Synthesis and photovoltaic properties of conjugated copolymers with benzo[1,2-b:4,5-b′]dithiophene and thiadiazolo[3,4-c]pyridine moieties

Three conjugated copolymers containing thiadiazolo[3,4-c]pyridine as electron- withdrawing unit were synthesized. The introduction of thiadiazolo[3,4-c]pyridine led to enhanced π-π stacking of the polymer in film and an unexpected non-ohmic contact on the interface of the polymer and hole extraction layer. PBDTT-T-DTPyT exhibited a high hole mobility of 1.2 × 10−2 cm2 V−1 S−1.