During the long history of organic solar cells (OSCs), many excellent building blocks have emerged for the construction of high-performance electron donor/acceptor materials. Among them, the 4H-cyclopenta[2,1-b:3,4-b′]dithiophene (CPDT) unit was popular in the fullerene era, but declined in the early stage of the nonfullerene era. Recently, CPDT has experienced a revival with the emergence of low-cost nonfused-ring electron acceptors (NFREAs). This review aims to provide an overview of the structural isomers, photoelectric properties, and synthesis progress of the CPDT unit. Subsequently, the development of CPDT-based materials in the past few decades is summarized and discussed, including polymer donors for fullerene-based OSCs, NFREAs and polymerized NFREAs for nonfullerene-based OSCs.

中文翻译：

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低成本高性能非稠环电子受体驱动4H-环戊[2,1-b:3,4-b']二噻吩（CPDT）的复兴


在有机太阳能电池（OSC）的悠久历史中，出现了许多用于构建高性能电子供体/受体材料的优秀构件。其中，4H-环戊[2,1-b:3,4-b']二噻吩（CPDT）单元在富勒烯时代很流行，但在非富勒烯时代早期逐渐衰落。最近，随着低成本非稠环电子受体（NFREA）的出现，CPDT 经历了复兴。本综述旨在概述CPDT单元的结构异构体、光电性能和合成进展。随后，总结和讨论了过去几十年来基于CPDT的材料的发展，包括用于富勒烯基OSC的聚合物供体、NFREA和用于非富勒烯基OSC的聚合NFREA。