Electroinduced Intercalation of Tetraalkylammonium Ions at the Interface of Graphene Grown on Copper, Platinum, and Iridium

Electrochemically driven intercalation of tetraalkylammonium ions can facilitate the delamination of graphene films fabricated by chemical vapour deposition (CVD) from their supporting metal catalyst and, hereby, ease the transfer of the graphene to other substrates. The electroinduced intercalation is performed by applying a negative potential to the metal/graphene cathode, while immersed into an electrolyte solution of the tetraalkylammonium ions in acetonitrile. As part of the double layer the cations intercalate the interface between the metal and the graphene, which increases the interfacial distance as well as weakens the interaction with and the screening effect of the metal. The individual stages of the intercalation and delamination were studied for CVD grown graphene on Cu, Pt, and Ir. Experimentally, the intercalation is seen to give a significant increase in the intensity of the recorded Raman spectra and most of the compressive strain in graphene is released. The electroinduced intercalation does not increase the defect or doping levels of graphene. Also, it is shown that easy transfer of the intercalated graphene to Si/SiO2 can be accomplished. Under the graphene sea: Electrochemical charging of graphene allows the intercalation of tetraalkylammonium ions at the metal/graphene interface. This simple procedure decouples the graphene and relieves strain. The electroinduced intercalation does not damage the graphene, and it facilitates transfer of graphene from various metals such as Cu, Pt, and Ir.