Suppression of plasmonic heating effect in SERS measurement by coating graphene on the Ag@AAO substrate surface

The plasmonic heating effect on the substrate surface prompted by laser radiation used in surface-enhanced Raman spectroscopy (SERS) measurement can inhibit the practical application of the SERS technique. Graphene, due to its high photothermal conversion and thermal conductivity, could provide a rapid path for dissipating the heat generated from hot electrons. In this work, the diluted graphene was spin-coated onto the anodized aluminum oxide (AAO) template modified with Ag films (G@Ag@AAO) to suppress the plasmonic heating effect. Theoretical simulations demonstrated that the ultrathin graphene coating can promote the plasmonic coupling between adjacent Ag nanoislands. The in-situ SERS monitoring revealed that the G@Ag@AAO substrate exhibits better signal stability than the pristine Ag@AAO substrate. Besides, ultraviolet (UV) radiation caused cross-linking of PVA (polyvinyl alcohol)/G (graphene) nanocomposites on the Ag@AAO substrate surface, which made the PVA/G@Ag@AAO substrate exhibit more excellent long-term detection stability in solution due to the increases of PVA/G interfacial adhesion toughness. In addition, the excellent λ-DNA (dsDNA) identification ability of PVA/G@Ag@AAO substrate suggests its broad prospect in biomolecular sensing and genetic engineering applications.