Power conversion efficiency (PCE) of organic solar cells (OSCs) processed by nonhalogenated solvents is unsatisfactory due to the unfavorable morphology. Herein, two new small molecule acceptors (SMAs) Y6-Ph and L8-Ph are synthesized by introducing a phenyl end group in the inner side chains of the SMAs of Y6 and L8-BO, respectively, for overcoming the excessive aggregation of SMAs in the long-time film forming processed by nonhalogenated solvents. First, the effect of the film forming time on the aggregation property and photovoltaic performance of Y6, L8-BO, Y6-Ph, and L8-Ph is studied by using the commonly used solvents: chloroform (CF) (rapid film forming process) and chlorobenzene (CB) (slow film forming process). It is found that Y6- and L8-BO-based OSCs exhibit a dramatic drop in PCE from CF- to CB-processed devices owing to the large phase separation, while the Y6-Ph and L8-Ph based OSCs show obviously increased PCEs Furthermore, L8-Ph-based OSCs processed by nonhalogenated solvent o-xylene (o-XY) achieved a high PCE of 18.40% with an FF of 80.11%. The results indicate that introducing a phenyl end group in the inner side chains is an effective strategy to modulate the morphology and improve the photovoltaic performance of the OSCs processed by nonhalogenated solvents.中文翻译：
在 A-DA'DA 受体的内侧侧链中引入苯基端基可实现使用非卤化溶剂处理的高效有机太阳能电池采用非卤化溶剂加工的有机太阳能电池（OSC）由于形貌不佳，其功率转换效率（PCE）并不令人满意。在此，通过分别在Y6和L8-BO的SMA的内侧链上引入苯基端基，合成了两种新的小分子受体（SMA）Y6-Ph和L8-Ph，以克服SMA在中的过度聚集。采用非卤化溶剂长时间成膜。首先，利用常用溶剂：氯仿（CF）（快速成膜工艺），研究了成膜时间对Y6、L8-BO、Y6-Ph、L8-Ph的聚集性能和光伏性能的影响。和氯苯（CB）（慢速成膜过程）。研究发现，由于相分离较大，基于 Y6 和 L8-BO 的 OSC 从 CF 加工到 CB 加工的器件中 PCE 急剧下降，而基于 Y6-Ph 和 L8-Ph 的 OSC 则表现出明显增加的 PCE。由非卤化溶剂邻二甲苯（o -XY）加工的L8-Ph基OSC实现了18.40%的高PCE和80.11%的FF。结果表明，在内侧链中引入苯基端基是调节非卤化溶剂加工的有机太阳能电池的形貌和提高其光伏性能的有效策略。