Molecular Engineering of Nonhalogenated Solution-Processable Bithiazole-Based Electron-Transport Polymeric Semiconductors

Abstract

The electron deficiency and trans-planar conformation of bithiazole is potentially beneficial for the electron-transport performance of organic semiconductors. However, the incorporation of bithiazole into polymers through a facile synthetic strategy remains a challenge. Herein, 2,2′-bithiazole was synthesized in one step and copolymerized with dithienyldiketopyrrolopyrrole to afford poly(dithienyldiketopyrrolopyrrole-bithiazole), PDBTz. PDBTz exhibited electron mobility reaching 0.3 cm2 V–1 s–1 in organic field-effect transistor (OFET) configuration; this contrasts with a recently discussed isoelectronic conjugated polymer comprising an electron-rich bithiophene and dithienyldiketopyrrolopyrrole, which displays merely hole-transport characteristics. This inversion of charge-carrier transport characteristics confirms the significant potential for bithiazole in the development of electron-transport semiconducting materials. Branched 5-decylheptacyl side chains were incorporated into PDBTz to enhance polyme...