Surface enhanced Raman spectroscopy platform based on graphene with one-year stability

• Synthesis of graphene film from amorphous carbon by pulsed laser deposition with nickel catalyst
• Large scale textured graphene with nanoscale roughness obtained through nickel silicide formation
• Films used for surface enhanced Raman spectroscopy detection of organophosphate compounds
• Stability of the SERS platforms over up to one year

We report the synthesis, characterization and use of a robust surface enhanced Raman spectroscopy platform with a stable detection for up to one year of Rhodamine R6G at a concentration of 10− 6 M. The detection of aminothiophenol and methyl parathion, as active molecules of commercial insecticides, is further demonstrated at concentrations down to 10− 5–10− 6 M. This platform is based on large scale textured few-layer (fl) graphene obtained without any need of graphene transfer. The synthesis route is based on diamond-like carbon films grown by pulsed laser deposition, deposited onto silicon substrates covered by a Ni layer prior to diamond-like carbon deposition. The formation of fl-graphene film, confirmed by Raman spectroscopy and mapping, is obtained by thermal annealing inducing the diffusion of Ni atoms and the concomitant formation of nickel silicide compounds, as identified by Raman and Auger electron spectroscopies. The textured fl-graphene films were decorated with gold nanoparticles to optimize the efficiency of the SERS device to detect organic molecules at low concentrations.