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Energy Transfer Dynamics in Triplet–Triplet Annihilation Upconversion Using a Bichromophoric Heavy-Atom-Free Sensitizer

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    Energy Transfer Dynamics in Triplet–Triplet Annihilation Upconversion Using a Bichromophoric Heavy-Atom-Free Sensitizer
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    • Qi Chen
      Qi Chen
      Beijing National Laboratory for Molecular Sciences (BNLMS), Center for Soft Matter Science and Engineering, Key Lab of Polymer Chemistry & Physics of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
      More by Qi Chen
    • Yiming Liu
      Yiming Liu
      Beijing National Laboratory for Molecular Sciences (BNLMS), Center for Soft Matter Science and Engineering, Key Lab of Polymer Chemistry & Physics of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
      More by Yiming Liu
    • Xinyan Guo
      Xinyan Guo
      Beijing National Laboratory for Molecular Sciences (BNLMS), Center for Soft Matter Science and Engineering, Key Lab of Polymer Chemistry & Physics of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
      More by Xinyan Guo
    • Jiang Peng
      Jiang Peng
      Beijing National Laboratory for Molecular Sciences (BNLMS), Center for Soft Matter Science and Engineering, Key Lab of Polymer Chemistry & Physics of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
      More by Jiang Peng
    • Sofia Garakyaraghi
      Sofia Garakyaraghi
      Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
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      Orcidhttp://orcid.org/0000-0001-7835-1888
    • Christopher M. Papa
      Christopher M. Papa
      Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
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    • Felix N. Castellano*
      Felix N. Castellano
      Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
      *F. N. Castellano. E-mail: [email protected]
      More by Felix N. Castellano
      Orcidhttp://orcid.org/0000-0001-7546-8618
    • Dahui Zhao*
      Dahui Zhao
      Beijing National Laboratory for Molecular Sciences (BNLMS), Center for Soft Matter Science and Engineering, Key Lab of Polymer Chemistry & Physics of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
      *D. Zhao. E-mail: [email protected]
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      Orcidhttp://orcid.org/0000-0002-4983-4060
    • Yuguo Ma*
      Yuguo Ma
      Beijing National Laboratory for Molecular Sciences (BNLMS), Center for Soft Matter Science and Engineering, Key Lab of Polymer Chemistry & Physics of Ministry of Education, College of Chemistry, Peking University, Beijing 100871, China
      *Y. Ma. E-mail: [email protected]
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      Orcidhttp://orcid.org/0000-0002-6174-8720
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    The Journal of Physical Chemistry A

    Cite this: J. Phys. Chem. A 2018, 122, 33, 6673–6682
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    https://doi.org/10.1021/acs.jpca.8b05901
    Published July 27, 2018
    Copyright © 2018 American Chemical Society
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    Abstract

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    A heavy-atom-free triplet sensitizer suitable for triplet–triplet annihilation-based photon upconversion was developed from the thermally activated delayed fluorescence (TADF) molecule 4CzPN by covalently tethering a pyrene derivative (DBP) as a triplet acceptor. The triplet exciton produced by 4CzPN is captured by the intramolecular pyrenyl acceptor and subsequently transferred via intermolecular triplet–triplet energy transfer (TTET) to freely diffusing pyrenyl acceptors in toluene. Transient absorption and time-resolved photoluminescence spectroscopy were employed to examine the dynamics of both the intra- and intermolecular TTET processes, and the results indicate that the intramolecular energy transfer from 4CzPN to DBP is swift, quantitative, and nearly irreversible. The reverse intersystem crossing is suppressed while intersystem crossing remains efficient, achieving high triplet yield and long triplet lifetime simultaneously. The ultralong excited state lifetime characteristic of the DBP triplet was shown to be crucial for enhancing the intermolecular TTET efficiency and the subsequent triplet–triplet annihilation photochemistry. It was also demonstrated that with the long triplet lifetime of the tethered DBP, TTET was enabled under low free acceptor concentrations and/or with sluggish molecular diffusion in polymer matrixes.

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    The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.jpca.8b05901.

    • Additional transient absorption spectra and kinetics, time-resolved fluorescence data, Stern–Volmer analysis in toluene and PU films, and kinetic analysis of intra- and intermolecular energy transfer processes (PDF)

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    The Journal of Physical Chemistry A

    Cite this: J. Phys. Chem. A 2018, 122, 33, 6673–6682
    Click to copy citationCitation copied!
    https://doi.org/10.1021/acs.jpca.8b05901
    Published July 27, 2018
    Copyright © 2018 American Chemical Society
    Request reuse permissions

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