Donor-acceptor-donor molecules based on diketopyrrolopyrrole, benzodipyrrolidone and naphthodipyrrolidone: Organic crystal field-effect transistors

Three π-conjugated large organic molecules based on diketopyrrolopyrrole (DPP), benzodipyrrolidone (BDP) and naphthodipyrrolidone (NDP) are synthesized and characterized. By introducing bi-thiophene units at the end of DPP/BDP/NDP chromophores, the molecules are able to form a donor–acceptor–donor (D-A-D) system. All of them exhibit high thermal stability, strong aggregation, high values in highest occupied and low values in lowest unoccupied molecular orbital (HOMO/LUMO) energy levels. In this work, a simple solution process technique for large organic molecules crystal organic field-effect transistors (OFETs) is used to fabricate devices. DPP- and BDP-based large organic molecular crystals exhibit p-type behavior with hole mobility of 0.02 cm2 V−1 s−1 and 0.09 cm2 V−1 s−1, while large organic molecular crystal based on NDP shows n-type behavior with electron mobility up to 0.26 cm2 V−1 s−1. This work demonstrated that extension of the π-conjugation system is a useful strategy to build high charge mobility materials. In addition, BDP is an interesting electron-withdrawing block for p-type semiconductor while NDP is a promising chromophore for the construction of n-type high-performance OFETs.