Understanding Correlation Among Electron-Phonon-Spin Degree of Freedom in Advanced Molecular Optoelectronics

  • IMS-FHI Joint Online Seminar
  • Date: Jul 4, 2022
  • Time: 10:00 AM (Local Time Germany)
  • Speaker: Kiyoshi Miyata
  • Department of Chemistry, Kyushu University
  • Host: Takashi Kumagai
Understanding Correlation Among Electron-Phonon-Spin Degree of Freedom in Advanced Molecular Optoelectronics
Microscopic understanding of exciton and carrier physics in molecular materials for optoelectronics is a great challenge because of their complexity resulting from strong electron-phonon coupling and perhaps interaction to spin degree of freedom;

e.g. superior optoelectronic properties of lead-halide perovskites materials likely originate from its unique electron-phonon coupled dielectric screening of carriers [1,2], electron spin-flip of intersystem crossing in molecular optoelectronic materials are strongly connected to molecular geometries in the excited states and vibronic coupling [3,4], and singlet fission, ultrafast generation of a correlated triplet pair state from a singlet excited state, is viewed as an extreme example of a concerted process of electron-phonon-spin degrees of freedom [5,6]. Here, I would like to discuss a few topics mainly focusing on thermally activated delayed fluorescence and singlet fission materials regarding the quest to understand the functions using various time-resolved spectroscopy.
[1] H. Zhu , K. Miyata , Y. Fu, J. Wang, P. P. Joshi, D. Niesner, K. W. Williams, S. Jin, X.-Y. Zhu, “Screening in crystalline liquids protects energetic carriers in hybrid perovskites”, Science 353, 1409-1413 (2016).
[2] K. Miyata, D. Meggiolaro, M. T. Trinh, P. P. Joshi, E. Mosconi, S. C. Jones, F. D. Angelis, X.- Y. Zhu, “Large polarons in lead halide perovskites”, Science Advances 3, e1701217 (2017).
[3] K. Miyata, Y. Kurashige, K. Watanabe, T. Sugimoto, S. Takahashi, S. Tanaka, J. Takeya, T. Yanai, Y. Matsumoto, “Coherent singlet fission activated by symmetry breaking”, Nature Chem. 9, 983-989 (2017).
[4] K. Miyata, F. S. Conrad-Burton, F. L. Geyer, X.-Y. Zhu, “Triplet pair states in singlet fission”, Chem. Rev. 119, 4261-4292 (2019).
[5] M. Saigo, K. Miyata, S. Tanaka, H. Nakanotani, C. Adachi, K. Onda, “Suppression of Structural Change upon S –T Conversion Assists the Thermally Activated Delayed Fluorescence Process in Carbazole-Benzonitrile Derivatives”,
J. Phys. Chem. Lett. 10, 2475-2480 (2019).
[6] Y. Shimoda, K. Miyata*, M. Saigo, Y. Tsuchiya, C. Adachi, K. Onda, “Intramolecular-rotation driven triplet-to-singlet upconversion and fluctuation induced fluorescence activation in linearly connected donor–acceptor molecules”,
J. Chem. Phys. 153, 204702 (2020).

Meeting ID: 831 6475 6176
Passcode: E+!3!U3Uia

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