Tailorable PC₇₁BM Isomers: Using the Most Prevalent Electron Acceptor to Obtain High-Performance Polymer Solar Cells

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• 作者：Xin-Xing Zhan ; Xin Zhang ; Si-Min Dai ; Shu-Hui Li ; Xu-Zhai Lu ; Dr. Lin-Long Deng ; Prof. Su-Yuan Xie ; Prof. Rong-Bin Huang and Prof. Lan-Sun Zheng
• 刊名：Chemistry - A European Journal
• 出版年：2016
• 出版时间：December 23, 2016
• 年：2016
• 卷：22
• 期：52
• 页码：18709-18713
• 全文大小：2658K
• ISSN：1521-3765

文摘

Despite being widely used as electron acceptor in polymer solar cells, commercially available PC₇₁BM (phenyl-C₇₁-butyric acid methyl ester) usually has a “random” composition of mixed regioisomers or stereoisomers. Here PC₇₁BM has been isolated into three typical isomers, α-, β₁- and β₂-PC₇₁BM, to establish the isomer-dependent photovoltaic performance on changing the ternary composition of α-, β₁- and β₂-PC₇₁BM. Mixing the isomers in a ratio of α/β₁/β₂=8:1:1 resulted in the best power conversion efficiency (PCE) of 7.67 % for the polymer solar cells with PTB7:PC₇₁BM as photoactive layer (PTB7=poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]]). The three typical PC₇₁BM isomers, even though sharing similar LUMO energy levels and light absorption, render starkly different photovoltaic performances with average-performing PCE of 1.28–7.44 % due to diverse self-aggregation of individual or mixed PC₇₁BM isomers in the otherwise same polymer solar cells.