Can Inorganic Salts Tune Electronic Properties of Graphene?

Electronic properties of graphene quantum dots (GQDs) constitute a subject of intense scientific interest. Being smaller than 20 nm, GQDs contain confined excitons in all dimensions simultaneously. GQDs feature a non-zero band gap and luminesce on excitation. Tuning their electronic structure is an attractive goal with a technological promise. In this work, we apply density functional theory to study an effect of neutral ionic clusters adsorbed on GQD surface. We conclude that both HOMO and LUMO of GQD are very sensitive to the presence of ions and to their distance from the GQD surface. However, the alteration of the band gap itself is modest, as opposed to the case of free ions (recent reports). Our work fosters progress in modulating electronic properties of nanoscale carbonaceous materials.