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O: Fachverband Oberflächenphysik

O 47: Metal substrates: Adsorption of organic / bio molecules V

O 47.9: Vortrag

Mittwoch, 24. März 2010, 12:30–12:45, H36

STM and STS study at the organic-metal interface: Adsorption of CoPc on Ag(111) surface — •Marius Toader, Pavel Shukrynau, and Michael Hietschold — Chemnitz University of Technology, Institute of Physics, Solid Surfaces Analysis Group, D-09107 Chemnitz, Germany

In this work, we have studied the interface effects which arise upon adsorption of cobalt(II)-phthalocyanine (CoPc) on a silver (111) surface, in terms of morphology and electronic properties. The organic ultra-thin film corresponding to a slightly sub-monolayer coverage has been prepared using OMBD and investigated with an UHV VT-STM from Omicron. A strong molecule-substrate coupling is emphasized by template-guided molecular arrangements of single molecules, molecular nanochains and extended molecular domains. Therefore, the reported highly-oriented adlayer structures, like pseudo-square and superstructures with different molecular appearance, have to be discussed. The electronic properties at the organic-metal interface, are discussed based on voltage polarity-dependent STM imaging and tip-sample distance-dependent scanning tunneling spectroscopy. A molecular HOMO-LUMO gap narrowing has been reported with decreasing tip-sample distance. Moreover, the features in the superstructure exhibit slightly different electronic properties. For a better understanding of the interface effects, single molecule DFT calculations were also employed and compared with STS data.