Effect of structural defects in graphene on the geometry and electronic properties of adsorbed lanthanide bisphthalocyanines: A DFT analysis

Abstract

We studied by means of density functional theory (at the PBE-D2/DN level) the adsorption on pristine and defect-containing graphene models (GMs) of three lanthanide(III) bisphthalocyanines of general formula LnPc2, represented by LaPc2, GdPc2 and LuPc2, in which Ln atom has totally empty, half-filled and totally filled 4f orbitals, respectively. Our goals were to compare the strength of noncovalent interactions with different graphene models, as well as to estimate possible changes (compared to isolated molecules) in LnPc2 geometry, frontier orbital energies and their distribution, charge and spin characteristics of the central Ln atom. The most general effect is that bisphthalocyanines tend to increase the area of contact with graphene surface, which causes notable distortion of the Pc ligand contacting GM. The interactions are rather strong, whose strength depends on the GM topology. The pattern of frontier orbital and spin distribution is variable.