Enhanced room-temperature NH3 gas sensing by 2D SnS2 with sulfur vacancies synthesized by chemical exfoliation

Recently, tin sulfide (SnS2) with different structures has been widely used for NH3 detection. However, the low sensitivity and high operating temperatures severely limit its potential application. Here, we demonstrate enhanced room temperature NH3 sensing using scalable SnS2 nanosheets, which are facily synthesized by chemical exfoliation. Structural and morphological characterization revealed that the as-prepared two-dimensional (2D) SnS2 is composed of 1-3 layers (0.6 nm-1.8 nm). Compared with the bulk SnS2 that shows none response to NH3, the gas sensors based on the as-prepared 2D SnS2 exhibit excellent ammonia gas sensing performance at room temperature. When exposed to 500 ppm ammonia, the response time, i.e., 16 s, is the shortest among all the NH3 gas sensors based on transition metal dichalcogenides (TMDs). We attribute this enhanced sensitivity mainly to the effective NH3 gas adsorption is dominated by the high energy defect sulfur vacancies on the surface of 2D SnS2. The easily synthesized 2D SnS2 with sulfur vacancies are expected to find a vast application in gas sensing.