High-efficiency all-small-molecule organic solar cells based on an organic molecule donor with an asymmetric thieno[2,3-f]benzofuran unit

• 来源期刊: 中国科学：化学（英文版）
• 年，卷（期）: 2020,（9）
• 所属期刊栏目: ARTICLES
• 页码范围: 1246-1255
• 页数: 10页
• 语种: 英文

摘要

Two p-type small molecules BDTT-TR and TBFT-TR with benzo[1,2-b':4,5-b']dithiophene (BDT) and thieno[2,3-f]benzofuran (TBF) as central core units are synthesized and used as donors in all-small-molecule organic solar cells (all-SMOSCs) with a narrow-bandgap small molecule Y6 (2,2'-((2Z,2'Z)-((12,13-bis(2-ethylhexyl)-3,9-diundecyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2",3":4',5qthieno[2',3': 4,5]pyrrolo[3,2-g]thieno[2',3':4,5]thieno[3,2-b]indole-2,10-diyl)bis(methanylylidene))bis (5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile) as the acceptor.In comparison to BDTT-TR with centrosymmetric BDT as the central unit,TBFT-TR with asymmetric TBF as the central unit shows red-shifted absorption,higher charge-carrier mobility and better charge pathway in blend films.The power conversion efficiency (PCE) of the all-SMOSCs based on TBFT-TR:Y6 reaches 14.03％ with a higher short-circuit current density of 24.59 mA cm-2 and a higher fill factor of 72.78％ compared to the BDTT-TR:Y6 system.The PCE of 14.03％ is among the top efficiencies ofall-SMOSCs reported in the literature to date.