High Sensitive Gas Sensor Based On Two-dimensional Selenide

Much attention have been focused on continuous on-site monitoring of air pollutant because of growing concern on environmental issues.Atmospheric pollutants cause many health problems including respiratory illnesses,changes in the lung’s defences and exacerbation cardiovascular disease.In the processes of monitoring,sensing pollutants gas molecules is crucial step.Therefore,there has been an increasing demand for sensing devices to monitor atmospheric pollutants.Most of the commercially available sensors based on solid electrolytes or metal oxides show either low sensing response or high operating temperature.So we need to find other materials with better sensing performance to optimize the gas sensor device.Two-dimensional（2D）nanomaterials（e.g.graphene,black phosphorus,etc.）are rapidly rising stars on the horizon of materials science,owing to its fascinating mechanical and electronic properties.Both graphene and black phosphorus have been found to perform well in gas sensors.However,the gapless nature of graphene impedes the way of its practical applications.Although black phosphorus has a large band gap and has better photoelectric properties than graphene,it is not stable in air.Hence,it is also not suitable for commercial promotion.Recently,the application of phosphorene structure analogues in gas sensors has been a hot research topic.Both SnSe and GeSe monolayer have similar structures to black phosphorus but have higher stability.Motivated by two-dimensional nanomaterials usage as sensors,we take great interest in developing two-dimensional selenide as gas sensors.The adsorption behaviors of gas molecules over SnSe and GeSe monolayer are theoretically investigated using first-principles calculations based on the density functional theory to explore the potential high-performance gas sensors.In this article,we calculate the electrical properties and adsorption capacity of SnSe monolayer adsorbed gas.For the GeSe monolayer,we calculate the electrical and optical properties after adsorbing gas molecules.The results show that the SnSe monolayer can be a potential alternate as the SO₂ sensors with high selectivity,sensitivity and considerable adsorption capacity.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.In addition,GeSe monolayer can adjust its optical properties by selectively adsorbing gas molecules.