(Invited) Influence of Vibronic Interaction of Charge Transfer Excitons in PTB7/BTA-Based Nonfullerene Organic Solar Cells

For the design of rational D/A interfaces, it is important to elucidate the dynamic processes of excitons generated at the D/A stacking structure interface and the photoelectric conversion mechanism. We predict that the charge-transfer excitons initially formed are weakly bound electron-hole polaron pairs, which dissociate without relaxing to the charge-transfer state and diffuse as free electron polarons and hole polarons. We consider this to be a nonadiabatic process due to oscillatory interactions in the initial charge-transfer excitonic state. In this study, we use time-dependent DFT to investigate the electronic structure, electron-hole distance, electron coupling in charge transfer state generated by photoexcitaion and the Huang- Rhys factors of the D/A complex BTA x , PCTBT/BTA x and PDCBT/BTA x ( x = 1, 3 )) in the excited state and the exciton-phonon coupling and nonadiabatic process. Based on the above, we aim to elucidate the role of vibronic interactions in CT excitonic states and the control of J SC and electron-hole recombination.