title: Tailorable PC71BM Isomers: Using the Most Prevalent Electron Acceptor to Obtain High-Performance Polymer Solar Cells.
abstract: 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.
authors.affiliation: Department of Chemistry, College of Chemistry and Chemical Engineering, State Key Laboratory for Physical Chemistry of Solid Surfaces, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Xiamen University, Xiamen, 361005, P.R. China.|School of Guizhou Normal University, Guiyang, 550001, P.R. China.
authors.forename: Xin-Xing
authors.initials: XX
authors.lastname: Zhan
authors.affiliation: Department of Chemistry, College of Chemistry and Chemical Engineering, State Key Laboratory for Physical Chemistry of Solid Surfaces, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Xiamen University, Xiamen, 361005, P.R. China.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, College of Chemistry and Chemical Engineering, State Key Laboratory for Physical Chemistry of Solid Surfaces, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Xiamen University, Xiamen, 361005, P.R. China.
authors.forename: Si-Min
authors.initials: SM
authors.lastname: Dai
authors.affiliation: Department of Chemistry, College of Chemistry and Chemical Engineering, State Key Laboratory for Physical Chemistry of Solid Surfaces, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Xiamen University, Xiamen, 361005, P.R. China.
authors.forename: Shu-Hui
authors.initials: SH
authors.lastname: Li
authors.affiliation: Department of Chemistry, College of Chemistry and Chemical Engineering, State Key Laboratory for Physical Chemistry of Solid Surfaces, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Xiamen University, Xiamen, 361005, P.R. China.
authors.forename: Xu-Zhai
authors.initials: XZ
authors.lastname: Lu
authors.affiliation: Pen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University, Xiamen, 361005, P.R. China.
authors.forename: Lin-Long
authors.initials: LL
authors.lastname: Deng
authors.affiliation: Department of Chemistry, College of Chemistry and Chemical Engineering, State Key Laboratory for Physical Chemistry of Solid Surfaces, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Xiamen University, Xiamen, 361005, P.R. China.
authors.forename: Su-Yuan
authors.initials: SY
authors.lastname: Xie
authors.affiliation: Department of Chemistry, College of Chemistry and Chemical Engineering, State Key Laboratory for Physical Chemistry of Solid Surfaces, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Xiamen University, Xiamen, 361005, P.R. China.
authors.forename: Rong-Bin
authors.initials: RB
authors.lastname: Huang
authors.affiliation: Department of Chemistry, College of Chemistry and Chemical Engineering, State Key Laboratory for Physical Chemistry of Solid Surfaces, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Xiamen University, Xiamen, 361005, P.R. China.
authors.forename: Lan-Sun
authors.initials: LS
authors.lastname: Zheng
keywords: electron acceptors; fullerenes; isomers; phase diagrams; polymer solar cells