High performance nitrogen dioxide sensor based on organic field-effect transistor utilizing ultrathin CuPc/PTCDI-C8 heterojunction

Organic field-effect transistors (OFETs) with a heterojunction structure, consisting of the p-type and n-type organic semiconducting materials of copper phthalocyanine (CuPc) and the dioctyl perylene tetracarboxylic diimide (PTCDI-C8), respectively, were fabricated. The heterojunction OFETs were used as the nitrogen dioxide (NO2) gas sensors, and the sensing properties were characterized with the variation of PTCDI-C8 layer thicknesses. The results showed that the OFET sensors with the optimized film thickness of 0.5 nm PTCDI-C8 and 7 nm CuPc, had one order of magnitude enhancement of sensitivity, compared to the device with single CuPc active layer. The sensitivity improvement was attributed to the intensification of the charge transfer in the heterojunction structure while introducing the oxidizing gas of NO2. (C) 2015 Elsevier B.V. All rights reserved.