Regensburg 2007 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 16: Organic, Polymeric, and Biomolecular Films I
O 16.3: Vortrag
Montag, 26. März 2007, 14:45–15:00, H42
Electronic and geometric structure of F4TCNQ on Cu(111): A joint experimental and theoretical study — Lorenz Romaner1, Alexander Gerlach2, Frank Schreiber2, Steffen Duhm3, Norbert Koch3, Gerold Rangger4, Georg Heimel4, Jean-Luc Brédas1, and •Egbert Zojer1 — 1Institut für Festkörperphysik, Technische Universität Graz, A-8010 Graz, Austria — 2Institut für Angewandte Physik, Universität Tübingen, 72076 Tübingen, Germany — 3Institut für Physik, Humboldt-Universität zu Berlin, D-12389 Berlin, Germany — 4School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, USA
The physical and chemical properties of organic/metal interfaces are of high interest for organic and molecular electronics. We present results of ultraviolet photoelectron spectroscopy (UPS) and X-ray standing wave (XSW) measurements for F4TCNQ adsorbed onto the copper (111) surface.
To gain insight into the nature of the interaction between the metal and the molecules, the interface was modeled by means of density functional theory band-structure calculations using the VASP code. The results provide an accurate description of charge donation from the -CN lone pairs to the metal and the back donation from the metal into the molecular LUMO. The molecules are strongly bent and display a transition from a quinoidal to a benzoidic structure. From a real space analysis of the charge redistribution and the electrostatic properties of the layer the overall workfunction increase can be explained.