Abstract A halogen-free solvent 1,2,4-trimethylbenzene dissolves both unmodified fullerenes and conjugated polymers such as PTB7-Th. This unique feature enables the study on the effect of the substituent of fullerene in polymer:fullerene bulk heterojunction solar cells under low-light illumination. Although the power conversion efficiency (PCE) of the PTB7-Th:C70 solar cell was higher than that of the PTB7-Th:C70-PCBM solar cell under one sun illumination, the latter showed higher PCE than the former under 10−3 sun illumination. This result comes from the fact that C70-PCBM yields higher open-circuit voltage (VOC) at one sun and smaller dependence of VOC on illumination light intensity than C70.

中文翻译：

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富勒烯取代基对聚合物微光特性的影响：富勒烯本体异质结太阳能电池

摘要 无卤溶剂 1,2,4-三甲苯可溶解未改性的富勒烯和共轭聚合物，如 PTB7-Th。这种独特的特性使研究富勒烯取代基在聚合物：富勒烯本体异质结太阳能电池中在低光照条件下的影响成为可能。虽然PTB7-Th:C70太阳能电池在一次阳光照射下的功率转换效率（PCE）高于PTB7-Th:C70-PCBM太阳能电池，但后者在10-3阳光下表现出高于前者的PCE照明。这一结果来自这样一个事实：与 C70 相比，C70-PCBM 在一个太阳下产生更高的开路电压 (VOC) 并且 VOC 对照明光强度的依赖性更小。