Two β-cyano-thiophenevinylene-based polymers containing cyclopentadithiophene (CPDT-CN) and dithienosilole (DTS-CN) units were synthesized via Stille coupling reaction with Pd(PPh3)4 as a catalyst. The effects of the bridged atoms (C and Si) and cyano-vinylene groups on their thermal, optical, electrochemical, charge transporting, and photovoltaic properties were investigated. Both polymers possessed the highest occupied molecular orbital (HOMO) levels of about -5.30 eV and the lowest unoccupied molecular orbital (LUMO) levels of about -3.60 eV, and covered broad absorption ranges with narrow optical band gaps (ca. 1.6 eV). The bulk heterojunction polymer solar cell (PSC) devices containing an active layer of electron-donor polymers (CPDT-CN and DTS-CN) blended with an electron-acceptor, that is, [6,6]-phenyl-C61-butyric acid methyl ester (PC 61BM) or [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM), in different weight ratios were explored under 100 mW/cm2 of AM 1.5 white-light illumination. The PSC device based on DTS-CN:PC71BM (1:2 w/w) exhibited a best power conversion efficiency (PCE) value of 2.25% with Voc = 0.74 V, Jsc = 8.39 mA/cm2, and FF = 0.36.
|Number of pages||9|
|Journal||Journal of Polymer Science, Part A: Polymer Chemistry|
|State||Published - 1 Aug 2011|
- conjugated polymers
- heteroatom-containing polymers
- solar cells