Synthesis and Photovoltaic Properties of Thieno[3,4-b]pyrazine or Dithieno[3′,2′:3,4;2",3":5,6]benzo[1,2-d]imidazole-Containing Conjugated Polymers

Novel conjugated polymers composed of benzo[1,2-b:4,5-b]dithiophene and thieno[3,4-b]pyrazine or dithieno[3,2:3,4;2,3:5,6]benzo[1,2-d]imidazole units are synthesized by Stille polycondensation. The resulting polymers display a longer wavelength absorption and well-defined redox activities. The effective intramolecular charge-transfer and energy levels of all polymers are elucidated by computational calculations. Bulk-heterojunction solar cells based on these polymers as p-type semiconductors and [6,6]-phenyl-C-61-butyric acid methyl ester (PC61BM) as an n-type semiconductor are fabricated, and their photovoltaic performances are for the first time evaluated. (c) 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1067-1075