Chemical reaction of polar phthalocyanines on silver: Chloroaluminum phthalocyanine and fluoroaluminum phthalocyanine

Interface properties of chloroaluminum(III) phthalocyanine (AlClPc) and fluoroaluminum(III) phthalocyanine (AlFPc) on different silver surfaces have been studied using X-ray and ultraviolet photoemission spectroscopy (XPS and UPS) and X-ray absorption spectroscopy (XAS). Both polycrystalline silver foil and silver single crystals were used as a substrate. In all cases a chemical reaction was detected by XPS, visible as additional species in chlorine or fluorine core level spectra. However, UPS spectra show additional intensity in vicinity of the Fermi edge only for monolayer coverages of AlClPc and AlFPc on silver foil. Possible scenarios for the different interaction on polycrystalline and single-crystalline silver surfaces are discussed. The roughness of the substrate may influence the strength of the interaction significantly.