Two-dimensional SnS2 materials as high-performance NO2 sensors with fast response and high sensitivity

The rapid development of modern industry has resulted in increased emissions of nitrogen dioxide gas in recent decades. In order to develop ubiquitous environmental monitoring system suitable for the Internet of Things (IoT) paradigm, the high-sensitivity and fast-response detection of NO2 gas at low concentrations is of particular importance. Recently, two-dimensional (2D) materials have shown fast response/recovery characteristics in the detection of NO2, due to their planar crystal structures, large surface-to-volume ratios, and low electronic noise. Among these materials, tin disulfide has shown superior sensing performances, at the parts-per-million (ppm) level, in addition to fast response and good stability. Therefore, here we report the synthesis of 2D SnS2 materials via high-energy ball milling (HEBM), followed by characterization of the crystal structures and morphologies of the products by X-ray diffraction and transmission electron microscopy. The use of the present SnS2 nanomaterial as a NO2 sensor enables the detection of a wide range of gas concentrations (from parts-per-billion (ppb) to ppm levels) with fast response and high sensitivity, at an optimal operating temperature of 250 °C. Under these conditions, the sensor exhibited a response >2000% and response/recovery times of 6/40 s at an NO2 concentration of 10 ppm. Finally, the sensor developed in this work also produced highly repeatable and linear responses.