Visible light assisted trace gaseous NO2 sensor with anti-humidity ability via LSPR enhancement effect

Abstract

Transition metal dichalcogenides (TMDs) have been received widespread attention for NO2 detection at room temperature. However, the TMDs-based gas sensors usually possess inferior response capability and suffer from humidity interference due to lack of sufficient reaction activation energy, which seems tough to achieve the detection of ppb-level gases and hinder the practical applications. Herein, we propose a visible light-assisted-type gas sensor based on Au-decorated WS2, endowing high-performance detection of NO2 at room temperature. Benefited from the localized surface plasmon resonance (LSPR) enhancement effect induced by the modified Au nanoparticles (NPs), the visible light-assisted Au/WS2 gas sensor can implement the detection of NO2 gas as low as 20 ppb. Moreover, the maximum drift of the sensor response value is only 3% in the range of 10%−90% RH, indicating the stabilized anti-humidity ability. The effective regulation of transmission channel by the modified noble metal and the enhancement of visible light absorption of WS2 through taking full advantage of the LSPR effect are the main reasons for realizing low concentration detection and improving the anti-humidity ability. Therefore, the visible light-assisted gas detection mode can serve as a proof-of-concept to provide an effective approach for the detection of trace gases at room temperature.