High Selective Gas Detection for small molecules based on Germanium selenide monolayer

Predictive calculations based on density functional theory (DFT) are used here to study the electronic and optical properties of GeSe monolayer after adsorbing gas molecules (O₂, NH₃, SO₂, H₂, CO₂, H₂S, NO₂, CH₄, H₂O, NO, CO). Our results reveal that for all the gas molecules considered, only NH₃ is adsorbed on GeSe monolayer by physisorption. Whereas SO₂ and NO₂ are chemisorbed on GeSe monolayer with strong adsorption energies. In addition, the adsorption of O₂, NO and NO₂ distinctly enhances the optical absorbance and broaden the absorbance range of GeSe monolayer in visible light region. Also, it is found that the adsorption of H₂S, NO and NH₃ can reduce the work function of the GeSe monolayer. The results indicate that GeSe monolayer is not only a promising candidate for the sensing, capture, and storage of NH₃, but also an anticipated disposable gas sensor or metal-free catalyst for detecting and catalyzing SO₂ and NO₂. Furthermore, it has excellent potential to be applied to optical sensors, solar cells, nanoelectronics or optoelectronics devices.