Graphene-based gas sensor: metal decoration effect and application to a flexible device

Abstract

Roles of metal nanoparticles (NPs) on graphene-based devices were investigated in terms of gas-sensing characteristics of NO₂ and NH₃, and flexible gas sensing was also realized for future applications. The synergistic combination of metal NPs and graphene modulates the electronic properties of graphene, leading to enhancement of selectivity and sensitivity in gas-sensing characteristics. Introduction of palladium (Pd) NPs on the graphene accumulates hole carriers of graphene, resulting in the gas sensor being sensitized by NH₃ gas molecular adsorption. In contrast, aluminum (Al) NPs deplete hole carriers, which dramatically improves NO₂ sensitivity. Furthermore, the sensitivity of flexible graphene-based gas sensors was also enhanced via the same approach, even after 10⁴ bending cycles and was maintained after 3 months.