Long ‐Range Surface‐Assisted Molecule‐Molecule Hybridization

On a silver surface, magnesium phthalocyanine molecules undergo a perturbation of their electronic structure as a result of an attractive interaction with their nearest ‐neighbors. Quantitative agreement with supporting theoretical modelling indicates that this interaction consists of multiple‐nanometer‐range intermolecular hybridization enabled by the underlying substrate. These observations offer new possibilities to control electronic properties for engin eered nanomaterials. AbstractMetalated phthalocyanines (Pc's) are robust and versatile molecular complexes, whose properties can be tuned by changing their functional groups and central metal atom. The electronic structure of magnesium Pc (MgPc) —structurally and electronically similar to chlorophyll—adsorbed on the Ag(100) surface is investigated by low‐temperature scanning tunneling microscopy and spectroscopy, non‐contact atomic force microscopy, and density functional theory. Single, isolated MgPc's exhibit a flat, fourfold rota tionally symmetric morphology, with doubly degenerate, partially populated (due to surface‐to‐molecule electron transfer) lowest unoccupied molecular orbitals (LUMOs). In contrast, MgPc's with neighbouring molecules in proximity undergo a lift of LUMOs degeneracy, with a near‐Fermi local densi ty of states with reduced twofold rotational symmetry, indicative of a long‐range attractive intermolecular interaction. The latter is assigned to a surface‐mediated two‐step e...
Source: Small - Category: Nanotechnology Authors: Tags: Full Paper Source Type: research