Ultrasensitive gas sensor based on 3D assembled SnS2/SnO2 nanoflowers for NO2 detection at room temperature.

Nanostructures of SnO2 and SnS2 have been extensively studied for gas sensor application, but individual material faces some limitations such as low detection limits, poor selectivity, and high-power consumption. Nanohybrids of SnO2 and SnS2 are expected to achieve high sensing response at low temperatures, but their synthesis is challenging due to the complex processes. Herein, we synthesized SnS2 flower-like nanostructures decorated with SnO2 nanoparticles for enhanced gas-sensing performance via one-pot hydrothermal method using tin (IV) chloride pentahydrate and thiourea as precursors. By controlling the ratio of precursors, two phases of SnO2 and SnS2 were simultaneously obtained. The functionalizing effect of SnO2 nanoparticles on the morphology, structure and gas-sensing properties of SnS2 was systematically studied. Additionally, the impact of moisture on the sensing behaviors is investigated meticulously. On top of that, the synergetic effect of n-n SnS2/SnO2 junction is explicated in gas-sensing mechanism. These findings offer a feasible way to construct scalable and effective NO2 gas sensors for real-world applications.