Dresden 2009 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 23: Organic Thin Films III
DS 23.2: Vortrag
Mittwoch, 25. März 2009, 15:00–15:15, GER 38
Correlating bonding distance and interfacial electronic structure: The role of molecular side groups — •Steffen Duhm1,2, Alexander Gerlach3, Georg Heimel1, Benjamin Bröker1, Takuya Hosokai3, Tien-Lin Lee4, Jens Pflaum5, Satoshi Kera2, Nobuo Ueno2, Frank Schreiber3, and Norbert Koch1 — 1Humboldt-Universität zu Berlin, Germany — 2Chiba University, Japan — 3Universität Tübingen, Germany — 4European Synchrotron Radiation Facility, Grenoble, France — 5Universität und ZAE Würzburg, Germany
The interplay of energy level alignment and bonding distance of conjugated organic adsorbates on metal substrates is not yet fully understood. We studied the interfaces formed between pentacene (PEN) and its oxo-derivatives pentacenequinone (PQ) and pentacenetetrone (PT) on Ag(111) using X-ray standing waves (XSW) and ultraviolet photoelectron spectroscopy (UPS). A strong correlation could be found between the XSW and UPS results: The interaction of PEN and PQ with Ag(111) is rather weak, which is reflected in larger bonding distances and almost identical electronic structures for mono- and multilayer. In contrast, PT is strongly chemisorbed on Ag(111) through a charge transfer reaction leading to a metallic monolayer and a partial filling of the lowest unoccupied molecular orbital. This strong interaction results in a rather low bonding distance of PT on Ag(111) and an additional bending of the oxygen atoms towards the metal substrate.