Thin and transparent films of graphene/silver nanoparticles obtained at liquid–liquid interfaces: Preparation, characterization and application as SERS substrates

AbstractWe report here the synthesis and characterization of transparent and homogeneous thin films of reduced graphene oxide/silver nanoparticles (rGO/AgNPs) nanocomposites, starting from graphene oxide (GO) or reduced graphene oxide (rGO), directly obtained at a water/toluene liquid–liquid interface. Different films (obtained by varying the Ag/rGO or Ag/GO ratio) were prepared, deposited over glass or plastic substrates, and characterized by X-ray diffraction, UV–Vis and Raman spectroscopy, thermal analysis, transmission and scanning electron microscopy. Samples were evaluated as substrates for surface-enhanced Raman spectroscopy (SERS), using dilute solutions (1×10−7molL−1) of a common probe molecule, 4-aminothiophenol (4-ATP). These materials exhibit significant high-quality SERS activity, and enhanced modes could be observed for 4-ATP, which suggested that charge transfer occurred between the Ag nanoparticles and 4-ATP molecules