Silver nanoparticles protected by monolayer graphene as a stabilized substrate for surface enhanced Raman spectroscopy

Silver nanostructures have been extensively studied as the substrates for surface-enhanced Raman spectroscopy (SERS) due to their strong plasmonic enhancement effect and low loss at optical frequencies. However, unprotected silver nanostructures are chemically unstable under practical conditions, leading frequently to erratic SERS signals and possibly unreliable interpretation of experimental results. Herein, we show that a single layer of graphene grown by chemical vapor deposition can effectively stabilize silver nanoparticles against aerobic oxidation and that the protected nanoparticles can be used as a stable substrate for the production of enhanced SERS signals for up to 28 days under ambient conditions.