Plasmon-activated NO2 sensor based on Au@MoS2 core-shell nanoparticles with heightened sensitivity and full recoverability

Abstract

Developing high-performance gas-sensing devices based on transition metal dichalcogenides (TMDs) has sparked significant research interest in efficient detection of hazardous gases at room temperature. Considering that the gas-sensing performances of TMDs-based sensors can be effectively improved by the localized surface plasmon resonance (LSPR) effect of decorated noble-metal nanoparticles, herein, we explored the LSPR effect on gas-sensitive features via the design of a visible-light-assisted gas sensor using Au@MoS2 core-shell heterostructures as sensitive materials. The internal connection between the optical absorption and the gas-sensing properties of Au@MoS2 heterostructures was investigated. Intriguingly, under the activation of indoor white-light, the optimized Au@MoS2 sensor displayed an enhanced response by more than 8 times and elevated recoverability from 60% to 98% almost without baseline shift as compared with the pure MoS2 gas sensor for the detection of NO2 (1 ppm). The combination of experimental and theoretical analysis indicates that the improved gas-sensing performances can be primarily attributed to the effective amplification of the light absorption efficiency of MoS2 induced by the LSPR effect from the Au nanoparticle cores. These results imply a potential application in monitoring NO2 gas at room temperature and open up an effective thoughtway for developing high-performance visible-light-modulated gas sensors.