Stabilizing MoS2 Nanosheets through SnO2 Nanocrystal Decoration for High-Performance Gas Sensing in Air

The unique properties of MoS2 nanosheets make them a promising candidate for high-performance room temperature sensing. However, the properties of pristine MoS2 nanosheets are strongly influenced by the significant adsorption of oxygen in an air environment, which leads to instability of the MoS2 sensing device, and all sensing results on MoS2 reported to date were exclusively obtained in an inert atmosphere. This significantly limits the practical sensor application of MoS2 in an air environment. Herein, a novel nanohybrid of SnO2 nanocrystal (NC)-decorated crumpled MoS2 nanosheet (MoS2/SnO2) and its exciting air-stable property for room temperature sensing of NO2 are reported. Interestingly, the SnO2 NCs serve as strong p-type dopants for MoS2, leading to p-type channels in the MoS2 nanosheets. The SnO2 NCs also significantly enhance the stability of MoS2 nanosheets in dry air. As a result, unlike other MoS2 sensors operated in an inert gas (e.g. N-2), the nanohybrids exhibit high sensitivity, excellent selectivity, and repeatability to NO2 under a practical dry air environment. This work suggests that NC decoration significantly tunes the properties of MoS2 nanosheets for various applications.