Three novel benzodipyrrolinone–bithiophene based donor-acceptor polymers are synthesized and used as p-type semiconductors in organic thin-film transistors (OTFTs). Hole mobility of up to 0.03 cm2 V−1 s−1 is achieved. A new acetal-type branched substituent is introduced to significantly improve the solubility of the resulting polymer.
N-acylation was studied as a method for reducing the LUMO energy levels of benzodipyrrolidone-based polymers. The N-acylated polymers showed reduced LUMO levels and improved reversibility of reductive doping compared with N-alkylated polymers. This method may also apply in other conjugated polymers with lactam repeating units.