Inorganic gas sensing of green phosphorene nanosheet: insights from density functional theory

Our work highlights the functionality of a novel two-dimensional phosphorene allotrope entitled green phosphorene for inorganic gas detection for the first time. Four inorganic molecules, NH₃, SO₂, HCN and O₃, are considered as adsorbates and the adsorption conformation, adsorption energy, charge transfer, density of states, and electronic band structure are systematically scrutinized based on density functional theory. Our calculations show that the adsorption energy of O₃on pristine green phosphorene is the lowest among the four considered gas molecules, suggesting that the substrate is more sensitive to O₃. Significant changes in electronic structures confirm the possibility of green phosphorene for O₃detection. Biaxial strains and electric fields were applied to investigate the changes in adsorption behavior. The presence of compressive strain could enhance adsorption sensitivity between O₃and green phosphorene, while the tensile strain induces the dissociative adsorption that not suitable for reversible sensor. Furthermore, by controlling the orientation of external electric field, it is possible to achieve O₃adsorption-desorption cycle, which is of great significance for green phosphorene in the application of reversible gas sensor.