Synthesis, photophysics and photovoltaics of alternating vinylene-copolymer and model compound containing triphenylamine moieties along the backbone

A soluble alternating vinylene-copolymer P and the corresponding model compound M were synthesized by Heck coupling. They contained triphenylamine moieties and cyano-substituted olefinic bonds along the backbone. Both samples were stable up to about 300 °C and afforded char yields of 76–89% at 800 °C. Their glass transition temperature (Tg) was 72–78 °C and the absorption maximum was located at 307–366 nm with optical band gaps of 2.19–2.35 eV. They emitted yellow-orange light with photoluminescence (PL) maximum at 560–576 nm. Bulk heterojunction photovoltaic cells with the configuration of ITO/PEDOT:PSS/Sample:PCBM(1:1, w/w)/LiF/Al were fabricated. The PCE of devices based on P and M reached 0.09% and 0.07%, respectively.