Vibronic Coupling Effect on the Vibrationally Resolved Electronic Spectra and Intersystem Crossing Rates of a TADF Emitter: 7-PhQAD

2022 ◽  
Author(s):  
Sirong Lin ◽  
Zheng Pei ◽  
Bin Zhang ◽  
Huili Ma ◽  
WanZhen Liang
Keyword(s):  
Electronic Spectra ◽  
Coupling Effect ◽  
Vibronic Coupling ◽  
Intersystem Crossing

scholarly journals Herzberg-Teller Vibronic Coupling Effect on the Vibrationally-Resolved Electronic Spectra and Intersystem Crossing Rates of a TADF Emitter: 7-PhQAD

2021 ◽  
Author(s):  
Sirong Lin ◽  
Zheng Pei ◽  
Bin Zhang ◽  
Huili Ma ◽  
Wanzhen Liang
Keyword(s):  
Density Functional ◽  
Energy Gap ◽  
Coupling Effect ◽  
Delayed Fluorescence ◽  
Vibronic Coupling ◽  
Time Dependent ◽  
Rate Coefficients ◽  
Quantitative Prediction ◽  
Intersystem Crossing ◽  
Triplet Energy

Assessing and improving the performance of organic light-emitting diode (OLED) materials require quantitative prediction of rate coefficients for the intersystem crossing (ISC) and reverse ISC (RISC) processes, which are determined not only by the singlet-triplet energy gap and the direct spin-orbit coupling (SOC) at a thermal equilibrium position of the initial electronic state but also by the non-Condon effects such as the Herzberg-Teller vibronic coupling (HTVC) and the spin-vibronic coupling (SVC). Here we applied the time-dependent correlation function approaches to calculate the vibronic absorption and fluorescence spectra and ISC and RISC rates of a newly synthesized multiple-resonance-type (MR-type) thermally activated delayed fluorescence (TADF) emitter, 7-phenylquinolino[3,2,1-de]acridine-5,9-dione (7-PhQAD), with inclusion of the Franck-Condon (FC), HTVC, and Duschinsky rotation effects. It is found that the experimentally-measured ISC rate of 7-PhQAD originates predominantly from the HTVC which increases the ISC rate by more than one order of magnitude while the HTVC effect on the vibronic spectra is negligible. The small discrepancy between the theoretical and experimental rates originates from the neglect of the second-order SVC and the inaccurate excited states calculated by the single-reference time-dependent density functional theory. This work provides a demonstration of what proportion of ISC and RISC rate coefficients of a MR-type TADF emitter can be covered by the contribution of HTVC, and opens design routes that go beyond the FC approximation for the future development of high-performance systems.

Theoretical and Experimental Investigations on the Aggregation‐Enhanced Emission from Dark State: Vibronic Coupling Effect

2020 ◽  
Vol 6 (7) ◽  
pp. 2000255
Author(s):  
Ping‐An Yin ◽  
Qing Wan ◽  
Yingli Niu ◽  
Qian Peng ◽  
Zhiming Wang ◽  
...  
Keyword(s):  
Coupling Effect ◽  
Vibronic Coupling ◽  
Experimental Investigations ◽  
Dark State

ChemInform Abstract: ELECTRONIC SPECTRA AND VIBRONIC COUPLING OF PYRAZINE

1974 ◽  
Vol 5 (41) ◽  
Author(s):  
ISAMU SUZUKA ◽  
NAOHIKO MIKAMI ◽  
MITSUO ITO
Keyword(s):  
Electronic Spectra ◽  
Vibronic Coupling
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