A vinyl flanked difluorobenzothiadiazole–dithiophene conjugated polymer for high performance organic field-effect transistors

Abstract

Fluorine containing conjugated polymers have been widely applied in high performance organic solar cells, but their use in field-effect transistors is still quite limited. In this work, a conjugated polymer PTFBTV based on difluorobenzothiadiazole (DFBT) and dithiophene was synthesized, utilizing multiple vinylene as linkers. The polymer exhibits a relatively high hole mobility up to 2.0 cm² V⁻¹ s⁻¹ compared with the reported DFBT–oligothiophene based polymers, yet its structural complexity is much simpler. The polymer thin film exhibits a typical ‘face on’ molecular orientation. A single crystal of its monomer revealed a non-covalent intramolecular contact between fluorine and the neighbouring proton, which strengthens the backbone co-planarity. Meanwhile an intermolecular F⋯F contact was also observed, which might cause rather scattered lamellar crystallinity for PTFBTV in the solid state.