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

Journal article, 2025

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.