New conjugated regular terpolymers based on diketopyrrolopyrrole-benzodithiophene and their application to thin film transistors and polymer solar cells

•DPP–based conjugated regular terpolymers containing two different electron donor monomers were synthesized.•Compared to PDPPBDT, the new terpolymers exhibited distinct absorption properties, and electronic energy levels.•The highest mobility in PDPPBTBDT-based TFT devices was close to 1.0 cm2 V−1 s−1.•The PSC fabricated with PDPPPYBDT:PC71BM showed the highest PCE of 4.46% due to the relatively high Voc and Jsc.