Ni and Cu octaethyl porphyrins ordered monolayer on Au(111) surfaces

Structural profiles and electronic properties of a CuOEP and NiOEP ordered monolayer on an Au(111) substrate were studied by photoemission and Low Energy Electron Diffraction (LEED). The porphyrin molecules were deposited on Au(111) under Ultra High Vacuum (UHV) conditions. In this study, we focused on the central atom's effect on the molecule-substrate interaction. In the photoemission valence band measurements, the energy separation among different molecular states was measured and was found smaller than in free molecules. The smaller energy separation value suggested a charge transfer mechanism in the interface bond formation. The LEED showed that the monolayer depositions exhibited well ordered patterns and that the structures depended on the central atoms.