Reducing non-radiative charge recombination is of critical importance to achieving high-performance organic photovoltaic (OPV) cells. The correlation between the exciton behaviors and non-radiative charge recombination is rarely studied. In this work, we achieved an increase in the exciton diffusion length (L_D) in the acceptor phase via introducing HDO-4Cl to the PBDB-TF:eC9-based system. Compared with the eC9-based film, the exciton L_D in the HDO-4Cl:eC9-based film is increased from 12.2 to 16.3 nm. The enlarged exciton L_D can obviously decrease the non-radiative charge recombination and increase the efficiency of photon utilization in the PBDB-TF:eC9-based OPV cell. Finally, we not only obtained an outstanding power conversion efficiency (PCE) of 18.86% but also demonstrated the correlations between the non-radiative energy loss and exciton behaviors. The results show that regulating the exciton behaviors is an effective way to reduce the non-radiative energy loss and realize high-efficiency OPV cells.

减少非辐射电荷复合对于实现高性能有机光伏 (OPV) 电池至关重要。激子行为与非辐射电荷复合之间的相关性很少被研究。在这项工作中，我们通过将 HDO-4Cl 引入基于 PBDB-TF:eC9 的系统，实现了受体相中激子扩散长度 ( L _D )的增加。与基于 eC9 的薄膜相比，基于HDO-4Cl:eC9 的薄膜中的激子L _D从 12.2 nm 增加到 16.3 nm。放大激子L _D可以明显减少非辐射电荷复合并提高基于 PBDB-TF:eC9 的 OPV 电池中的光子利用效率。最后，我们不仅获得了 18.86% 的出色功率转换效率 (PCE)，而且还证明了非辐射能量损失与激子行为之间的相关性。结果表明，调节激子行为是减少非辐射能量损失和实现高效OPV电池的有效途径。