Modulating charge transfer rate and efficiency through temperature in organic donor/acceptor systems

Temperature plays a pivotal role in organic photovoltaic processes, yet its influence on interfacial charge transfer dynamics remains controversial. In this work, we develop an organic donor/acceptor model that explicitly incorporates finite-temperature effects and femtosecond electric pump pulses in the dynamical simulations. By using nonadiabatic molecular dynamics, our results demonstrate that electron–phonon coupling is an important condition for interfacial charge transfer to occur. Moreover, temperature exerts a dual regulatory effect. On one hand, thermal activation enhances molecular vibrations, significantly accelerating charge transfer. On the other hand, higher temperatures cause the electronic states to become more symmetrically distributed between the donor and the acceptor, thereby slightly suppressing the net transferred charge. Finally, the robustness and generality of these findings are confirmed through systematic variations in photoexcitation intensity and system size.