Organic field-effect transistors (OFETs) with a heterojunction structure were fabricated and the relationship between the performance characteristics with copper phthalocyanine (CuPc) and the dioctyl perylene tetracarboxylic diimide (PTCDI-C8) heterojunctions and the thickness of the PTCDI-C8 layer is investigated. The changes of the electrical parameter are attributable to the morphology of the film and the heterojunction effect. Moreover, 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, compared to the device with single CuPc active layer, 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, enabling a detection limitation of NO2 as low as 2 ppm. The sensitivity enhancement was attributed to the intensification of the charge transfer in the heterojunction structure while introducing the oxidizing gas of NO2. This study provides a promising prospect for the application of OFET in room temperature, low-cost and high sensitivity NO2 gas detectors, and describes the importance of active layer thickness to optimize the sensing properties of OFETs.

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

254th National Meeting (2017)

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