An ultra-sensitive and selective nitrogen dioxide sensor based on a novel P2C2 monolayer from a theoretical perspective

Abstract

The sensing properties of an α phase black phosphorus carbide (P₂C₂) monolayer for the adsorption of CO₂, H₂, H₂O, N₂, H₂S, NH₃, O₂ and NO₂ gases are theoretically investigated using first-principles calculations. We calculate the adsorption energy, equilibrium distance, Mulliken charge transfer, electron localization function, and work function to explore whether P₂C₂ is suitable for detecting NO₂ gas. The results demonstrate that the P₂C₂ monolayer is highly sensitive and selective to NO₂ gas molecules with robust adsorption energy and superior charge transfer due to the existence of strong orbital hybridization between the NO₂ molecule and monolayer P₂C₂. In addition, the results of the work function calculations indicate that field effect transistor type NO₂ gas sensors based on P₂C₂ monolayers are also feasible. Furthermore, the current–voltage curves reveal that the adsorption of NO₂ can greatly modify the resistance of the P₂C₂ monolayer. Our results show that gas sensors based on P₂C₂ monolayers could be better than those based on black phosphorene (BP) for detecting NO₂ molecules in an air mixture. In addition, the recovery time of the P₂C₂ sensor at T = 300 K was estimated to be short (and even shorter at higher temperatures) for NO₂ which satisfies the demands for sustainable use.