Side-Substituent Assisted Ordered Structures of A Benzodithiophene and Diketopyrrolopyrrole-based copolymer

초록

A π-conjugated donor-acceptor copolymer containing alternated triisopropylsilylethynyl (TIPS)-benzodithiophene (BDT) and diketopyrrolopyrrole (DPP), such as donor (D) and acceptor (A) blocks, respectively, was synthesized to enhance the intermolecular interaction between the conjugated D-A backbone, and its electrical properties in organic field-effect transistors (OFETs) were compared to those of the control BDT-DPP copolymer with a similar molecular weight but no TIPS substituent. On the benefit of the bulky TIPS side-substituents onto the BDT block, the TIPSBDT-DPP based copolymer formed highly ordered domains even in spun-cast films, and further developed a long-range π-overlapped layer after thermal annealing. Optimized TIPSBDT-DPP annealed films showed high field-effect mobility values of up to 0.5 cm2V-1s-1 in OFETs.