Abstract

The end groups of small-molecule acceptors strongly affect their properties and performance. In this study, theoretical analysis is performed to determine the reason why two similar molecules differing in their end group show very different performance in organic solar cells. The 1,1-dicyanomethylene-3-indanone-based small-molecule acceptor (DC-IDT2Tz) shows a higher transition dipole moment as compared with the rhodanine-based small acceptor (RD-IDT2Tz). DC-IDT2Tz presents a lower exciton binding energy as compared with RD-IDT2Tz. Moreover, DC-IDT2Tz shows a lower reorganization energy and higher transfer integrals than RD-IDT2Tz. All these theoretical descriptors can explain the reason behind the higher efficiency of DC-IDT2Tz. The studied theoretical parameters can help to verify the performance of organic semiconductors before synthesis. This work will thus be helpful for experimental scientists to screen compounds and select the best one for synthesis.

Graphic abstract

中文翻译：

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计算分析以了解两个小分子受体在其末端电子不足基团不同的性能差异

摘要

小分子受体的端基强烈影响其性能和性能。在这项研究中，进行了理论分析，以确定为什么两个相似的分子在其端基不同的原因在有机太阳能电池中显示出非常不同的性能。1，1-二氰基亚甲基-3-茚满酮基小分子受体（DC-IDT2Tz）与基于罗丹宁的小受体（RD-IDT2Tz）相比，具有更高的跃迁偶极矩。与RD-IDT2Tz相比，DC-IDT2Tz的激子结合能更低。此外，与RD-IDT2Tz相比，DC-IDT2Tz显示出更低的重组能量和更高的转移积分。所有这些理论描述符都可以解释DC-IDT2Tz效率更高的原因。研究的理论参数可以帮助验证合成前有机半导体的性能。

图形摘要