Graphene has grabbed appreciable attention due to its exceptional physical, chemical, and electronic properties. Electrochemical applications of graphene are of great interest to many researchers as they can potentially lead to crucial technological advancements in fabrication of electrochemical devices for energy production and storage, and highly sensitive sensors [1]. From the other side of view, ionic liquids (ILs) have a large variety of applications in all areas of the chemical industries such as electrolyte in batteries. In this study a two layer of graphene plate was chosen to study the adsorption phenomena of hydrophobic ILs on the surface and compare two liquids with each other. The interfacial structure between 1-butyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl) imide, [C4mim]Tf2N, 1-butyl-3-methyl-imidazolium hexafluorophosphates, [C4mim]PF6, ILs and graphene double layer surface and basic mechanisms of graphene/IL interactions are simulated, aiming to model a crucial constituent of the electrolyte/semiconductor interface. The simulation results show several enhanced layers forming in the interfacial region, especially for the anions. A well ordered double layering structure of the ions is also observed in the interfacial region. The cations are found to organize themselves in a parallel alignment with respect to the slab, with an obvious elongation of the side chains. We found that IL stands over the plate at a distance of 3-5 Å at pressure value of 1 bar and does show a strong hydrophobic behavior at variance temperatures. The analysis of the simulation data results in the following most important conclusions: • There is an enrichment of all molecular components of IL under study at the surface with formation of several distinct layers at the graphene surface. • The non-polar tail of cation tends to lay parallel to the surface. • The work suggests that adsorption is a possible route to manage heat dissipation in graphene based nanoelectronic devices.

Keywords