title: Fused Nonacyclic Electron Acceptors for Efficient Polymer Solar Cells.
abstract: We design and synthesize four fused-ring electron acceptors based on 6,6,12,12-tetrakis(4-hexylphenyl)-indacenobis(dithieno[3,2-b;2',3'-d]thiophene) as the electron-rich unit and 1,1-dicyanomethylene-3-indanones with 0-2 fluorine substituents as the electron-deficient units. These four molecules exhibit broad (550-850 nm) and strong absorption with high extinction coefficients of (2.1-2.5) × 105M-1cm-1. Fluorine substitution downshifts the LUMO energy level, red-shifts the absorption spectrum, and enhances electron mobility. The polymer solar cells based on the fluorinated electron acceptors exhibit power conversion efficiencies as high as 11.5%, much higher than that of their nonfluorinated counterpart (7.7%). We investigate the effects of the fluorine atom number and position on electronic properties, charge transport, film morphology, and photovoltaic properties.
authors.affiliation: Department of Materials Science and Engineering, College of Engineering, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Peking University , Beijing 100871, China.|Fujian Key Laboratory of Polymer Materials, College of Materials Science and Engineering, Fujian Normal University , Fuzhou 350007, China.
authors.forename: Shuixing
authors.initials: S
authors.lastname: Dai
authors.affiliation: Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China.
authors.forename: Fuwen
authors.initials: F
authors.lastname: Zhao
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States.
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Department of Physics, Chinese University of Hong Kong , New Territories, Hong Kong, China.
authors.forename: Tsz-Ki
authors.initials: TK
authors.lastname: Lau
authors.affiliation: Department of Materials Science and Engineering, College of Engineering, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Peking University , Beijing 100871, China.
authors.forename: Tengfei
authors.initials: T
authors.lastname: Li
authors.affiliation: Department of Materials Science and Engineering, College of Engineering, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Peking University , Beijing 100871, China.
authors.forename: Kuan
authors.initials: K
authors.lastname: Liu
authors.affiliation: Fujian Key Laboratory of Polymer Materials, College of Materials Science and Engineering, Fujian Normal University , Fuzhou 350007, China.
authors.forename: Qidan
authors.initials: Q
authors.lastname: Ling
authors.affiliation: Institute of Chemistry, Chinese Academy of Sciences , Beijing 100190, China.
authors.forename: Chunru
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Physics, Chinese University of Hong Kong , New Territories, Hong Kong, China.
authors.forename: Xinhui
authors.initials: X
authors.lastname: Lu
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States.
authors.forename: Wei
authors.initials: W
authors.lastname: You
authors.affiliation: Department of Materials Science and Engineering, College of Engineering, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, Peking University , Beijing 100871, China.
authors.forename: Xiaowei
authors.identifier: 0000-0002-1006-3342
authors.initials: X
authors.lastname: Zhan