Absorption-enhanced polymer solar cells based on broad band-gap poly(triphenylamine-alt-benzo[c][1,2,5]selenadiazole) derivative

•The introduction of benzo[c][1,2,5]selenadiazole decreases the band gap notably.•The PTPADTSe shows the optical band gap of 1.90 eV.•The PTPADTSe based polymer solar cell gives the open circuit voltage of 0.81 V.

A triphenylamine and benzo[c][1,2,5]selenadiazole based broad band-gap polymer PTPADTSe was synthesized by Suzuki polycondensation. The thermal, photophysical, electrochemical, and photovoltaic properties were characterized in detail. The polymer showed a high thermal stability with the decomposition temperature at 377 °C. The absorption peaks of PTPADTSe in film were located at 359 and 561 nm with the optical bang gap of 1.84 eV. Through the cyclic voltammogram measurement, it gave the highest occupied molecular orbit (HOMO) energy level of −5.14 eV. The polymer solar cell was fabricated under the device structure of ITO/PSS:PEDOT/PTPADTSe: PC61BM/LiF/Al, where it displayed the photovoltaic performance with the short circuit current density (Jsc) of 1.32 mA cm−2, open circuit voltage (Voc) of 0.81 V, fill factor (FF) of 35% and power conversion efficiency (PCE) of 0.52%, respectively.