Dresden 2026 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 53: Hybrid, Organic and Perovskite Optoelectronics and Photovoltaics VII
CPP 53.5: Talk
Friday, March 13, 2026, 10:45–11:00, ZEU/LICH
The influence of vibrations on charge and energy transfer dynamics in a singlet fission donor-acceptor complex — •Karin S. Thalmann1, Johan E. Runeson1, Pedro B. Coto2, and Michael Thoss1 — 1Institute of Physics, University of Freiburg, Germany — 2Spanish National Research Council (CSIC), Madrid, Spain
Singlet fission is a photophysical process in molecular materials transforming a singlet excited electronic state to two triplet states [1], effectively doubling the number of charge carriers. This makes molecules exhibiting singlet fission possible candidates to increase the efficiency of solar cells beyond the Shockley-Queisser limit. To investigate this possibility, we analyse the charge and energy transfer dynamics in a donor-acceptor complex consisting of a bis(diazadiborine)-based chromophore [2] and tetracyanoquinodimethane. Using a combined approach of ab initio multireference perturbation theory calculations and quantum dynamical simulations based on a harmonic vibronic coupling Hamiltonian [3], we reveal competing charge and energy transfer mechanisms, such as singlet fission-based transfer and energy decay channels. Further, we expand our model Hamiltonian to include all vibrational degrees of freedom and the anharmonicity in the vibrational modes of the chromophore. The use of mixed quantum-classical approaches allows us to analyse the influence of these vibrational modes on the dynamics as well as the charge and energy transfer mechanisms.
[1] M. B. Smith et al., Chem. Rev. 110, 6891-6936 (2010).
[2] T. Zeng, J. Phys. Chem. Lett. 7, 4405-4412 (2016).
[3] S. R. Reddy et al., J. Chem. Phys. 151, 044307 (2019).
Keywords: Singlet fission; Donor-acceptor complex; Dynamical simulations; Anharmonicity; Transfer mechanisms