Diketopyrrolopyrrole-based conjugated polymer for printed organic field-effect transistors and gas sensors

Abstract

We synthesize a diketopyrrolopyrrole (DPP)-based conjugated polymer (LGC-D148) that includes thiophene and difluorophenylenedithiophene as donors for the active layer of solution processable organic field-effect transistors (OFETs) and printed ammonia gas sensors. Typical ambipolar characteristics with reasonably high field-effect mobility (μFET) of 0.48 ± 0.12 cm2/V s for the holes and μFET of 0.079 ± 0.02 cm2/V s for the electrons are achieved by optimizing the top-gate bottom-contact OFETs. The LGC-D148 OFETs show a reliable and reversible gas sensing property upon exposure to ammonia gas. Specifically, a high sensitivity of over 90% is attained upon exposure to 1000 ppm ammonia gas, by a repeatable and gradual negative shift in the transfer curves.