Raman spectroscopy as a probe for the electronic structure of graphene at electrified interfaces

Abstract

As all the atoms in monolayer graphene are on its surface, it is strongly influenced by its environment. Surface-charge transfer of graphene changes its properties including the electrical conductivity, carrier mobility, capacitance, and reactivity. The charge transfer occurs between the graphene and its substrate, and can be controlled by the electrode potential in electrochemical cells. The charge of graphene is related to its Fermi level and Fermi energy, which determines the rates of the electrochemical and photoelectrochemical reactions occurring. The simplest method to measure the charge density of graphene is Raman spectroscopy. Here, we review Raman spectroscopy measurement of graphene charge, especially that in electrochemical environments, with emphasis on its potential application in electrochemical and photoelectrochemical reactions for energy conversion.