPhysical Chemistry Chemical Physics (2015), 17 (46), 31278-31286CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Methylammonium lead iodide (CH3NH3PbI3) based solar cells have shown impressive power conversion efficiencies of above 20%. However, the microscopic mechanism of the high photovoltaic performance is yet to be fully understood. Particularly, the dynamics of CH3NH3+ cations and their impact on relevant processes such as charge recombination and exciton dissocn. are still poorly understood. Here, using elastic and quasi-elastic neutron scattering techniques and group theor. anal., we studied rotational modes of the CH3NH3+ cation in CH3NH3PbI3. Our results show that, in the cubic (T > 327 K) and tetragonal (165 K < T < 327 K) phases, the CH3NH3+ ions exhibit four-fold rotational symmetry of the C-N axis (C4) along with three-fold rotation around the C-N axis (C3), while in the orthorhombic phase (T < 165 K) only C3 rotation is present. At around room temp., the characteristic relaxation times for the C4 rotation are found to be τC4 ≈ 5 ps while for the C3 rotation τC3 ≈ 1 ps. The T-dependent rotational relaxation times were fitted with Arrhenius equations to obtain activation energies. Our data show a close correlation between the C4 rotational mode and the temp. dependent dielec. permittivity. Our findings on the rotational dynamics of CH3NH3+ and the assocd. dipole have important implications for understanding the low exciton binding energy and a slow charge recombination rate in CH3NH3PbI3 which are directly relevant for the high solar cell performance.
- 17Leguy, A. M. A.; Frost, J. M.; McMahon, A. P.; Sakai, V. G.; Kockelmann, W.; Law, C.; Li, X.; Foglia, F.; Walsh, A.; O’Regan, B. C. The dynamics of methylammonium ions in hybrid organic-inorganic perovskite solar cells Nat. Commun. 2015, 6, 7124 DOI: 10.1038/ncomms812417https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2MfosFGmsQ%253D%253D&md5=31e6a49b8b65b776f79b1c53e28b6e3aThe dynamics of methylammonium ions in hybrid organic-inorganic perovskite solar cellsLeguy Aurelien M A; McMahon Andrew P; Nelson Jenny; Barnes Piers R F; Frost Jarvist Moore; Walsh Aron; Sakai Victoria Garcia; Kochelmann W; Law ChunHung; Li Xiaoe; O'Regan Brian C; Foglia Fabrizia; Cabral Joao TNature communications (2015), 6 (), 7124 ISSN:.Methylammonium lead iodide perovskite can make high-efficiency solar cells, which also show an unexplained photocurrent hysteresis dependent on the device-poling history. Here we report quasielastic neutron scattering measurements showing that dipolar CH3NH3(+) ions reorientate between the faces, corners or edges of the pseudo-cubic lattice cages in CH3NH3PbI3 crystals with a room temperature residence time of ∼14 ps. Free rotation, π-flips and ionic diffusion are ruled out within a 1-200-ps time window. Monte Carlo simulations of interacting CH3NH3(+) dipoles realigning within a 3D lattice suggest that the scattering measurements may be explained by the stabilization of CH3NH3(+) in either antiferroelectric or ferroelectric domains. Collective realignment of CH3NH3(+) to screen a device's built-in potential could reduce photovoltaic performance. However, we estimate the timescale for a domain wall to traverse a typical device to be ∼0.1-1 ms, faster than most observed hysteresis.
- 18Létoublon, A.; Paofai, S.; Rufflé, B.; Bourges, P.; Hehlen, B.; Michel, T.; Ecolivet, C.; Durand, O.; Cordier, S.; Katan, C. Elastic constants, optical phonons, and molecular relaxations in the high temperature plastic phase of the CH3NH3PbBr3 hybrid perovskite J. Phys. Chem. Lett. 2016, 7, 3776– 3784 DOI: 10.1021/acs.jpclett.6b0170918https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsV2gsb7M&md5=bd5c2cf5261f2fc474a3c70833042cc1Elastic Constants, Optical Phonons, and Molecular Relaxations in the High Temperature Plastic Phase of the CH3NH3PbBr3 Hybrid PerovskiteLetoublon, Antoine; Paofai, Serge; Ruffle, Benoit; Bourges, Philippe; Hehlen, Bernard; Michel, Thierry; Ecolivet, Claude; Durand, Olivier; Cordier, Stephane; Katan, Claudine; Even, JackyJournal of Physical Chemistry Letters (2016), 7 (19), 3776-3784CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)Low frequency dynamics was studied in a MeNH3PbBr3 hybrid perovskite single crystal by using 4 different spectroscopy techniques: coherent inelastic neutron, Raman and Brillouin scatterings, and ultrasound measurements. Sound velocities were measured over 5 decades in energy to yield the complete set of elastic consts. in a hybrid halide perovskite crystal in the pseudocubic plastic phase. The C44 shear elastic const. is very small, leading to a particularly low resistance to shear stress. Brillouin scattering was used to study the relaxation dynamics of methylammonium cations and to evidence translation-rotation coupling assocd. with the cubic to tetragonal phase transition at Tc ≈ 230 K. Low frequency and highly damped optical phonons obsd. using both Raman and inelastic neutron <18 meV, do not present softening close to Tc. The crit. dynamics at Tc ≈ 230 K is compatible with an order-disorder character, dominated by relaxational motions of the mols.
- 19Selig, O.; Sadhanala, A.; Müller, C.; Lovrincic, R.; Chen, Z.; Rezus, Y. L. A.; Frost, J. M.; Jansen, T. L. C.; Bakulin, A. A. Organic cation rotation and immobilization in pure and mixed methylammonium lead-halide perovskites J. Am. Chem. Soc. 2017, 139, 4068– 4074 DOI: 10.1021/jacs.6b1223919https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXjsVCmu74%253D&md5=4ae35418cf8381183ff66c1c44965df9Organic Cation Rotation and Immobilization in Pure and Mixed Methylammonium Lead-Halide PerovskitesSelig, Oleg; Sadhanala, Aditya; Mueller, Christian; Lovrincic, Robert; Chen, Zhuoying; Rezus, Yves L. A.; Frost, Jarvist M.; Jansen, Thomas L. C.; Bakulin, Artem A.Journal of the American Chemical Society (2017), 139 (11), 4068-4074CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)Three-dimensional lead-halide perovskites have attracted a lot of attention due to their ability to combine soln. processing with outstanding optoelectronic properties. Despite their soft ionic nature these materials demonstrate a surprisingly low level of electronic disorder resulting in sharp band edges and narrow distributions of the electronic energies. Understanding how structural and dynamic disorder impacts the optoelectronic properties of these perovskites is important for many applications. Here the authors combine ultrafast two-dimensional vibrational spectroscopy and mol. dynamics simulations to study the dynamics of the org. methylammonium (MA) cation orientation in a range of pure and mixed trihalide perovskite materials. For pure MAPbX3 (X = I, Br, Cl) perovskite films, the cation dynamics accelerate with decreasing size of the halide atom. This acceleration is surprising given the expected strengthening of the hydrogen bonds between the MA and the smaller halide anions, but can be explained by the increase in the polarizability with the size of halide. Much slower dynamics, up to partial immobilization of the org. cation, are obsd. in the mixed MAPb(ClxBr1-x)3 and MAPb(BrxI1-x)3 alloys, which the authors assoc. with symmetry breaking within the perovskite unit cell. The obsd. dynamics are essential for understanding the effects of structural and dynamical disorder in perovskite-based optoelectronic systems.
- 20Onoda-Yamamuro, N.; Matsuo, T.; Suga, H. Dielectric study of CH3NH3PbX3 (X = Cl, Br, I) J. Phys. Chem. Solids 1992, 53, 935– 939 DOI: 10.1016/0022-3697(92)90121-S20https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK38XkvVWnu7k%253D&md5=ffb7e052bff5035c77595ef8e0307414Dielectric study of CH3NH3PbX3 (X = Cl, Br, I)Onoda-Yamamuro, Noriko; Matsuo, Takasuke; Suga, HiroshiJournal of Physics and Chemistry of Solids (1992), 53 (7), 935-9CODEN: JPCSAW; ISSN:0022-3697.Complex dielec. permittivities of CH3NH3PbX3 (X = Cl, Br, I) were measured at frequencies between 20 Hz and 1 MHz and at 20-300 K (15-350 K for the iodide). Discontinuities or a sharp bend of the real part of the dielec. permittivity occurred at the phase transitions, except at the tetragonal (I4/mcm)-cubic phase transition where the permittivity showed no apparent change. The dielec. behaviors in the cubic and tetragonal (I4/mcm) phases are described well by a modified Kirkwood-Froehlich equation. Dielec. dispersions were found in the orthorhombic phase of CH3NH3PbBr3 and CH3NH3PbI3 at 30-120 K.
- 21Quarti, C.; Grancini, G.; Mosconi, E.; Bruno, P.; Ball, J. M.; Lee, M. M.; Snaith, H. J.; Petrozza, A.; Angelis, F. D. The Raman spectrum of the CH3NH3PbI3 hybrid perovskite: interplay of theory and experiment J. Phys. Chem. Lett. 2014, 5, 279– 284 DOI: 10.1021/jz402589q21https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhvFyrtr7P&md5=dca655cda936ae4e6fddcb2e4ce862e5The Raman Spectrum of the CH3NH3PbI3 Hybrid Perovskite: Interplay of Theory and ExperimentQuarti, Claudio; Grancini, Giulia; Mosconi, Edoardo; Bruno, Paola; Ball, James M.; Lee, Michael M.; Snaith, Henry J.; Petrozza, Annamaria; Angelis, Filippo DeJournal of Physical Chemistry Letters (2014), 5 (2), 279-284CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)The authors report the low-frequency resonant Raman spectrum of methylammonium Pb-iodide, a prototypical perovskite for solar cells applications, on mesoporous Al2O3. The measured spectrum assignment is assisted by DFT simulations of the Raman spectra of suitable periodic and model systems. The bands at 62 and 94 cm-1 are assigned resp. to the bending and to the stretching of the Pb-I bonds, and are thus diagnostic modes of the inorg. cage. The authors also assign the librations of the org. cations at 119 and 154 cm-1. The broad, unstructured 200-400 cm-1 features are assigned to the torsional mode of the methylammonium cations, which the authors propose as a marker of the orientational disorder of the material. Study provides the basis to interpret the Raman spectra of organohalide perovskites, which may allow 1 to further understand the properties of this important class of materials in relation to their full exploitation in solar cells.
- 22Brivio, F.; Frost, J. M.; Skelton, J. M.; Jackson, A. J.; Weber, O. J.; Weller, M. T.; Goñi, A. R.; Leguy, A. M. A.; Barnes, P. R. F.; Walsh, A. Lattice dynamics and vibrational spectra of the orthorhombic, tetragonal, and cubic phases of methylammonium lead iodide Phys. Rev. B: Condens. Matter Mater. Phys. 2015, 92, 144308 DOI: 10.1103/PhysRevB.92.14430822https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XktlOruro%253D&md5=d032de453e4ee67d539fe3c2501b99d8Lattice dynamics and vibrational spectra of the orthorhombic, tetragonal, and cubic phases of methylammonium lead iodideBrivio, Federico; Frost, Jarvist M.; Skelton, Jonathan M.; Jackson, Adam J.; Weber, Oliver J.; Weller, Mark T.; Goni, Alejandro R.; Leguy, Aurelien M. A.; Barnes, Piers R. F.; Walsh, AronPhysical Review B: Condensed Matter and Materials Physics (2015), 92 (14), 144308/1-144308/8CODEN: PRBMDO; ISSN:1098-0121. (American Physical Society)The hybrid halide perovskite CH3NH3PbI3 exhibits a complex structural behavior, with successive transitions between orthorhombic, tetragonal, and cubic polymorphs around 165 and 327 K. Herein we report first-principles lattice dynamics (phonon spectrum) for each phase of CH3NH3PbI3. The equil. structures compare well to solns. of temp.-dependent powder neutron diffraction. By following the normal modes, we calc. IR and Raman intensities of the vibrations, and compare them to the measurement of a single crystal where the Raman laser is controlled to avoid degrdn. of the sample. Despite a clear sepn. in energy between low-frequency modes assocd. with the inorg. (PbI3-)n network and high-frequency modes of the org. CH3NH3+ cation, significant coupling between them is found, which emphasizes the interplay between mol. orientation and the corner-sharing octahedral networks in the structural transformations. Soft modes are found at the boundary of the Brillouin zone of the cubic phase, consistent with displacive instabilities and anharmonicity involving tilting of the PbI6 octahedra around room temp.
- 23Stoumpos, C. C.; Malliakas, C. D.; Kanatzidis, M. G. Semiconducting tin and lead iodide perovskites with organic cations: phase transitions, high mobilities, and near-infrared photoluminescent properties Inorg. Chem. 2013, 52, 9019– 9038 DOI: 10.1021/ic401215x23https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtVGqsL3N&md5=94c35d645dcd9770b4097d0bd440269bSemiconducting Tin and Lead Iodide Perovskites with Organic Cations: Phase Transitions, High Mobilities, and Near-Infrared Photoluminescent PropertiesStoumpos, Constantinos C.; Malliakas, Christos D.; Kanatzidis, Mercouri G.Inorganic Chemistry (2013), 52 (15), 9019-9038CODEN: INOCAJ; ISSN:0020-1669. (American Chemical Society)A broad org.-inorg. series of hybrid metal iodide perovskites AMI3, where A is the methylammonium (MeNH3+) or formamidinium (HC(NH2)2+) cation and M is Sn (1 and 2) or Pb (3 and 4) are reported. The compds. were prepd. through a variety of synthetic approaches, and the nature of the resulting materials is discussed in terms of their thermal stability and optical and electronic properties. The chem. and phys. properties of these materials strongly depend on the prepn. method. Single crystal x-ray diffraction anal. of 1-4 classifies the compds. in the perovskite structural family. Structural phase transitions were obsd. and studied by temp.-dependent single crystal x-ray diffraction in the 100-400 K range. The charge transport properties of the materials are discussed in conjunction with diffuse reflectance studies in the mid-IR region that display characteristic absorption features. Temp.-dependent studies show a strong dependence of the resistivity as a function of the crystal structure. Optical absorption measurements indicate that 1-4 behave as direct-gap semiconductors with energy band gaps distributed at 1.25-1.75 eV. The compds. exhibit an intense near-IR luminescence (PL) emission in the 700-1000 nm range (1.1-1.7 eV) at room temp. Solid solns. between the Sn and Pb compds. are readily accessible throughout the compn. range. The optical properties such as energy band gap, emission intensity, and wavelength can be readily controlled for the isostructural series of solid solns. MeNH3Sn1-xPbxI3 (5). The charge transport type in these materials was characterized by Seebeck coeff. and Hall-effect measurements. The compds. behave as p- or n-type semiconductors depending on the prepn. method. The samples with the lowest carrier concn. are prepd. from soln. and are n-type; p-type samples can be obtained through solid state reactions exposed in air in a controllable manner. In the case of Sn compds., there is a facile tendency toward oxidn. which causes the materials to be doped with Sn4+ and thus behave as p-type semiconductors displaying metal-like cond. The compds. appear to possess very high estd. electron and hole mobilities that exceed 2000 cm2/(V s) and 300 cm2/(V s), resp., as shown in the case of MeNH3SnI3 (1). The authors also compare the properties of the title hybrid materials with those of the all-inorg. CsSnI3 and CsPbI3 prepd. using identical synthetic methods.
- 24Frost, J. M.; Butler, K. T.; Brivio, F.; Hendon, C. H.; van Schilfgaarde, M.; Walsh, A. Atomistic origins of high-performance in hybrid halide perovskite solar cells Nano Lett. 2014, 14, 2584– 2590 DOI: 10.1021/nl500390f24https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXltF2nu7Y%253D&md5=3b52f943bd4e397862fd02953c1e11faAtomistic Origins of High-Performance in Hybrid Halide Perovskite Solar CellsFrost, Jarvist M.; Butler, Keith T.; Brivio, Federico; Hendon, Christopher H.; van Schilfgaarde, Mark; Walsh, AronNano Letters (2014), 14 (5), 2584-2590CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)The performance of organometallic perovskite solar cells has rapidly surpassed that of both conventional dye-sensitized and org. photovoltaics. High-power conversion efficiency can be realized in both mesoporous and thin-film device architectures. The authors address the origin of this success in the context of the materials chem. and physics of the bulk perovskite as described by electronic structure calcns. In addn. to the basic optoelectronic properties essential for an efficient photovoltaic device (spectrally suitable band gap, high optical absorption, low carrier effective masses), the materials are structurally and compositionally flexible. As the authors show, hybrid perovskites exhibit spontaneous elec. polarization; the authors also suggest ways in which this can be tuned through judicious choice of the org. cation. The presence of ferroelec. domains will result in internal junctions that may aid sepn. of photoexcited electron and hole pairs, and redn. of recombination through segregation of charge carriers. The combination of high dielec. const. and low effective mass promotes both Wannier-Mott exciton sepn. and effective ionization of donor and acceptor defects. The photoferroic effect could be exploited in nanostructured films to generate a higher open circuit voltage and may contribute to the current-voltage hysteresis obsd. in perovskite solar cells.
- 25Kutes, Y.; Ye, L.; Zhou, Y.; Pang, S.; Huey, B. D.; Padture, N. P. Direct observation of ferroelectric domains in solution-processed CH3NH3PbI3 perovskite thin films J. Phys. Chem. Lett. 2014, 5, 3335– 3339 DOI: 10.1021/jz501697b25https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsFCjsbrO&md5=88f2a0705f393c936074acd540b2f34bDirect Observation of Ferroelectric Domains in Solution-Processed CH3NH3PbI3 Perovskite Thin FilmsKutes, Yasemin; Ye, Linghan; Zhou, Yuanyuan; Pang, Shuping; Huey, Bryan D.; Padture, Nitin P.Journal of Physical Chemistry Letters (2014), 5 (19), 3335-3339CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)A new generation of solid-state photovoltaics is being made possible by the use of organometal-trihalide perovskite materials. While some of these materials are expected to be ferroelec., almost nothing is known about their ferroelec. properties exptl. Using piezoforce microscopy (PFM), here we show unambiguously, for the first time, the presence of ferroelec. domains in high-quality β-CH3NH3PbI3 perovskite thin films that have been synthesized using a new soln.-processing method. The size of the ferroelec. domains is found to be about the size of the grains (∼100 nm). We also present evidence for the reversible switching of the ferroelec. domains by poling with DC biases. This suggests the importance of further PFM investigations into the local ferroelec. behavior of hybrid perovskites, in particular in situ photoeffects. Such investigations could contribute toward the basic understanding of photovoltaic mechanisms in perovskite-based solar cells, which is essential for the further enhancement of the performance of these promising photovoltaics.
- 26Wei, J.; Zhao, Y.; Li, H.; Li, G.; Pan, J.; Xu, D.; Zhao, Q.; Yu, D. Hysteresis analysis based on the ferroelectric effect in hybrid perovskite solar cells J. Phys. Chem. Lett. 2014, 5, 3937– 3945 DOI: 10.1021/jz502111u26https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvVWgu7zL&md5=4ea652347f2a38bbe75e25dde860542cHysteresis Analysis Based on the Ferroelectric Effect in Hybrid Perovskite Solar CellsWei, Jing; Zhao, Yicheng; Li, Heng; Li, Guobao; Pan, Jinlong; Xu, Dongsheng; Zhao, Qing; Yu, DapengJournal of Physical Chemistry Letters (2014), 5 (21), 3937-3945CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)The power conversion efficiency (PCE) of CH3NH3PbX3 (X = I, Br, Cl) perovskite solar cells was developed rapidly from 6.5 to 18% within 3 years. However, the anomalous hysteresis found in I-V measurements can cause an inaccurate estn. of the efficiency. The authors attribute the phenomena to the ferroelec. effect and build a model based on the ferroelec. diode to explain it. The ferroelec. effect of CH3NH3PbI3-xClx is strongly suggested by characterization methods and the E-P (elec. field-polarization) loop. The hysteresis in I-V curves greatly depends on the scan range as well as the velocity, which is well explained by the ferroelec. diode model. Also the current signals show exponential decay in ∼10 s under prolonged stepwise measurements, and the anomalous hysteresis disappears using these stabilized current values. The exptl. results accord well with the model based on ferroelec. properties and prove that prolonged stepwise measurement is an effective way to evaluate the real efficiency of perovskite solar cells. Most importantly, this work provides a meaningful perspective that the ferroelec. effect (if it really exists) should be paid special attention in the optimization of perovskite solar cells.
- 27Quarti, C.; Mosconi, E.; De Angelis, F. Interplay of orientational order and electronic structure in methylammonium lead iodide: implications for solar cell operation Chem. Mater. 2014, 26, 6557– 6569 DOI: 10.1021/cm503204627https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhsl2ht77E&md5=fbfd6eb91c91e82068bdb7213ba8cc86Interplay of Orientational Order and Electronic Structure in Methylammonium Lead Iodide: Implications for Solar CellQuarti, Claudio; Mosconi, Edoardo; De Angelis, FilippoChemistry of Materials (2014), 26 (22), 6557-6569CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)The ab initio electronic structure and Car-Parrinello mol. dynamics simulations are reported for several structural models of the prototype MAPbI3 perovskite for solar cells applications. Both configurations having a preferred orientation are considered of the MA cations, giving rise to a net dipole alignment, and configurations with an isotropic distribution of the MA cations, resp. representative of polar (ferroelec.) and apolar (antiferroelec.) structures. The calcns. demonstrate the preferred stability of a set of polar structures over apolar ones, with an energy difference within 0.1 eV and a conversion barrier within 0.2 eV per unit cell (four MAPbI3), thus possibly accessible at room temp. Ferroelec.-like orientations lead to a quasi I4cm structure for the inorg. component, characterized by lack of inversion symmetry, while the antiferroelec.-like orientations are assocd. to a quasi I4/mcm structure. Ab initio mol. dynamics simulations on the polar structures show no mol. rotations in the investigated time-scale, while several MA rotations are obsd. in the same time scale for the considered apolar structure, which is thus characterized by a higher disorder. The I4cm and I4/mcm types of structure have markedly different band structures, despite showing a relatively small band gap variation. Simulations carried out on finite surface slabs demonstrate that a net orientation of the MA cations gives rise to a strong bending in the valence and conduction bands, which could definitely assist charge sepn. and reduce carrier recombination, provided one is able to effectively stabilize polar compared to apolar structures. The results could contribute an important step toward an in-depth comprehension of the basic properties of organohalide perovskites, assisting a further optimization of their photovoltaic response.
- 28Chen, H.-W.; Sakai, N.; Ikegami, M.; Miyasaka, T. Emergence of hysteresis and transient ferroelectric response in organo-lead halide perovskite solar cells J. Phys. Chem. Lett. 2015, 6, 164– 169 DOI: 10.1021/jz502429u28https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXitFehsL3K&md5=2d086a807969d24950871b8ea2f3262aEmergence of Hysteresis and Transient Ferroelectric Response in Organo-Lead Halide Perovskite Solar CellsChen, Hsin-Wei; Sakai, Nobuya; Ikegami, Masashi; Miyasaka, TsutomuJournal of Physical Chemistry Letters (2015), 6 (1), 164-169CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)Although there was rapid progress in the efficiency of perovskite-based solar cells, hysteresis in the current-voltage performance is not yet completely understood. Owing to its complex structure, it is not easy to attribute the hysteretic behavior to any one of different components, such as the bulk of the perovskite or different heterojunction interfaces. Among organo-lead halide perovskites, methylammonium lead iodide perovskite (CH3NH3PbI3) is known to have a ferroelec. property. The present study reveals a strong correlation between transient ferroelec. polarization of CH3NH3PbI3 induced by an external bias in the dark and hysteresis enhancement in photovoltaic characteristics. The authors' results demonstrate that the reverse bias poling (-0.3 to -1.1 V) of CH3NH3PbI3 photovoltaic layers prior to the photocurrent-voltage measurement generates stronger hysteresis whose extent changes significantly by the cell architecture. The phenomenon is interpreted as the effect of remanent polarization in the perovskite film on the photocurrent, which is most enhanced in planar perovskite structures without mesoporous scaffolds.
- 29Zheng, F.; Takenaka, H.; Wang, F.; Koocher, N. Z.; Rappe, A. M. First-principles calculation of the bulk photovoltaic effect in CH3NH3PbI3 and CH3NH3PbI3–xClx J. Phys. Chem. Lett. 2015, 6, 31– 37 DOI: 10.1021/jz502109e29https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhvFOhtr7E&md5=45844907636fe1a492ccc168915d0193First-Principles Calculation of the Bulk Photovoltaic Effect in CH3NH3PbI3 and CH3NH3PbI3-xClxZheng, Fan; Takenaka, Hiroyuki; Wang, Fenggong; Koocher, Nathan Z.; Rappe, Andrew M.Journal of Physical Chemistry Letters (2015), 6 (1), 31-37CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)Hybrid halide perovskites exhibit nearly 20% power conversion efficiency, but the origin of their high efficiency is still unknown. Here, we compute the shift current, a dominant mechanism of the bulk photovoltaic (PV) effect for ferroelec. photovoltaics, in CH3NH3PbI3 and CH3NH3PbI3-xClx from first-principles. We find that these materials give approx. three times larger shift current PV response to near-IR and visible light than the prototypical ferroelec. photovoltaic BiFeO3. The mol. orientations of CH3NH+3 can strongly affect the corresponding PbI3 inorg. frame so as to alter the magnitude of the shift current response. Specifically, configurations with dipole moments aligned in parallel distort the inorg. PbI3 frame more significantly than configurations with near-net-zero dipole, yielding a larger shift current response. Furthermore, we explore the effect of Cl substitution on shift current and find that Cl substitution at the equatorial site induces a larger response than does substitution at the apical site.
- 30Chen, B.; Shi, J.; Zheng, X.; Zhou, Y.; Zhu, K.; Priya, S. Ferroelectric solar cells based on inorganic-organic hybrid perovskites J. Mater. Chem. A 2015, 3, 7699– 7705 DOI: 10.1039/C5TA01325A30https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXjvF2ktLs%253D&md5=be7d1c8eac955bb64b4e1bb5f249e438Ferroelectric solar cells based on inorganic-organic hybrid perovskitesChen, Bo; Shi, Jian; Zheng, Xiaojia; Zhou, Yuan; Zhu, Kai; Priya, ShashankJournal of Materials Chemistry A: Materials for Energy and Sustainability (2015), 3 (15), 7699-7705CODEN: JMCAET; ISSN:2050-7496. (Royal Society of Chemistry)Ferroelec. solar cells based on ferroelec. oxides have attracted significant attention owing to many unique advantages, such as the switchable photocurrent and photovoltage, and the above bandgap open circuit voltages. However, the small photocurrent densities of the typical ferroelec. solar cells greatly limit their photovoltaic performance. In this report, the polarization switching properties of inorg.-org. hybrid perovskites are revealed exptl. and ferroelec. solar cells based on the hybrid perovskites are developed. Hybrid perovskite methylammonium lead trihalide (MAPbX3) thin films exhibited 180° domain phase switching and polarization hysteresis loops. Ferroelec. solar cells based on the mixed halide MAPbI3-xClx thin film demonstrate a power conversion efficiency of 6.7% and the ferroelec. solar cells display switchable photovoltaic effects. This work provides an alternative but exhilarating soln. for high-performance ferroelec. solar cells beyond inorg. ferroelec. oxides.
- 31Dang, Y.; Liu, Y.; Sun, Y.; Yuan, D.; Liu, X.; Lu, W.; Liu, G.; Xia, H.; Tao, X. Bulk crystal growth of hybrid perovskite material CH3NH3PbI3 CrystEngComm 2015, 17, 665– 670 DOI: 10.1039/C4CE02106A31https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXitVSit7zO&md5=25b523421d793fb45e82b8d424e10929Bulk crystal growth of hybrid perovskite material CH3NH3PbI3Dang, Yangyang; Liu, Yang; Sun, Youxuan; Yuan, Dongsheng; Liu, Xiaolong; Lu, Weiqun; Liu, Guangfeng; Xia, Haibing; Tao, XutangCrystEngComm (2015), 17 (3), 665-670CODEN: CRECF4; ISSN:1466-8033. (Royal Society of Chemistry)Org.-inorg. hybrid perovskite materials have been receiving considerable attention due to their promising applications in many optoelectronic fields. However, some of the fundamental properties of perovskite materials are still disputed, because most of them are derived from a thin-film state. To comprehend the intrinsic characteristics in a single crystal, herein we report, for the first time, the bulk crystal growth of CH3NH3PbI3. Single crystals of tetragonal CH3NH3PbI3 with dimensions of 10 mm × 10 mm × 8 mm were grown by a temp.-lowering method in HI soln. Studies in to the refinement and orientations of the CH3NH3PbI3 single crystal structure were conducted based on a high quality crystal. The absorption edge of a CH3NH3PbI3 single crystal was located at about 836 nm, indicating that the band gap of CH3NH3PbI3 is approx. 1.48 eV, which is close to the theor. results and smaller than those derived from polycryst. and thin-films. CH3NH3PbI3 crystal exhibits a relatively wide absorption (from 250 nm to 800 nm) and a relatively good thermal stability.
- 32Kim, H.-S.; Kim, S. K.; Kim, B. J.; Shin, K.-S.; Gupta, M. K.; Jung, H. S.; Kim, S.-W.; Park, N.-G. Ferroelectric polarization in CH3NH3PbI3 perovskite J. Phys. Chem. Lett. 2015, 6, 1729– 1735 DOI: 10.1021/acs.jpclett.5b0069532https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXmvVynuro%253D&md5=34bd8f150addf70e3a27a2a2859e9647Ferroelectric Polarization in CH3NH3PbI3 PerovskiteKim, Hui-Seon; Kim, Sung Kyun; Kim, Byeong Jo; Shin, Kyung-Sik; Gupta, Manoj Kumar; Jung, Hyun Suk; Kim, Sang-Woo; Park, Nam-GyuJournal of Physical Chemistry Letters (2015), 6 (9), 1729-1735CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)We report on ferroelec. polarization behavior in CH3NH3PbI3 perovskite in the dark and under illumination. Perovskite crystals with three different sizes of 700, 400, and 100 nm were prepd. for piezoresponse force microscopy (PFM) measurements. PFM results confirmed the formation of spontaneous polarization in CH3NH3PbI3 in the absence of elec. field, where the size dependency to polarization was not significant. Whereas the photoinduced stimulation was not significant without an external elec. field, the stimulated polarization by poling was further enhanced under illumination. The retention of ferroelec. polarization was also obsd. after removal of the elec. field, in which larger crystals showed longer retention behavior compared to the smaller sized one. Addnl., we suggest the effect of perovskite crystal size (morphol.) on charge collection at the interface of the ferroelec. material even though insignificant size dependency in elec. polarization was obsd.
- 33Liu, S.; Zheng, F.; Koocher, N. Z.; Takenaka, H.; Wang, F.; Rappe, A. M. Ferroelectric domain wall induced band gap reduction and charge separation in organometal halide perovskites J. Phys. Chem. Lett. 2015, 6, 693– 699 DOI: 10.1021/jz502666j33https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtlyqsrc%253D&md5=67a184d53926d79ffbafd47f7b416686Ferroelectric domain wall induced band gap reduction and charge separation in organometal halide perovskitesLiu, Shi; Zheng, Fan; Koocher, Nathan Z.; Takenaka, Hiroyuki; Wang, Fenggong; Rappe, Andrew M.Journal of Physical Chemistry Letters (2015), 6 (4), 693-699CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)Organometal halide perovskites have been intensely studied in the past 5 years, inspired by their certified high photovoltaic power conversion efficiency. Some of these materials are room-temp. ferroelecs. The presence of switchable ferroelec. domains in methylammonium lead triiodide, CH3NH3PbI3, has recently been obsd. via piezoresponse force microscopy. Here, we focus on the structural and electronic properties of ferroelec. domain walls in CH3NH3PbX3 (X = Cl, Br, I). We find that organometal halide perovskites can form both charged and uncharged domain walls due to the flexible orientational order of the org. mols. The electronic band gaps for domain structures possessing 180 and 90° walls are estd. with d. functional theory. It is found that the presence of charged domain walls will significantly reduce the band gap by 20-40%, while the presence of uncharged domain walls has no substantial impact on the band gap. We demonstrate that charged domain walls can serve as segregated channels for the motions of charge carriers. These results highlight the importance of ferroelec. domain walls in hybrid perovskites for photovoltaic applications and suggest a possible avenue for device optimization through domain patterning.
- 34Rashkeev, S. N.; El-Mellouhi, F.; Kais, S.; Alharbi, F. H. Domain walls conductivity in hybrid organometallic perovskites and their essential role in CH3NH3PbI3 solar cell high performance Sci. Rep. 2015, 5, 11467 DOI: 10.1038/srep1146734https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtFyhsbnP&md5=97d09bc93586801654e60ebff355ec33Domain Walls Conductivity in Hybrid Organometallic Perovskites and Their Essential Role in CH3NH3PbI3 Solar Cell High PerformanceRashkeev, Sergey N.; El-Mellouhi, Fedwa; Kais, Sabre; Alharbi, Fahhad H.Scientific Reports (2015), 5 (), 11467CODEN: SRCEC3; ISSN:2045-2322. (Nature Publishing Group)The past several years has witnessed a surge of interest in organometallic trihalide perovskites, which are at the heart of the new generation of solid-state solar cells. Here, we calcd. the static cond. of charged domain walls in n- and p- doped organometallic uniaxial ferroelec. semiconductor perovskite CH3NH3PbI3 using the Landau-Ginzburg-Devonshire (LGD) theory. We find that due to the charge carrier accumulation, the static cond. may drastically increase at the domain wall by 3 - 4 orders of magnitude in comparison with cond. through the bulk of the material. Also, a two-dimensional degenerated gas of highly mobile charge carriers could be formed at the wall. The high values of cond. at domain walls and interfaces explain high efficiency in organometallic soln.-processed perovskite films which contains lots of different point and extended defects. These results could suggest new routes to enhance the performance of this promising class of novel photovoltaic materials.
- 35Stroppa, A.; Quarti, C.; De Angelis, F.; Picozzi, S. Ferroelectric polarization of CH3NH3PbI3: a detailed study based on density functional theory and symmetry mode analysis J. Phys. Chem. Lett. 2015, 6, 2223– 2231 DOI: 10.1021/acs.jpclett.5b0054235https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXovFKqtLY%253D&md5=be712c52c0a6929b5374bf318651d59cFerroelectric Polarization of CH3NH3PbI3: A Detailed Study Based on Density Functional Theory and Symmetry Mode AnalysisStroppa, Alessandro; Quarti, Claudio; De Angelis, Filippo; Picozzi, SilviaJournal of Physical Chemistry Letters (2015), 6 (12), 2223-2231CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)Ferroelectricity in halide perovskites currently represents a crucial issue, as it may have an important role for the enhancement of solar cells efficiency. Simulations of ferroelec. properties based on d. functional theory are conceptually more demanding compared with conventional inorg. ferroelecs. due to the presence of both org. and inorg. components in the same compd. Here the authors present a detailed study focused on the prototypical CH3NH3PbI3 perovskite. By using d. functional theory combined with symmetry mode anal., the authors disentangle the contributions of the methylammonium cations and the role of the inorg. framework, therefore suggesting possible routes to enhance the polarization in this compd. The authors' est. of the polarization for the tetragonal phase at low temp. is ∼4.42 μC/cm2, which is substantially lower than that of traditional perovskite oxides.
- 36Seol, D.; Han, G. S.; Bae, C.; Shin, H.; Jung, H. S.; Kim, Y. Screening effect on photovoltaic performance in ferroelectric CH3NH3PbI3 perovskite thin films J. Mater. Chem. A 2015, 3, 20352– 20358 DOI: 10.1039/C5TA06190C36https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsVegsbbO&md5=7075589378b89e823bb0afe24e64338bScreening effect on photovoltaic performance in ferroelectric CH3NH3PbI3 perovskite thin filmsSeol, Daehee; Han, Gill Sang; Bae, Changdeuck; Shin, Hyunjung; Jung, Hyun Suk; Kim, YunseokJournal of Materials Chemistry A: Materials for Energy and Sustainability (2015), 3 (40), 20352-20358CODEN: JMCAET; ISSN:2050-7496. (Royal Society of Chemistry)Org. and inorg. hybrid materials of CH3NH3PbX3 with a perovskite crystal structure have been conceived as emerging light absorbing materials for high efficiency photovoltaic devices. Here, we demonstrate the screening effect of polarization states on charge redistribution related to the photovoltaic performance of ferroelec. CH3NH3PbI3 thin films using at. force microscopy. We show the interplay between polarization and injected charges to have significant effects on charge transfer which potentially influences photovoltaic performance. The obtained results reveal that the direction and the amt. of charge transfer can be influenced by the screening of polarization states at the interface. These results could deliver fundamental information regarding the influence of ferroelectricity on CH3NH3PbX3 solar cells.
- 37Zhao, P.; Xu, J.; Ma, C.; Ren, W.; Wang, L.; Bian, L.; Chang, A. Spontaneous polarization behaviors in hybrid halide perovskite film Scr. Mater. 2015, 102, 51– 54 DOI: 10.1016/j.scriptamat.2015.01.03037https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXjvFCis7s%253D&md5=6441cb0eb746d824ff843b3d07e2e9caSpontaneous polarization behaviors in hybrid halide perovskite filmZhao, Pengjun; Xu, Jinbao; Ma, Chao; Ren, Wei; Wang, Lei; Bian, Liang; Chang, AiminScripta Materialia (2015), 102 (), 51-54CODEN: SCMAF7; ISSN:1359-6462. (Elsevier Ltd.)Spontaneous polarization behaviors of hybrid perovskite CH3NH3PbI3 film were confirmed by in situ PFM and spectroscopic ellipsometry. The film exhibits uniform spontaneous polarization and ferroelec. domain inversion performance. The fitted dielec. consts. spectra agree well with the calcd. ones. We attribute the spontaneous polarization behaviors of hybrid perovskite to lone pair electrons, and its outstanding photovoltaic performance partially originates from spontaneous polarization and plasma resonance. This report will facilitate understanding of the instinct phys. essence of hybrid perovskite solar cells.
- 38Hermes, I. M.; Bretschneider, S. A.; Bergmann, V. W.; Li, D.; Klasen, A.; Mars, J.; Tremel, W.; Laquai, F.; Butt, H.-J.; Mezger, M. Ferroelastic fingerprints in methylammonium lead iodide perovskite J. Phys. Chem. C 2016, 120, 5724– 5731 DOI: 10.1021/acs.jpcc.5b1146938https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XisVyhtL4%253D&md5=c975b568cd875558162b5ce24baaf007Ferroelastic Fingerprints in Methylammonium Lead Iodide PerovskiteHermes, Ilka M.; Bretschneider, Simon A.; Bergmann, Victor W.; Li, Dan; Klasen, Alexander; Mars, Julian; Tremel, Wolfgang; Laquai, Frederic; Butt, Hans-Juergen; Mezger, Markus; Berger, Ruediger; Rodriguez, Brian J.; Weber, Stefan A. L.Journal of Physical Chemistry C (2016), 120 (10), 5724-5731CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Methylammonium lead iodide (MAPbI3) perovskite shows an outstanding performance in photovoltaic devices. However, certain material properties, esp. the possible ferroic behavior, remain unclear. We obsd. distinct nanoscale periodic domains in the piezoresponse of MAPbI3(Cl) grains. The structure and the orientation of these striped domains indicate ferroelasticity as their origin. By correlating vertical and lateral piezoresponse force microscopy expts. performed at different sample orientations with X-ray diffraction, the preferred domain orientation is suggested to be the a1-a2-phase. The observation of these ferroelastic fingerprints appears to strongly depend on the film texture and thus the prepn. route. The ferroelastic twin domains could form due to the introduction of strain during the cubic-tetragonal phase transition.
- 39Wang, P.; Zhao, J.; Wei, L.; Zhu, Q.; Xie, S.; Liu, J.; Meng, X.; Li, J. Photo-induced ferroelectric switching in perovskite CH3NH3PbI3 films Nanoscale 2017, 9, 3806– 3817 DOI: 10.1039/C6NR09310H39https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhs1KisL0%253D&md5=9cd141c5886e632a4573e4158725d322Photo-induced ferroelectric switching in perovskite CH3NH3PbI3 filmsWang, Peiqi; Zhao, Jinjin; Wei, Liyu; Zhu, Qingfeng; Xie, Shuhong; Liu, Jinxi; Meng, Xiangjian; Li, JiangyuNanoscale (2017), 9 (11), 3806-3817CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)The photovoltaic conversion efficiency of perovskite solar cells based on org.-inorg. CH3NH3PbI3 has risen spectacularly from 3.8% to over 20% in just seven years, yet quite a few important fundamental issues have not been settled, and the role of spontaneous polarization remains poorly understood. While piezoresponse force microscopy (PFM) has been adopted to probe possible ferroelectricity in CH3NH3PbI3, the reported data are often conflicting and inconclusive, due to the complexity in the apparent piezoresponse and its switching that may arise from ionic motions, electrostatic interactions, and other electromech. mechanisms. Here, using a combination of microscopic and macroscopic measurements, we unambiguously establish the linear piezoelectricity of CH3NH3PbI3 arising from its spontaneous polarization, which can be switched by an elec. field, though other electromech. contributions such as ionic motions are also shown to exist. More importantly, we demonstrate strong interactions between polarization and light in technol. relevant CH3NH3PbI3 films with good conversion efficiencies, observing that the spontaneous polarization can also be switched by light illumination in the absence of an elec. field. The light is shown to reduce the coercive voltage of CH3NH3PbI3 and shifts its nucleation bias, suggesting that the photo-induced switching is caused by ionic motions in combination with a photovoltaic field. This set of studies offer strong evidence on the interactions among photo-induced charges, polarization, and ions in perovskite CH3NH3PbI3, and these fundamental observations lay the ground for answering the technol. important question regarding the effects of ferroelectricity on its photovoltaic conversion.
- 40Rakita, Y.; Bar-Elli, O.; Meirzadeh, E.; Kaslasi, H.; Peleg, Y.; Hodes, G.; Lubomirsky, I.; Oron, D.; Ehre, D.; Cahen, D. Tetragonal CH3NH3PbI3 is ferroelectric Proc. Natl. Acad. Sci. U. S. A. 2017, 114, E5504– E5512 DOI: 10.1073/pnas.170242911440https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXptlSguro%253D&md5=b90071fbf65dbdd83662816c525234fbTetragonal CH3NH3PbI3 is ferroelectricRakita, Yevgeny; Bar-Elli, Omri; Meirzadeh, Elena; Kaslasi, Hadar; Peleg, Yagel; Hodes, Gary; Lubomirsky, Igor; Oron, Dan; Ehre, David; Cahen, DavidProceedings of the National Academy of Sciences of the United States of America (2017), 114 (28), E5504-E5512CODEN: PNASA6; ISSN:0027-8424. (National Academy of Sciences)Halide perovskite (HaP) semiconductors are revolutionizing photovoltaic (PV) solar energy conversion by showing remarkable performance of solar cells made with HaPs, esp. tetragonal methylammonium lead triiodide (MAPbI3). In particular, the low voltage loss of these cells implies a remarkably low recombination rate of photogenerated carriers. It was suggested that low recombination can be due to the spatial sepn. of electrons and holes, a possibility if MAPbI3 is a semiconducting ferroelec., which, however, requires clear exptl. evidence. As a first step, we show that, in operando, MAPbI3 (unlike MAPbBr3) is pyroelec., which implies it can be ferroelec. The next step, proving it is (not) ferroelec., is challenging, because of the material's relatively high elec. conductance (a consequence of an optical band gap suitable for PV conversion) and low stability under high applied bias voltage. This excludes normal measurements of a ferroelec. hysteresis loop, to prove ferroelectricity's hallmark switchable polarization. By adopting an approach suitable for elec. leaky materials as MAPbI3, we show here ferroelec. hysteresis from well-characterized single crystals at low temp. (still within the tetragonal phase, which is stable at room temp.). By chem. etching, we also can image the structural fingerprint for ferroelectricity, polar domains, periodically stacked along the polar axis of the crystal, which, as predicted by theory, scale with the overall crystal size. We also succeeded in detecting clear second harmonic generation, direct evidence for the material's noncentrosymmetry. We note that the material's ferroelec. nature, can, but need not be important in a PV cell at room temp.
- 41Rohm, H.; Leonhard, T.; Hoffmann, M. J.; Colsmann, A. Ferroelectric domains in methylammonium lead iodide perovskite thin-films Energy Environ. Sci. 2017, 10, 950– 955 DOI: 10.1039/C7EE00420FThere is no corresponding record for this reference.
- 42Mosconi, E.; Quarti, C.; Ivanovska, T.; Ruani, G.; De Angelis, F. Structural and electronic properties of organo-halide lead perovskites: a combined IR-spectroscopy and ab initio molecular dynamics investigation Phys. Chem. Chem. Phys. 2014, 16, 16137– 16144 DOI: 10.1039/C4CP00569D42https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2cXhtVGgsbzF&md5=64bb435e1189cfb224043cfbe245f7c4Structural and electronic properties of organo-halide lead perovskites: a combined IR-spectroscopy and ab initio molecular dynamics investigationMosconi, Edoardo; Quarti, Claudio; Ivanovska, Tanja; Ruani, Giampiero; De Angelis, FilippoPhysical Chemistry Chemical Physics (2014), 16 (30), 16137-16144CODEN: PPCPFQ; ISSN:1463-9076. (Royal Society of Chemistry)Organo-halide lead perovskites are revolutionizing the photovoltaic scenario, with efficiencies exceeding 15%. The orientational dynamics disorder of the methylammonium cations (MA) is one of the most peculiar features of these materials. Here, the authors perform ab initio mol. dynamics simulations and IR spectroscopic measurements on lead halide hybrid perovskites to elucidate the rotational motion of the MA cations in these systems and its effects on the structural and electronic properties of hybrid perovskites. In the studied time frame, the MA cations rotate within the inorg. framework on a timescale of a few ps. A variation of ±0.1 to 0.2 eV of the electronic properties with the ion dynamics is found, which increases upon increasing the temp.
- 43Carignano, M. A.; Kachmar, A.; Hutter, J. Thermal effects on CH3NH3PbI3 perovskite from ab initio molecular dynamics simulations J. Phys. Chem. C 2015, 119, 8991– 8997 DOI: 10.1021/jp510568n43https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXjtlChtLY%253D&md5=c17bae31ceef67cc99b7c4c1df6699cdThermal Effects on CH3NH3PbI3 Perovskite from Ab Initio Molecular Dynamics SimulationsCarignano, Marcelo A.; Kachmar, Ali; Hutter, JurgJournal of Physical Chemistry C (2015), 119 (17), 8991-8997CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)We present a mol. dynamics simulation study of CH3NH3PbI3 based on forces calcd. from d. functional theory. The simulations were performed on model systems having 8 and 27 unit cells, and for a total simulation time of 40 ps in each case. Anal. of the finite size effects, in particular the mobility of the org. component, suggests that the smaller system is over-correlated through the long-range electrostatic interaction. In the larger system, this finite size artifact is relaxed, producing a more reliable description of the anisotropic rotational behavior of the methylammonium mols. The thermal effects on the optical properties of the system were also analyzed. The HOMO-LUMO energy gap fluctuates around its central value with a std. deviation of approx. 0.1 eV. The projected d. of states consistently place the Fermi level on the p orbitals of the I atoms and the lowest virtual state on the p orbitals of the Pb atoms throughout the whole simulation trajectory.
- 44Goehry, C.; Nemnes, G. A.; Manolescu, A. Collective behavior of molecular dipoles in CH3NH3PbI3 J. Phys. Chem. C 2015, 119, 19674– 19680 DOI: 10.1021/acs.jpcc.5b0582344https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXht12ks7vE&md5=2137534639fef0fc2643bd2bb1dc7f0eCollective Behavior of Molecular Dipoles in CH3NH3PbI3Goehry, C.; Nemnes, G. A.; Manolescu, A.Journal of Physical Chemistry C (2015), 119 (34), 19674-19680CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)Using ab initio DFT-LDA mol. dynamics simulations the authors studied the thermal motion occurring in perovskite crystals of CH3NH3PbI3. They obtained ests. of the rotational relaxation time of the cation CH3NH3+. We examine the tetragonal and cubic phases, as both may be present under operational conditions. Influenced by each other, and by the tilting of PbI6 octahedra, cations undergo collective motion as their contribution to polarization does not vanish. The modus operandi of formation of microscopic ferroelec. domains is qual. described.
- 45Mattoni, A.; Filippetti, A.; Saba, M. I.; Delugas, P. Methylammonium rotational dynamics in lead halide perovskite by classical molecular dynamics: the role of temperature J. Phys. Chem. C 2015, 119, 17421– 17428 DOI: 10.1021/acs.jpcc.5b0428345https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtVaktb%252FM&md5=a539f35a182f65b105bd37c86e4992ebMethylammonium Rotational Dynamics in Lead Halide Perovskite by Classical Molecular Dynamics: The Role of TemperatureMattoni, A.; Filippetti, A.; Saba, M. I.; Delugas, P.Journal of Physical Chemistry C (2015), 119 (30), 17421-17428CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)An interat. model potential for mol. dynamics is derived from first-principles and used to study the mol. rotations and relaxation times in methylammonium lead halide, here considered the prototypical example of a hybrid crystal with a strong reorientational dynamics. Within the limits of a simple ionic scheme, the potential is able to catch the main qual. features of the material at zero and finite temp. and opens the way to the development of classical potentials for hybrid perovskites. In agreement with expts. and previous theor. findings, the mol. trajectories exhibit a transition from a dynamics dominated by high symmetry directions at low temp. to a fast dynamics at room temp. in which the mol. can reorient quasi-randomly. By computing the angular time correlation function we discuss the reorientational time as a function of temp. in comparison with existing literature, providing a simple model and a clear attribution of the relaxation times in terms of their temp. dependence. This work clarifies the temp. dependence of the relaxation times and the interpretation of the exptl. data in terms of the different mechanisms contributing to the mol. dynamics.
- 46Lahnsteiner, J.; Kresse, G.; Kumar, A.; Sarma, D. D.; Franchini, C.; Bokdam, M. Room-temperature dynamic correlation between methylammonium molecules in lead-iodine based perovskites: An ab initio molecular dynamics perspective Phys. Rev. B: Condens. Matter Mater. Phys. 2016, 94, 214114 DOI: 10.1103/PhysRevB.94.21411446https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXpt1Cru7s%253D&md5=b2cdc4cf471140853e03fbdf7a657607Room-temperature dynamic correlation between methylammonium molecules in lead-iodine based perovskites: an ab initio molecular dynamics perspectiveLahnsteiner, Jonathan; Kresse, Georg; Kumar, Abhinav; Sarma, D. D.; Franchini, Cesare; Bokdam, MennoPhysical Review B (2016), 94 (21), 214114/1-214114/10CODEN: PRBHB7; ISSN:2469-9950. (American Physical Society)The high efficiency of lead organo-metal-halide perovskite solar cells has raised many questions about the role of the methylammonium (MA) mols. in the Pb-I framework. Expts. indicate that the MA mols. are able to "freely" spin around at room temp. even though they carry an intrinsic dipole moment. We have performed large supercell (2592 atoms) finite-temp. ab initio mol. dynamics calcns. to study the correlation between the mols. in the framework. An underlying long-range antiferroelec. ordering of the mol. dipoles is obsd. The dynamical correlation between neighboring mols. shows a max. around room temp. in the mid-temp. phase. In this phase, the rotations are slow enough to (partially) couple to neighbors via the Pb-I cage. This results in a collective motion of neighboring mols. in which the cage acts as the mediator. At lower and higher temps., the motions are less correlated.
- 47Meloni, S.; Moehl, T.; Tress, W.; Franckevičius, M.; Saliba, M.; Lee, Y. H.; Gao, P.; Nazeeruddin, M. K.; Zakeeruddin, S. M.; Rothlisberger, U. Ionic polarization-induced current–voltage hysteresis in CH3NH3PbX3 perovskite solar cells Nat. Commun. 2016, 7, 10334 DOI: 10.1038/ncomms1033447https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XitlChsbc%253D&md5=e09e580b6cf30cd4fa2a52c0732725c3Ionic polarization-induced current-voltage hysteresis in CH3NH3PbX3 perovskite solar cellsMeloni, Simone; Moehl, Thomas; Tress, Wolfgang; Franckevicius, Marius; Saliba, Michael; Lee, Yong Hui; Gao, Peng; Nazeeruddin, Mohammad Khaja; Zakeeruddin, Shaik Mohammed; Rothlisberger, Ursula; Graetzel, MichaelNature Communications (2016), 7 (), 10334CODEN: NCAOBW; ISSN:2041-1723. (Nature Publishing Group)CH3NH3PbX3 (MAPbX3) perovskites have attracted considerable attention as absorber materials for solar light harvesting, reaching solar to power conversion efficiencies above 20%. In spite of the rapid evolution of the efficiencies, the understanding of basic properties of these semiconductors is still ongoing. One phenomenon with so far unclear origin is the so-called hysteresis in the current-voltage characteristics of these solar cells. Here we investigate the origin of this phenomenon with a combined exptl. and computational approach. Exptl. the activation energy for the hysteretic process is detd. and compared with the computational results. First-principles simulations show that the timescale for MA+ rotation excludes a MA-related ferroelec. effect as possible origin for the obsd. hysteresis. On the other hand, the computationally detd. activation energies for halide ion (vacancy) migration are in excellent agreement with the exptl. detd. values, suggesting that the migration of this species causes the obsd. hysteretic behavior of these solar cells.
- 48Kulbak, M.; Gupta, S.; Kedem, N.; Levine, I.; Bendikov, T.; Hodes, G.; Cahen, D. Cesium enhances long-term stability of lead bromide perovskite-based solar cells J. Phys. Chem. Lett. 2016, 7, 167– 172 DOI: 10.1021/acs.jpclett.5b0259748https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXitVygt7rJ&md5=153a43764ddd69522b617fe888a5a387Cesium Enhances Long-Term Stability of Lead Bromide Perovskite-Based Solar CellsKulbak, Michael; Gupta, Satyajit; Kedem, Nir; Levine, Igal; Bendikov, Tatyana; Hodes, Gary; Cahen, DavidJournal of Physical Chemistry Letters (2016), 7 (1), 167-172CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)Direct comparison between perovskite-structured hybrid org.-inorg. methylammonium lead bromide (MAPbBr3) and all-inorg. Cs lead bromide (CsPbBr3), allows identifying possible fundamental differences in their structural, thermal and electronic characteristics. Both materials possess a similar direct optical band gap, but CsPbBr3 demonstrates a higher thermal stability than MAPbBr3. To compare device properties, the authors fabricated solar cells, with similarly synthesized MAPbBr3 or CsPbBr3, over mesoporous TiO2 scaffolds. Both cell types demonstrated comparable photovoltaic performances under AM1.5 illumination, reaching power conversion efficiencies of ∼6% with a poly aryl amine-based deriv. as hole transport material. Further anal. shows that Cs-based devices are as efficient as, and more stable than methylammonium-based ones, after aging (storing the cells for 2 wk in a dry (relative humidity 15-20%) air atm. in the dark) for 2 wk, under const. illumination (at max. power), and under electron beam irradn.
- 49Eperon, G. E.; Paterno, G. M.; Sutton, R. J.; Zampetti, A.; Haghighirad, A. A.; Cacialli, F.; Snaith, H. J. Inorganic caesium lead iodide perovskite solar cells J. Mater. Chem. A 2015, 3, 19688– 19695 DOI: 10.1039/C5TA06398A49https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsVGjtbbJ&md5=f62ebbc17b21bfcff5a5e9c2ae6b80e2Inorganic cesium lead iodide perovskite solar cellsEperon, Giles E.; Paterno, Giuseppe M.; Sutton, Rebecca J.; Zampetti, Andrea; Haghighirad, Amir Abbas; Cacialli, Franco; Snaith, Henry J.Journal of Materials Chemistry A: Materials for Energy and Sustainability (2015), 3 (39), 19688-19695CODEN: JMCAET; ISSN:2050-7496. (Royal Society of Chemistry)The vast majority of perovskite solar cell research has focused on org.-inorg. lead trihalide perovskites. Herein, we present working inorg. CsPbI3 perovskite solar cells for the first time. CsPbI3 normally resides in a yellow non-perovskite phase at room temp., but by careful processing control and development of a low-temp. phase transition route we have stabilized the material in the black perovskite phase at room temp. As such, we have fabricated solar cell devices in a variety of architectures, with current-voltage curve measured efficiency up to 2.9% for a planar heterojunction architecture, and stabilized power conversion efficiency of 1.7%. The well-functioning planar junction devices demonstrate long-range electron and hole transport in this material. Importantly, this work identifies that the org. cation is not essential, but simply a convenience for forming lead triiodide perovskites with good photovoltaic properties. We addnl. observe significant rate-dependent current-voltage hysteresis in CsPbI3 devices, despite the absence of the org. polar mol. previously thought to be a candidate for inducing hysteresis via ferroelec. polarization. Due to its space group, CsPbI3 cannot be a ferroelec. material, and thus we can conclude that ferroelectricity is not required to explain current-voltage hysteresis in perovskite solar cells. Our report of working inorg. perovskite solar cells paves the way for further developments likely to lead to much more thermally stable perovskite solar cells and other optoelectronic devices.
- 50Gesi, K. Effect of hydrostatic pressure on the structural phase transitions in CH3NH3PbX3 (X = Cl, Br, I) Ferroelectrics 1997, 203, 249– 268 DOI: 10.1080/00150199708012851There is no corresponding record for this reference.
- 51Maeda, M.; Hattori, M.; Hotta, A.; Suzuki, I. Dielectric Studies on CH3NH3PbX3 (X = Cl and Br) Single Cystals J. Phys. Soc. Jpn. 1997, 66, 1508– 1511 DOI: 10.1143/JPSJ.66.150851https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2sXjs1Cnurg%253D&md5=5c1c573b0511308d91e9960e70ffa948Dielectric studies on CH3NH3PbX3 (X = Cl and Br) single crystalsMaeda, Masaki; Hattori, Maki; Hotta, Akifumi; Suzuki, IkuoJournal of the Physical Society of Japan (1997), 66 (5), 1508-1511CODEN: JUPSAU; ISSN:0031-9015. (Physical Society of Japan)Dielec. dispersion measurements have been performed on CH3NH3PbX3 (MAPbX3, X = Cl and Br) single crystals at frequencies between 50 Hz and 1 MHz. Significant dielec. dispersion was obsd. in the cubic and tetragonal II phases for MAPbCl3 and in the cubic, tetragonal I and tetragonal II phases for MAPbBr3. The apparent dielec. dispersion is attributed to the ionic cond. in the crystals. The static bulk cond. is expressed by the Arrhenius-type formula σ = (A/T)exp(-ΔE/kT). The activation energies for ionic conduction along [100] axis for each phase are estd. to be 0.13 eV (cubic phase) for MAPbCl3 and 0.132 eV (cubic phase) and 1.60 eV (tetragonal I phase) for MAPbBr3.
- 52Chen, Y.-F.; Tsai, Y.-T.; Bassani, D. M.; Hirsch, L. Experimental evidence of the anti-parallel arrangement of methylammonium ions in perovskites Appl. Phys. Lett. 2016, 109, 213504 DOI: 10.1063/1.496857952https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhvFGru7jJ&md5=5c2ff81a66f64f07da4bf1c24d435b19Experimental evidence of the anti-parallel arrangement of methylammonium ions in perovskitesChen, Yan-Fang; Tsai, Yu-Tang; Bassani, Dario M.; Hirsch, LionelApplied Physics Letters (2016), 109 (21), 213504/1-213504/4CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)Orientation arrangement of methylammonium ions in hybrid org.-inorg. perovskite is still under debate because their tendency for alignment is expected to give rise to either ferroelec. or anti-ferroelec. behavior, which may influence the perovskite device performance. To resolve the debate surrounding the alignment of the org. cations in perovskite materials, we studied the dipole orientation by analyzing the dielec. properties of the material. The dielec. permittivity has been investigated as a function of temp. with the data analyzed using the Kirkwood-Frohlich-Onsager theory. From these results, we provide exptl. evidence of the anti-parallel arrangement of methylammonium ions in hybrid org.-inorg. perovskite. (c) 2016 American Institute of Physics.
- 53Ang, C.; Yu, Z.; Youn, H. J.; Randall, C. A.; Bhalla, A. S.; Cross, L. E.; Nino, J.; Lanagan, M. Low-temperature dielectric relaxation in the pyrochlore (Bi3/4Zn1/4)2(Zn1/4Ta3/4)2O7 compound Appl. Phys. Lett. 2002, 80, 4807– 4809 DOI: 10.1063/1.148604553https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD38Xkslelu7c%253D&md5=6fa5d8bb0eb4787c0687ab296721e24aLow-temperature dielectric relaxation in the pyrochlore (Bi3/4Zn1/4)2(Zn1/4Ta3/4)2O7 compoundAng, Chen; Yu, Zhi; Youn, H. J.; Randall, C. A.; Bhalla, A. S.; Cross, L. E.; Nino, J.; Lanagan, M.Applied Physics Letters (2002), 80 (25), 4807-4809CODEN: APPLAB; ISSN:0003-6951. (American Institute of Physics)The dielec. behavior of the pyrochlore (Bi3/4Zn1/4)2(Zn1/4Ta3/4)2O7 compd. has been studied. A low-temp. dielec. relaxation was obsd. in a low-permittivity matrix with ε = ∼60. The dielec. relaxation process follows a modified Debye model in the vicinity of the relaxation peak, and the relaxation rate follows the Arrhenius law in the wide frequency range 102 to ∼1010 Hz. The temp. intensity of dielec. peaks are independent of d.c. bias (≤60 kV/cm). The dielec. relaxation is tentatively attributed to the hopping of Zn/Bi ions at A sites with more than one equiv. potential min., and the reorientation of the dipoles probably formed through interactions with the "seventh oxygen" and the Bi/Zn A-site ions in the pyrochlore (Bi3/4Zn1/4)2(Zn1/4Ta3/4)2O7 compd.
- 54Noh, J. H.; Im, S. H.; Heo, J. H.; Mandal, T. N.; Seok, S. I. Chemical management for colorful, efficient, and stable inorganic–organic hybrid nanostructured solar cells Nano Lett. 2013, 13, 1764– 1769 DOI: 10.1021/nl400349b54https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXksVyit7w%253D&md5=6279f57e41e3bc9eb469af9b0baa3149Chemical Management for Colorful, Efficient, and Stable Inorganic-Organic Hybrid Nanostructured Solar CellsNoh, Jun Hong; Im, Sang Hyuk; Heo, Jin Hyuck; Mandal, Tarak N.; Seok, Sang IlNano Letters (2013), 13 (4), 1764-1769CODEN: NALEFD; ISSN:1530-6984. (American Chemical Society)Chem. tuned inorg.-org. hybrid materials, based on MeNH3(=MA)Pb(I1-xBrx)3 perovskites, have been studied using UV-visible absorption and x-ray diffraction patterns and applied to nanostructured solar cells. The band gap engineering brought about by the chem. management of MAPb(I1-xBrx)3 perovskites can be controllably tuned to cover almost the entire visible spectrum, enabling the realization of colorful solar cells. The authors demonstrate highly efficient solar cells exhibiting 12.3% in a power conversion efficiency of under std. AM 1.5, for the most efficient device, as a result of tunable compn. for the light harvester in conjunction with a mesoporous TiO2 film and a hole conducting polymer. Probably the works highlighted in this paper represent one step toward the realization of low-cost, high-efficiency, and long-term stability with colorful solar cells.
- 55Stoumpos, C. C.; Malliakas, C. D.; Peters, J. A.; Liu, Z.; Sebastian, M.; Im, J.; Chasapis, T. C.; Wibowo, A. C.; Chung, D. Y.; Freeman, A. J. Crystal growth of the perovskite semiconductor CsPbBr3: a new material for high-energy radiation detection Cryst. Growth Des. 2013, 13, 2722– 2727 DOI: 10.1021/cg400645t55https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXosFyitLc%253D&md5=615d4e50e40aa9c8cb77e787ec333bb9Crystal Growth of the Perovskite Semiconductor CsPbBr3: A New Material for High-Energy Radiation DetectionStoumpos, Constantinos C.; Malliakas, Christos D.; Peters, John A.; Liu, Zhifu; Sebastian, Maria; Im, Jino; Chasapis, Thomas C.; Wibowo, Arief C.; Chung, Duck Young; Freeman, Arthur J.; Wessels, Bruce W.; Kanatzidis, Mercouri G.Crystal Growth & Design (2013), 13 (7), 2722-2727CODEN: CGDEFU; ISSN:1528-7483. (American Chemical Society)The synthesis, crystal growth, and structural and optoelectronic characterization was carried out for the perovskite compd. CsPbBr3. This compd. is a direct band gap semiconductor which meets most of the requirements for successful detection of X- and γ-ray radiation, such as high attenuation, high resistivity, and significant photocond. response, with detector resoln. comparable to that of com., state-of-the-art materials. A structural phase transition which occurs during crystal growth at higher temp. does not seem to affect its crystal quality. Its μτ product for both hole and electron carriers is approx. equal. The μτ product for electrons is comparable to Cd Zn telluride (CZT) and that for holes is 10 times higher than CZT.
- 56Saidaminov, M. I.; Abdelhady, A. L.; Murali, B.; Alarousu, E.; Burlakov, V. M.; Peng, W.; Dursun, I.; Wang, L.; He, Y.; Maculan, G. High-quality bulk hybrid perovskite single crystals within minutes by inverse temperature crystallization Nat. Commun. 2015, 6, 7586 DOI: 10.1038/ncomms858656https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC28%252FgvFWltg%253D%253D&md5=8b92f9296104d2abbfc6075816e68ee6High-quality bulk hybrid perovskite single crystals within minutes by inverse temperature crystallizationSaidaminov Makhsud I; Abdelhady Ahmed L; Murali Banavoth; Alarousu Erkki; Peng Wei; Dursun Ibrahim; Maculan Giacomo; Mohammed Omar F; Bakr Osman M; Abdelhady Ahmed L; Burlakov Victor M; Goriely Alain; Wang Lingfei; Wu Tom; He YaoNature communications (2015), 6 (), 7586 ISSN:.Single crystals of methylammonium lead trihalide perovskites (MAPbX3; MA = CH3NH3(+), X = Br(-) or I(-)) have shown remarkably low trap density and charge transport properties; however, growth of such high-quality semiconductors is a time-consuming process. Here we present a rapid crystal growth process to obtain MAPbX3 single crystals, an order of magnitude faster than previous reports. The process is based on our observation of the substantial decrease of MAPbX3 solubility, in certain solvents, at elevated temperatures. The crystals can be both size- and shape-controlled by manipulating the different crystallization parameters. Despite the rapidity of the method, the grown crystals exhibit transport properties and trap densities comparable to the highest quality MAPbX3 reported to date. The phenomenon of inverse or retrograde solubility and its correlated inverse temperature crystallization strategy present a major step forward for advancing the field on perovskite crystallization.
- 57Im, J. H.; Lee, C. R.; Lee, J. W.; Park, S. W.; Park, N. G. 6.5% Efficient perovskite quantum-dot-sensitized solar cell Nanoscale 2011, 3, 4088– 4093 DOI: 10.1039/c1nr10867k57https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXhtlWitr%252FI&md5=21c01ce5d671970b109bd1a98fd6734f6.5% efficient perovskite quantum-dot-sensitized solar cellIm, Jeong-Hyeok; Lee, Chang-Ryul; Lee, Jin-Wook; Park, Sang-Won; Park, Nam-GyuNanoscale (2011), 3 (10), 4088-4093CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)Highly efficient quantum-dot-sensitized solar cell is fabricated using ca. 2-3 nm sized perovskite (CH3NH3)PbI3 nanocrystal. Spin-coating of the equimolar mixt. of CH3NH3I and PbI2 in γ-butyrolactone soln. (perovskite precursor soln.) leads to (CH3NH3)PbI3 quantum dots (QDs) on nanocryst. TiO2 surface. By electrochem. junction with iodide/iodine based redox electrolyte, perovskite QD-sensitized 3.6 μm-thick TiO2 film shows max. external quantum efficiency (EQE) of 78.6% at 530 nm and solar-to-elec. conversion efficiency of 6.54% at AM 1.5G 1 sun intensity (100 mW cm-2), which is by far the highest efficiency among the reported inorg. quantum dot sensitizers.
- 58Kulbak, M.; Cahen, D.; Hodes, G. How important is the organic part of lead halide perovskite photovoltaic cells? Efficient CsPbBr3 cells J. Phys. Chem. Lett. 2015, 6, 2452– 2456 DOI: 10.1021/acs.jpclett.5b0096858https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhtVaksb3I&md5=2c21efab962ecdbecd4dfe43526d22cfHow Important Is the Organic Part of Lead Halide Perovskite Photovoltaic Cells? Efficient CsPbBr3 CellsKulbak, Michael; Cahen, David; Hodes, GaryJournal of Physical Chemistry Letters (2015), 6 (13), 2452-2456CODEN: JPCLCD; ISSN:1948-7185. (American Chemical Society)Hybrid org.-inorg. lead halide perovskite photovoltaic cells have already surpassed 20% conversion efficiency in the few years that they have been seriously studied. However, many fundamental questions still remain unanswered as to why they are so good. One of these is "Is the org. cation really necessary to obtain high quality cells" In this study, we show that an all-inorg. version of the lead bromide perovskite material works equally well as the org. one, in particular generating the high open circuit voltages that are an important feature of these cells.
- 59Blöchl, P. E. Projector augmented-wave method Phys. Rev. B: Condens. Matter Mater. Phys. 1994, 50, 17953– 17979 DOI: 10.1103/PhysRevB.50.1795359https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2sfjslSntA%253D%253D&md5=1853d67af808af2edab58beaab5d3051Projector augmented-wave methodBlochlPhysical review. B, Condensed matter (1994), 50 (24), 17953-17979 ISSN:0163-1829.There is no expanded citation for this reference.
- 60Kresse, G.; Hafner, J. Ab initio molecular dynamics for liquid metals Phys. Rev. B: Condens. Matter Mater. Phys. 1993, 47, 558– 561 DOI: 10.1103/PhysRevB.47.55860https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK3sXlt1Gnsr0%253D&md5=c9074f6e1afc534b260d29dd1846e350Ab initio molecular dynamics of liquid metalsKresse, G.; Hafner, J.Physical Review B: Condensed Matter and Materials Physics (1993), 47 (1), 558-61CODEN: PRBMDO; ISSN:0163-1829.The authors present ab initio quantum-mech. mol.-dynamics calcns. based on the calcn. of the electronic ground state and of the Hellmann-Feynman forces in the local-d. approxn. at each mol.-dynamics step. This is possible using conjugate-gradient techniques for energy minimization, and predicting the wave functions for new ionic positions using sub-space alignment. This approach avoids the instabilities inherent in quantum-mech. mol.-dynamics calcns. for metals based on the use of a factitious Newtonian dynamics for the electronic degrees of freedom. This method gives perfect control of the adiabaticity and allows one to perform simulations over several picoseconds.
- 61Kresse, G.; Furthmüller, J. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set Phys. Rev. B: Condens. Matter Mater. Phys. 1996, 54, 11169– 11186 DOI: 10.1103/PhysRevB.54.1116961https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28Xms1Whu7Y%253D&md5=9c8f6f298fe5ffe37c2589d3f970a697Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis setKresse, G.; Furthmueller, J.Physical Review B: Condensed Matter (1996), 54 (16), 11169-11186CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)The authors present an efficient scheme for calcg. the Kohn-Sham ground state of metallic systems using pseudopotentials and a plane-wave basis set. In the first part the application of Pulay's DIIS method (direct inversion in the iterative subspace) to the iterative diagonalization of large matrixes will be discussed. This approach is stable, reliable, and minimizes the no. of order Natoms3 operations. In the second part, we will discuss an efficient mixing scheme also based on Pulay's scheme. A special "metric" and a special "preconditioning" optimized for a plane-wave basis set will be introduced. Scaling of the method will be discussed in detail for non-self-consistent and self-consistent calcns. It will be shown that the no. of iterations required to obtain a specific precision is almost independent of the system size. Altogether an order Natoms2 scaling is found for systems contg. up to 1000 electrons. If we take into account that the no. of k points can be decreased linearly with the system size, the overall scaling can approach Natoms. They have implemented these algorithms within a powerful package called VASP (Vienna ab initio simulation package). The program and the techniques have been used successfully for a large no. of different systems (liq. and amorphous semiconductors, liq. simple and transition metals, metallic and semiconducting surfaces, phonons in simple metals, transition metals, and semiconductors) and turned out to be very reliable.
- 62Kresse, G.; Joubert, D. From ultrasoft pseudopotentials to the projector augmented-wave method Phys. Rev. B: Condens. Matter Mater. Phys. 1999, 59, 1758– 1775 DOI: 10.1103/PhysRevB.59.175862https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK1MXkt12nug%253D%253D&md5=78a73e92a93f995982fc481715729b14From ultrasoft pseudopotentials to the projector augmented-wave methodKresse, G.; Joubert, D.Physical Review B: Condensed Matter and Materials Physics (1999), 59 (3), 1758-1775CODEN: PRBMDO; ISSN:0163-1829. (American Physical Society)The formal relationship between ultrasoft (US) Vanderbilt-type pseudopotentials and Blochl's projector augmented wave (PAW) method is derived. The total energy functional for US pseudopotentials can be obtained by linearization of two terms in a slightly modified PAW total energy functional. The Hamilton operator, the forces, and the stress tensor are derived for this modified PAW functional. A simple way to implement the PAW method in existing plane-wave codes supporting US pseudopotentials is pointed out. In addn., crit. tests are presented to compare the accuracy and efficiency of the PAW and the US pseudopotential method with relaxed-core all-electron methods. These tests include small mols. (H2, H2O, Li2, N2, F2, BF3, SiF4) and several bulk systems (diamond, Si, V, Li, Ca, CaF2, Fe, Co, Ni). Particular attention is paid to the bulk properties and magnetic energies of Fe, Co, and Ni.
- 63Perdew, J. P.; Ruzsinszky, A.; Csonka, G. I.; Vydrov, O. A.; Scuseria, G. E.; Constantin, L. A.; Zhou, X.; Burke, K. Restoring the density-gradient expansion for exchange in solids and surfaces Phys. Rev. Lett. 2008, 100, 136406 DOI: 10.1103/PhysRevLett.100.13640663https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXktlygt7c%253D&md5=bb5e35a295ab7af85d65ac410d6f898cRestoring the Density-Gradient Expansion for Exchange in Solids and SurfacesPerdew, John P.; Ruzsinszky, Adrienn; Csonka, Gabor I.; Vydrov, Oleg A.; Scuseria, Gustavo E.; Constantin, Lucian A.; Zhou, Xiaolan; Burke, KieronPhysical Review Letters (2008), 100 (13), 136406/1-136406/4CODEN: PRLTAO; ISSN:0031-9007. (American Physical Society)Popular modern generalized gradient approxns. are biased toward the description of free-atom energies. Restoration of the first-principles gradient expansion for exchange over a wide range of d. gradients eliminates this bias. We introduce a revised Perdew-Burke-Ernzerhof generalized gradient approxn. that improves equil. properties of densely packed solids and their surfaces.
- 64Allen, M. P.; Tildesley, D. J. Computer Simulation of Liquids; Oxford University Press, 1991.There is no corresponding record for this reference.
Supporting Information
Supporting Information
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.jpclett.7b01740.
Powder XRD patterns, dielectric data up to higher temperature, polynomial fits to SHG spectra, and residuals of polynomial fits (PDF)
Terms & Conditions
Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system: http://pubs.acs.org/page/copyright/permissions.html.