A Novel Ultra-Sensitive Nitrogen Dioxide Sensor Based on Germanium Monosulfide Monolayer

Nitrogen dioxide (NO
₂
) is a representative toxic gas that plays a key role in variety of fields. Due to its extensive application, the demands for reliable sensors to detect NO
₂
are extremely urgent. Here, we report the adsorption of N
₂
, CO
₂
, O
₂
, and NO
₂
molecules on the GeS monolayer from atomic scale to device scale by first principles and molecular dynamics method. The results indicate that the GeS monolayer is sensitive to NO
₂
molecules with moderate adsorption energy and pronounced charge transfer. Remarkably, the sorption quantity of the GeS monolayer for NO
₂
is 708.707 mg/g under the 101.33 kPa, which is much higher than other molecules. Additionally, the I-V characteristic reveals that when the NO
₂
molecule is adsorbed, the resistance of the GeS monolayer is nontrivially and distinctly changed. The extraordinary sensitivity and selectivity of the GeS monolayer for NO
₂
molecules suggests the GeS monolayer is a potential sensing material for NO
₂
gas.