Gas Sensors Based on Mechanically Exfoliated MoS₂ Nanosheets for Room-Temperature NO₂ Detection

The unique properties of MoS₂ nanosheets make them a promising candidate for high-performance room temperature gas detection. Herein, few-layer MoS₂ nanosheets (FLMN) prepared via mechanical exfoliation are coated on a substrate with interdigital electrodes for room-temperature NO₂ detection. Interestingly, compared with other NO₂ gas sensors based on MoS₂, FLMN gas sensors exhibit high responsivity for room-temperature NO₂ detection, and NO₂ is easily desorbed from the sensor surface with an ultrafast recovery behavior, with recovery times around 2 s. The high responsivity is related to the fact that the adsorbed NO₂ can affect the electron states within the entire material, which is attributed to the very small thickness of the MoS₂ nanosheets. First-principles calculations were carried out based on the density functional theory (DFT) to verify that the ultrafast recovery behavior arises from the weak van der Waals binding between NO₂ and the MoS₂ surface. Our work suggests that FLMN prepared via mechanical exfoliation have a great potential for fabricating high-performance NO₂ gas sensors.