Low-operating temperature NO2 gas sensors based on hybrid two-dimensional SnS2-reduced graphene oxide

The excellent sensing capabilities of SnS2 and the electrical properties of reduced graphene oxide (rGO) are combined to achieve a low-operating temperature NO2 gas sensor. Conductometric gas sensors based on hybrid films of 2D SnS2-rGO are fabricated and evaluated for humidity and different target gases including NO2, CH4, NH3, C2H5OH (ethanol), (CH3)2CO (acetone) at different operating temperatures ranging from 25 °C to 100 °C. The sensor shows exclusive selectivity and reversibility to NO2 as compared to the other analytes, with a low detection limit of 0.6 ppm and a response of 9.8% at 80 °C. The sensing mechanism of the hybrid SnS2-rGO system is described by analysing the effect of NO2 gas on the depletion region established at the interface between SnS2 and rGO layers.