Rubidium Doped Metal-Free Phthalocyanine Monolayer Structures on Au(111)

Abstract

Scanning tunneling microscopy (STM) studies of monolayer of metal-free phthalocyanine (H 2 Pc) adsorbed on Au(111) have shown ordered arrangement of the molecules on the surface. Evaporation of H 2 Pc onto the Au(111) surface and post annealing of the sample to 670 K results in a densely packed structure of the molecules. The monolayer is characterized by molecules adsorbed with the molecular plane parallel to the substrate surface in a square adsorption unit cell. Furthermore, the high resolution images revealed the orientation of individual molecules. The H 2 Pc/Au(111) system has also been doped by rubidum and compared to the undoped layers. The Rb affects the molecular adsorption geometry, and a hexagonal unit cell is found for the coadsorption of H 2 Pc and Rb. Upon doping, highly ordered Rb-induced protrusions are observed at the benzene site of adsorbed molecules.