Zhang Maomao, Lu Qiuxia, Liu Xiaojing, An Zhong
College of Physics and Hebei Advanced Thin Film Laboratory, Hebei Normal University, Shijiazhuang 050024, Hebei, P. R. China.
Phys Chem Chem Phys. 2023 Jul 26;25(29):19620-19625. doi: 10.1039/d3cp00959a.
In polymer solar cells (PSCs), the contribution of hot excitons to charge generation is strongly limited by their relatively low yield and ultrafast internal conversion (IC) process. In recent years, different strategies have been proposed to modulate the hot exciton dynamics, but a direct correlation between the microscopic properties of the polymer and hot exciton dynamics is still not completely clear. Here, we theoretically investigate the effect of intramolecular disorder, including the diagonal disorder (DD) and off-diagonal disorder (ODD), on the hot exciton dynamics based on the tight-binding model calculations. We find that the effect of ODD on the hot exciton yield is more significant than that of DD. In addition, we find that the IC relaxation time of hot excitons depends nonmonotonically on the intensity of DD and ODD, indicating that the intramolecular disorder can modulate the competitive relationship between the spontaneous dissociation of hot excitons and the IC process. This work provides a guide for promoting charge generation in PSCs dominated by hot exciton dissociation.
