Control of the Adsorption Behavior of Gas Molecule on Graphene by Strain: First-Principles Calculations for Development of Multi-Gas Selective Sensors

Graphene is a promising material for gas sensing because of its unique electrochemical properties. Previous studies have revealed that the adsorption and desorption of gas molecules on graphene were controlled by mechanical strain. In this study, first-principles calculation was applied to the investigation of the effect of tensile and compressive strains on the gas adsorption properties of graphene. It was found that the adsorption energy varied almost linearly with the applied strain due to the change of its electronic band structure and, consequently, it caused the change of the magnitude of the charge transfer between them. Among them, NO2 exhibited greater strain sensitivity, specifically, its adsorption energy increased by about 70% under compressive strain of 10%. The non-equilibrium green function (NEGF) method was also performed to confirm that the I-V characteristic was changed by the adsorption of gas molecules and strain. Notably, it was found that the change of current was about 14 times larger than that observed in 10%-tensile-strained graphene adsorbed with H2O system when no strain was applied. Overall, our results validated that tuning the gas binding behavior of graphene by application of strain is a promising approach for developing multi-gas sensors with high selectivity.