title: Thiophene fluorination to enhance photovoltaic performance in low band gap donor-acceptor polymers.
abstract: We report the first synthesis of a tetrafluorinated 4,7-bis(3,4-difluorothiophen-2-yl)-2,1,3-benzothiadiazole monomer and its polymerisation with dithieno[3,2-b:2',3'-d]germole by Stille coupling to afford a low band gap polymer with a high ionisation potential. Direct comparison to the non-fluorinated analogue demonstrates that fluorination results in an increase in ionisation potential with no change in optical band gap, and enhanced aggregation over the non-fluorinated polymer. These desirable properties result in a significant enhancement in OPV device performance in blends with PC(71)BM.
authors.affiliation: Dept. Chemistry and Centre for Plastic Electronics, Imperial College London, London SW7 2AZ, UK.
authors.forename: Zhuping
authors.initials: Z
authors.lastname: Fei
authors.forename: Munazza
authors.initials: M
authors.lastname: Shahid
authors.forename: Nir
authors.initials: N
authors.lastname: Yaacobi-Gross
authors.forename: Stephan
authors.initials: S
authors.lastname: Rossbauer
authors.forename: Hongliang
authors.initials: H
authors.lastname: Zhong
authors.forename: Scott E
authors.initials: SE
authors.lastname: Watkins
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Anthopoulos
authors.forename: Martin
authors.initials: M
authors.lastname: Heeney
mesh_terms: D054879:Halogenation; D011108:Polymers / Q000737:chemistry*; D011789:Quantum Theory; D012993:Solar Energy; D013830:Thiadiazoles / Q000737:chemistry; D013876:Thiophenes / Q000737:chemistry*
chemical_list: D011108:Polymers; D013830:Thiadiazoles; D013876:Thiophenes; C015700:benzo-1,2,3-thiadiazole