Blue phosphorus phase GeSe monolayer for nitrogenous toxic gas sensing: A DFT study

Abstract

Continuing industrialization, a variety of toxic gases are emitted into the air, yet gas concentrations at low levels are extremely hard to detect. So the development of high-performance toxic gas sensors is imminent. Two-dimensional materials with advantages such as large specific surface area and unique electronic properties open new paths for gas sensors. In this study, a monolayer of blue phosphorus phase germanium selenide (GeSe) was used as the substrate material. The absorption performance of ambient nitrogenous toxic gases (NO, NO2, NH3, N2O) on the surface of GeSe monolayers was explored by the density-functional theory (DFT) calculations. The results show that the interaction between GeSe and the four gases exhibits physisorption. Based on four optimal adsorption structures, Bader charge, work function, band structure, density of states, and recovery time were calculated. Charge transfer is promoted due to the presence of GeSe intrinsic dipoles and only NH3 was found to be the charge donor. The significant changes in work function and electronic properties of GeSe monolayer adsorption of NO indicate significant changes in electrical signals during gas detection. This work reveals that GeSe monolayer has higher sensitivity and selectivity for NO hazardous gas.