A First-principles Study on Strain-induced Change of Adsorption Behaviour of Gas Molecules on Graphene for Multi-gas Detecting Sensor

Abstract

In order to improve the selectivity, the interaction between graphene and various gas molecules (CO, H2O, and NH3) with and without applied tensile strain were calculated by using first-principles calculation. The changes in adsorption energy and charge transfer (including Bader charge analysis and charge density difference) were further investigated by applying 0%-10% uniaxial tensile strain on the graphene surface. It was found that the adsorption behavior of distinct gas molecules on the graphene surface varied linearly and has different trends under the application of tensile strain. Some gas molecules such as CO and NH3 gradually desorbed, while other gas molecule such as H2O, on the contrary, adsorb more stably with increasing tensile strain. These findings provide feasibility and guidance for further experiments that strain engineering can be used to improve the selectivity of graphene-based gas sensors for further applications in health monitoring.