Isomers with small structural changes usually exhibit different properties. Rationally designing isomers of some high-performance SMAs can further enhance their function. In this work, an asymmetrical small molecule acceptor (SMA) MeIC1 isomerized from MeIC is reported. Compared with the symmetrical MeIC, the asymmetrical isomer showed almost the same absorption range but an elevated LUMO energy level and simultaneously enhanced π–π stacking and electron mobility by replacing the thieno[3,2-b]thiophene unit with a larger sized dithieno[3,2-b:2′,3′-d]thiophene unit in the ladder-type core of MeIC. As a result, the MeIC1-based PSCs achieved a higher PCE up to 12.58% with a promoted V_oc and J_sc and an unchanged FF compared with those of MeIC-based PSCs when blended with PBDB-T. This work reveals that asymmetrical isomerization is effective for PCE promotion.

中文翻译：

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设计一种不对称异构体以提高聚合物太阳能电池非富勒烯受体的 LUMO 能级和分子堆积，效率为 12.6%†

结构变化较小的异构体通常表现出不同的性质。合理设计一些高性能SMA的异构体可以进一步增强其功能。在这项工作中，报道了由 MeIC 异构化的不对称小分子受体 (SMA) MeIC1。与对称MeIC相比，不对称异构体表现出几乎相同的吸收范围，但通过用更大尺寸的二噻吩并取代噻吩并[3,2- b ]噻吩单元，提高了LUMO能级，同时增强了π-π堆积和电子迁移率。MeIC 梯型核心中的3,2- b :2′,3′- d ]噻吩单元。结果，与基于 MeIC 的 PSC 与PBDB-T 混合时相比，基于 MeIC1 的 PSC实现了高达 12.58% 的更高 PCE，并且V _oc和J _{sc有所提高，FF 没有变化。}这项工作表明，不对称异构化对于促进 PCE 是有效的。