Co-localized scanning probe microscopy-Raman scattering studies of hybrid plasmonic substrates for SERS

• Plasmonic substrates based on graphene oxide and pulsed laser synthsized gold nanoparticles offer improved SERS performance. • Co-localized Kelvin probe force microscopy and Raman maps correlate topography, surface potential, and SERS at the nanoscale. • GO serves as NP support, improving dispersion and reproducibility, and facilitates adsorption of organic polar molecules. Hybrid plasmonic substrates based on graphene oxide (GO) sheets decorated with colloidal gold nanoparticles (NPs) have been tested for surface-enhanced Raman scattering (SERS). By leveraging the high chemical reactivity of GO and the plasmonic characteristics of gold NPs, these hybrid substrates exhibit improved SERS performance. The morphology and electro-optical properties of the GO-Au NP nanohybrids are thoroughly characterized using scanning probe microscopies, including Kelvin probe force microscopy. Maps of the substrates topography and surface potential are then correlated with the local SERS enhancement factors through co-localized confocal Raman spectroscopy, providing valuable insights into the structure–function relationships of the hybrid plasmonic substrates and contributing to the understanding of SERS mechanisms. The inexpensive and straightforward fabrication process offers a cost-effective and user-friendly approach, while the incorporation of GO sheets provides a scalable and versatile platform, further enhancing the applicability and utility of these substrates.