Metal Decoration Effects on the Gas-Sensing Properties of 2D Hybrid-Structures on Flexible Substrates

We have investigated the effects of metal decoration on the gas-sensing properties of a device with two-dimensional (2D) molybdenum disulfide (MoS(2)) flake channels and graphene electrodes. The 2D hybrid-structure device sensitively detected NO(2) gas molecules (>1.2 ppm) as well as NH(3) (>10 ppm). Metal nanoparticles (NPs) could tune the electronic properties of the 2D graphene/MoS(2) device, increasing sensitivity to a specific gas molecule. For instance, palladium NPs accumulate hole carriers of graphene/MoS(2), electronically sensitizing NH(3) gas molecules. Contrarily, aluminum NPs deplete hole carriers, enhancing NO(2) sensitivity. The synergistic combination of metal NPs and 2D hybrid layers could be also applied to a flexible gas sensor. There was no serious degradation in the sensing performance of metal-decorated MoS(2) flexible devices before/after 5000 bending cycles. Thus, highly sensitive and endurable gas sensor could be achieved through the metal-decorated 2D hybrid-structure, offering a useful route to wearable electronic sensing platforms.