Initial growth at the F16CoPc/Ag(111) interface

An extended, combined (STM/STS)-(UPS/XPS) study was carried out towards a comprehensive understanding of the mechanism responsible for the F16CoPc/Ag(111) interface formation. The evolution of the morphology and the electronic properties at the organic/metal interface is investigated for the early-stage growth of the ultrathin molecular film. Template-guided molecular structures are formed via a strong molecule-substrate interaction which leads to the formation of a new adsorption-induced interface state close to the Fermi energy (E-F). With increasing the thickness the molecular coupling to the metal surface states becomes less important while the more dominant molecule-molecule interaction governs the second layer formation. The quenching of the interface state upon increasing the molecular thickness, together with the changes observed in the Co 2p and F Is core levels, is explained based on a charge transfer at the interface and a corresponding charge redistribution within the molecular ligand. A detailed picture of the energy level alignment close to E-F is achieved by correlating the high resolution UPS and highly localized STS data. (C) 2011 Elsevier B.V. All rights reserved.