Single junction binary all‐small‐molecule (ASM) organic solar cells (OSCs) with power conversion efficiency (PCE) beyond 14% are achieved by using non‐fullerene acceptor Y6 as the electron acceptor, but still lag behind that of polymer OSCs. Herein, an asymmetric Y6‐like acceptor, BTP‐FCl‐FCl, is designed and synthesized to match the recently reported high performance small molecule donor BTR‐Cl, and a record efficiency of 15.3% for single‐junction binary ASM OSCs is achieved. BTP‐FCl‐FCl features a F,Cl disubstitution on the same end group affording locally asymmetric structures, and so has a lower total dipole moment, larger average electronic static potential, and lower distribution disorder than those of the globally asymmetric isomer BTP‐2F‐2Cl, resulting in improved charge generation and extraction. In addition, BTP‐FCl‐FCl based active layer presents more favorable domain size and finer phase separation contributing to the faster charge extraction, longer charge carrier lifetime, and much lower recombination rate. Therefore, compared with BTP‐2F‐2Cl, BTP‐FCl‐FCl based devices provide better performance with FF enhanced from 71.41% to 75.36% and J_sc increased from 22.35 to 24.58 mA cm⁻², leading to a higher PCE of 15.3%. The locally asymmetric F, Cl disubstitution on the same end group is a new strategy to achieve high performance ASM OSCs.

中文翻译：

---

通过局部非对称F，Cl取代策略获得的效率为15.3％的全小分子有机太阳能电池

通过使用非富勒烯受体Y6作为电子受体来实现功率转换效率（PCE）超过14％的单结二元全小分子（ASM）有机太阳能电池（OSC），但仍落后于聚合物OSC。本文设计并合成了一种不对称的类似Y6的受体BTP-FCl-FC1，以匹配最近报道的高性能小分子供体BTR-Cl，单结二元ASM OSC的记录效率达到了15.3％的创纪录水平。BTP-FCl-FC1在同一端基上具有F，Cl分解的特征，提供局部不对称结构，因此与全局不对称异构体BTP-2F相比，总偶极矩更低，平均电子静电势更大且分布紊乱性更低‐2Cl，可改善电荷的产生和提取。此外，基于BTP-FCl-FCI的有源层呈现出更有利的畴尺寸和更精细的相分离，从而有助于更快的电荷提取，更长的载流子寿命和更低的重组率。因此，与BTP-2F-2Cl相比，基于BTP-FCl-FCI的设备可提供更好的性能，且FF从71.41％增强到75.36％，而J _sc从22.35 mA cm ^-2增加到24.58 mA cm ^-2，导致PCE升高15.3％。同一端基上的局部不对称F，Cl破坏是实现高性能ASM OSC的新策略。