Humidity‐Enhanced NO2 Gas Sensing Using Atomically Sharp Edges in Multilayer MoS2

Abstract

Ambient humidity poses a significant challenge in the development of practical room‐temperature NO2 gas sensors. Herein, atomically precise zigzag edges are employed in multilayer MoS2, fabricated using electron beam lithography and anisotropic wet etching, to achieve highly sensitive and selective gas‐sensing performance, that is, humidity‐tolerant at elevated temperatures and humidity‐enhanced at room temperature under ultraviolet illumination. Notably, exposure to 2.5 parts per billion (ppb) NO2 at 70% relative humidity under ultraviolet illumination and at room temperature resulted in a 33‐fold increase in response and a 6‐fold faster recovery compared to 0% relative humidity, leading to response values exceeding 1100%. The optimized samples demonstrate a theoretical detection limit ranging from 4 to 400 parts per trillion (ppt) NO2. The enhanced NO2 sensing capabilities of MoS2 edges have been further confirmed through first‐principles calculations. This study expands the applications of nanostructured MoS2 and highlights its potential for detecting NO2 at sub‐ppb levels in complex scenarios, such as high‐humidity conditions.

Keywords

• chemiresistive gas sensing
• nanostructured molybdenum disulfide (MoS2)
• nitrogen dioxide (NO2) gas sensing
• relative humidity
• transition metal dichalcogenides