MoS₂ Nanoflowers Decorated with Au Nanoparticles\nfor Visible-Light-Enhanced Gas Sensing

Abstract

Highly sensitive and selective detection\nof trace nitrogen dioxide\n(NO₂) in a complex outdoor air environment is an urgent\nneed to guarantee human health and a beautiful environment. The effective\ncombination of heterostructure and light irradiation is an important\nstrategy to achieve high-performances gas sensors. However, the effect\nof light irradiation on gas-sensitive properties of heterostructure\nmaterials is not yet clear, and it is urgent to clarify the relationship\nbetween light irradiation and heterostructure for gas-sensing materials.\nHerein, a 530 nm-light-assisted Au–MoS₂ gas sensor\nwith a low detection limit as well as robust antihumidity interference\nability is developed through introducing the localized surface plasmon\nresonance (LSPR) effect of Au nanoparticles (NPs). Under 530 nm light\nillumination, a Au–MoS₂ gas sensor can achieve limit\ndetection of NO₂ as low as 10 ppb without operating temperature\nalong with robust antihumidity ability. The optical simulation and\nexperimental results show that the modification of MoS₂ by Au NPs (diameter: 30 nm) combined with the matching light-assisted\n(530 nm) gas detection mode can make MoS₂ fully absorb\nvisible light and effectively improve the extinction cross section\nby taking full advantage of the LSPR effect, which is the primary\nreason for the enhanced performances of a MoS₂-based gas\nsensor. This work provides theoretical and experimental guidance for\ngas sensors to effectively enhance the ability of gas detection by\nmeans of the light-assisted mode at room temperature, which opens\nup a unique approach to design high-performance gas sensors for trace-level\ngas detection.