Singlet fission, which generates two electrons from a single photon, may be used to increase the theoretical efficiency of a photovoltaic cell beyond the Shockley-Queisser limit. Despite of intense research over decades, the underlying molecular mechanism is still obscured and little is known about how to make the singlet fission most efficient. More theoretical work is called to provide a full microscopic picture of singlet fission. In this work, the recently developed symmetrical quasi-classical method has been applied to a model system for molecular dimers of polyacenes, a family of organic materials for highly efficient solar energy conversion by using singlet fission. Our results describe the coherent dynamics of singlet fission very well for the model system, in good agreement with those recently obtained by using Redfield theory. In contrast, this new method can provide accurate microscopic details about non-adiabatic molecular dynamics unlike many other methods based on perturbation theory, such as Redfield theory, Forster theory or non-interacting blip approximation. Furthermore it is almost as efficient as the classical molecular dynamics simulation therefore has a potential to be implemented to real complex molecular systems, such as singlet fission materials.

Electronically non-adiabatic dynamics in singlet fission: A quasi-classical trajectory simulation

248th National Meeting (2014)

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