Electrochemical Tuning of Graphene Enhanced Raman Spectroscopy*

In this talk I will review our recent progress in electrochemical tuning of graphene enhanced Raman spectroscopy (GERS). We developed a novel approach to probe the local ion concentration at graphene/water interfaces using in situ Raman spectroscopy. Monolayer graphene grown by chemical vapor deposition (CVD is used as the working electrode in a three-terminal potentiostat while Raman spectra are measured in situ under applied electrochemical potentials using a water immersion lens.The charge density in the graphene electrode is also measured independently using the capacitance-voltage characteristics and is found to be consistent with those measured by Raman spectroscopy. Then, CuPc molecules are deposited on the graphene. GERS spectra are then taken in an aqueous solution as a function of the applied electrochemical potential. A 50% modulation in the Raman intensity as a function of the applied potential.