Toxic gases molecules (NH3, SO2 and NO2) adsorption on GeSe monolayer with point defects engineering

Highlights: • The adsorption of the gas molecules on point defects in GeSe monolayer introduces new state around the Fermi level. • The GeSe monolayer with point defects engineering has potential application in gas sensing. • The work function of GeSe monolayer with defect engineering is highly sensitive to gas molecules. First-principles calculations are performed to study the structure, stability, density of states and work function of toxic gases (NH₃, SO₂ and NO₂) molecules adsorption on GeSe monolayer with point defect engineering, including Ge/Se mono-vacancy, anti-site defect, and P atom substituted defect. Our results on the adsorption energy, charge transfer and electron localization function show that the interaction between gas molecules and point defects in GeSe monolayer is sensitive, which causes significant modification to the electronic structure and work functions of GeSe monolayer.