Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 14: Metal substrates: Adsorption of organic / bio molecules II

O 14.6: Vortrag

Montag, 22. März 2010, 16:15–16:30, H36

Adsorption of long-chain alkanethiols on Au(111): a look from the substrate side — •Frederick Chesneau¹, Jianli Zhao¹, Cai Shen², Manfred Buck², and Michael Zharnikov¹ — ¹Angewandte Physikalische Chemie, Universität Heidelberg, Germany — ²EaStCHEM School of Chemistry, University of St Andrews, UK

The structure of interface between a self-assembled monolayer (SAM) of alkanethiolates and the underlying Au(111) substrate is one of the greatest mysteries of surface science. To cast light on this problem, we took SAMs of hexanethiolate (HT) and dodecanethiolate (DDT) on Au(111) as test systems and studied them by a combination of synchrotron-based high resolution X-ray photoelectron spectroscopy (HRXPS) and scanning tunneling microscopy (STM). The emphasis of the HRXPS characterization was put on the Au 4f emission of the substrate, which could be decomposed into the components related to the bulk and surface. The behavior of the surface component upon the formation of HT and DDT SAMs was monitored in detail. We observed both a shift of this component and its branching into two independent emissions, which were associated with the gold atoms in the topmost layer and gold adatoms, respectively. The branching of the surface component was correlated with the lateral structure of the SAMs as determined by STM. Conclusions on the reliability of different adsorption models for these lateral structures were derived.