Ambipolar charge transport in a donor-acceptor-donor-type conjugated block copolymer and its gate-voltage-controlled thin film transistor memory

Abstract

We demonstrate a fully conjugated donor-acceptor-donor (D-A-D) triblock copolymer, PBDTT-PNDIBT-PBDTT, which contains PBDTT as the donor block and PNDIBT as the acceptor block. The polymer was synthesized by end-capping each block with a reactive unit, followed by condensation copolymerization between the two blocks. The physical, optical, and electrochemical properties of the polymer were investigated by comparing those of donor- and acceptor-homopolymers (i.e., PBDTT and PNDIBT), which are the oligomeric monomers, and their blends. On using the newly synthesized block copolymer, ambipolar charge transport behavior was observed in the corresponding thin-film transistor, and the behavior was compared to that of blend film of donor- and acceptor-homopolymers. Owing to the presence of donor and acceptor blocks in a single polymer chain, it was found that the triblock copolymer can store two-level information; the ability to store this information is one of the most intriguing challenges in memory applications. In this study, we confirmed the potential of the triblock copolymer in achieving distinct two-stage data storage by utilizing the ambipolar charge trapping phenomenon, which is expected in donor and acceptor containing random and block copolymers in a thin-film transistor. (c) 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 3223-3235