Two-dimensional MoSe ₂ nanosheets via liquid-phase exfoliation for high-performance room temperature NO ₂ gas sensors

Abstract

Abstract Molybdenum selenide (MoSe 2 ) has drawn significant interest due to its typical semiconductor properties. MoSe 2 is a relatively novel material in the field of gas sensors especially at room temperature. Herein, we utilize a facile and efficient synthetic method of liquid-phase exfoliation to exfoliate bulk MoSe 2 into nanosheets. Anhydrous ethanol is used as dispersant, so the low boiling point makes it easy to be removed from MoSe 2 nanosheets, which does not affect the subsequent sensing performance. The exfoliated few-layered MoSe 2 nanosheets shows significantly enhanced NO 2 gas response (1500% to 10 ppm NO 2 which is 18 times greater than pristine bulk MoSe 2 ), a low detection concentration (50 ppb), an outstanding repeatability, a remarkable selectivity, and a reliable long-term device durability (more than 60 d) at room temperature (25 °C). The reason of the significant improvement in gas sensing performance can be attributed mainly to the higher surface-to-volume ratio of exfoliated MoSe 2 nanosheets. It promotes the adsorption of gas molecules on the surface of the material, thereby facilitating the charge transfer process. The superior performance of this gas sensor makes MoSe 2 nanosheets a potential candidate for room temperature NO 2 detection.