Dresden 2009 – scientific programme
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DS: Fachverband Dünne Schichten
DS 23: Organic Thin Films III
DS 23.4: Talk
Wednesday, March 25, 2009, 15:30–15:45, GER 38
Structure and Lateral Conduction in a monolayer of molecular nanographenes — •Asif Bashir1, Carsten Busse1,2, Xi Dou3, Daniel Käfer1, Zhihong Wang1, Gregor Witte1,4, Klaus Müllen3, and Christof Wöll1 — 1Lehrstuhl für Physikalische Chemie I, Ruhr-Universität Bochum, Germany — 2Physikalisches Institut, Universität zu Köln, Germany — 3Max Planck Institute for Polymer Research Mainz, Germany — 4AG Molekulare Festkörperphysik, Philipps-Universität Marburg, Germany
The molecular nanographenes hexa-peri-hexabenzocoronene (HBC) and HBC-derivatives can self-assemble in form of columnar film structures, which have recently attracted a paramount interest in connection with one-dimensional charge transport. The fabrication of such columnar system was carried out by using thiolated HBC-derivates, where one-dimensional monomolecular columns are formed by the self organization of HBC molecules modified by thiol (-SH) anchors upon adsorption on Au(111) substrates. The HBC self-assembled monolayer (SAMs) are found to form long range ordered domains consisting of equidistant paired rows with closely stacked HBC units. Data from scanning tunneling microscopy (STM) and near-edge x-ray absorption spectroscopy (NEXAFS) allows to derive a detailed structural model. The charge transport along the columns within the SAM is investigated by embedding the thiolated HBC-derivates into a matrix of alkanethiols (C10-SH). The temperature dependence of apparent height on the HBC-thiol-islands and the electronic coupling between closely packed aromatic molecules exhibited by the lateral transport will be presented.