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Branched Terminal Alkyl Chain Enabling 15.7% Efficiency Oligothiophene Donor
Chen, Qianqian1,2; Li, Yulu2; Hu, Dingqin1,2; Lu, Shirong3; Xiao, Zeyun2
2023-11-23
摘要Optimizing the alkyl chains in a terminal group is one of the most efficient strategies to enhance the power conversion efficiency (PCE) of all small molecule organic solar cells (ASM-OSCs). Oligothiophene, as an easily synthesized small molecule (SM) donor with an explicit structure, can influence intermolecular packing, planarity, and crystallinity through optimization of the alkyl chain in the terminal group. Herein, two SMs, Tz6T-P and Tz6T-iP, are synthesized using the n-propyl and isopropyl isomers, respectively, as alkyl chains in the terminal group. Compared with the linear chain (n-propyl) of Tz6T-P, the rigid branch chain (isopropyl) in Tz6T-iP exhibits an almost complanate configuration in the ground state and higher crystallinity. Consequently, Tz6T-iP features lower levels of bimolecular recombination and trap-assisted recombination, higher ability for exciton dissociation and charge collection, and longer carrier lifetimes. Tz6T-iP achieves a PCE of 15.7% for oligothiophene-based ASM-OSCs. These results provide innovative strategies, demonstrating that branching the terminal alkyl chain can adjust planarity, crystallinity, and separation morphology for the structural design of photovoltaic materials. Two oligothiophene-based small molecule donors, Tz6T-P and Tz6T-iP, are designed and synthesized. The isopropyl group-functionalized Tz6T-iP provides lower levels of bimolecular recombination and trap-assisted recombination, and enables a higher ability for exciton dissociation and longer carrier lifetime in all small molecule organic solar cells.image (c) 2023 WILEY-VCH GmbH
关键词oligothiophene donors organic solar cells small molecule donors terminal alkyl chains
DOI10.1002/solr.202300802
发表期刊SOLAR RRL
ISSN2367-198X
页码8
通讯作者Hu, Dingqin(hudingqing@cijit.ac.cn) ; Lu, Shirong(lushirong@cigit.ac.cn) ; Xiao, Zeyun(xiao.z@cigit.ac.cn)
收录类别SCI
WOS记录号WOS:001106818500001
语种英语