Side chain engineering plays a substantial role for high-performance organic solar cells (OSCs). Herein, a series of non-fullerene acceptor (NFA) molecules with A-D-A structures, TTCn-4F, with gradient substituent lengths of terminal side chains (T-SCs) on the molecular backbones have been designed and synthesized. The effects of T-SCs length, ranging from hydrogen atom to n-dodecyl, their optoelectronic properties, thin film molecular packing, blend film morphology, and overall photovoltaic performance have been systematically studied. The results show that among this series of molecules, TTC8-4F with n-octyl substituent, showed the best photovoltaic performance when applied with PM6 as the donor due to its favorable morphology, balanced charge mobility, effective exciton dissociation and less charge recombination. Based on this, its ternary device with F-Br as the secondary acceptor achieved a high PCE of 15.34% with the simultaneously enhanced V_oc of 0.938 V, J_sc of 22.66 mA cm⁻², and FF of 72.15%. These results indicate that the engineering of T-SCs is an effective strategy for designing high-performance NFAs.

侧链工程对于高性能有机太阳能电池（OSC）发挥着重要作用。本文中，已经设计并合成了一系列具有ADA结构的非富勒烯受体（NFA）分子TTCn-4F，在分子主链上具有末端侧链（T-SCs）的梯度取代基长度。已经系统地研究了从氢原子到正十二烷基的T-SCs长度的影响，它们的光电性能，薄膜分子堆积，共混膜形态和整体光伏性能。结果表明，在这一系列分子中，具有正辛基取代基的TTC8-4F由于以其良好的形貌，平衡的电荷迁移率，有效的激子离解和较少的电荷重组而当以PM6作为施主时显示出最佳的光伏性能。基于此，V _oc为0.938 V，J _sc为22.66 mA cm ^-2，FF为72.15％。这些结果表明，T-SC的工程设计是设计高性能NFA的有效策略。