Hole-transporting polymer dilution driven high performance organic transistor-based NO2 gas sensor

Solution-processed organic field-effect transistor (OFET) has great potential in detecting various hazardous gases including nitrogen dioxide (NO2). To overcome the bottleneck of weak gas adsorption/interaction capability in single-semiconductor sensing layer, semiconductor composites are used to enhance the sensing response. Here, we report an OFET-based NO2 sensor whose active layer consists of diluted poly(3-hexylthiophene-2,5-diyl) (P3HT) with poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (poly-TPD). Due to the site-increase effect induced by phase segregation, the 90% diluted device possesses a more than 3-fold enhancement of current responsivity. Furthermore, when the gate voltage is switched from -40 V to 0 V, this device embodies 4.6-fold and 43.6-fold improvements at 0.3 ppm and 30 ppm, respectively. Meanwhile, decent selectivity, environmental stability and an excellent limit of detection of 242.6 ppb are realized. (C) 2018 Elsevier B.V. All rights reserved.