Phthalocyanine and Metal Phthalocyanines Adsorbed on Graphene: A Density Functional Study

Geometries of phthalocyanine (Pc) and metal (M = Cu, Fe, Zn, and Sn) Pc (MPc) adsorption on graphene have been studied using van der Waals density functional theory, which takes into account nonlocal correlation effects. The electronic properties were studied by the density functional theory. SnPc molecules energetically prefer to be adsorbed on the graphene surface with Sn-up conformation, which is different from the case of SnPc on the Ag(111) surface. For other MPcs, the centered metal atom remains within the plane of molecular backbone upon adsorbing on graphene surface. The adsorption of Pc and MPcs (M = Cu, Fe, Zn, and Sn) does not open the gap of graphene. Charges transfer slightly between the studied Pcs and graphene. The amount of charge transfer is the biggest, and the pattern of charge transfer is different for graphene-FePc.