Sensitive surface-enhanced Raman scattering activity of triple gold/silver/graphene oxide nanostructures decorated on gold nanowire arrays

Triple core-shell gold/silver/graphene oxide (Au/Ag/GO) nanoparticles (NPs) decorated on Au nanowire arrays as sensitive, reproducible, and low-cost platforms for surface-enhanced Raman spectroscopy (SERS) were introduced. An in situ reducing method was used to synthesize core-shell Au/Ag NPs with inbuilt 4-mercaptobenzoic acid, which gave prominent SERS signals. Subsequently, a second ultrathin shell of GO was constructed on the Ag shell to improve the SERS intensity and homogeneity. Details on stability of the Raman enhancement were discussed by mapping of SERS spectra. A composite structure was finally designed by decorating the triple core-shell Au/Ag/GO NPs onto a vertically aligned ultrathin Au nanowire forest to provide additional enhancement of the SERS signals. This hetero structure will provide an alternative choice for the effective SERS substrate.