Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 41: Poster Session I (Semiconductor Substrates: Epitaxy and growth; Semiconductor Substrates: Adsorbtion; Semiconductor Substrates: Solid-liquid interfaces; Semiconductor Substrates: Clean surfaces; Oxides and insulators: Epitaxy and growth; Oxides and insulators: Adsorption; Oxides and insulators: Clean surfaces; Organic, polymeric and biomolecular films - also with adsorbates; Organic electronics and photovoltaics, Surface chemical reactions; Heterogeneous catalysis; Phase transitions; Particles and clusters; Surface dynamics; Surface or interface magnetism; Electron and spin dynamics; Spin-Orbit Interaction at Surfaces; Electronic structure; Nanotribology; Solid/liquid interfaces; Graphene; Others)

O 41.34: Poster

Dienstag, 23. März 2010, 18:30–21:00, Poster B1

Self-assembled monolayers on gold containing azobenzene ligands — •Robert Ossig¹, Florian Vogel¹, Frauke Bretthauer², Ulrich Siemeling², and Frank Träger¹ — ¹Institut für Physik and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), Universität Kassel, Kassel, Germany — ²Institut für Chemie and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), Universität Kassel, Kassel, Germany

Self-assembled monolayers (SAMs) of photoresponsive molecules yield a wide range of applications, for example, for optical devices. At present the SAMs usually consist of small anchor groups based on symmetric disulfids or thiols and large functional groups. However, the densely packed arrangement of these molecules on substrates causes a steric hindering for photoisomerisation. Hence, larger anchor groups or molecules with more than one anchor group are necessary to provide more space between the functional groups. For this purpose we have recently synthesised molecules consisting of a photoresponsive functional and two anchor groups. The functional group is based on azobenzene-derivatized 1,2-dithiolanes which can be switched between their cis and trans isomers. In this contribution we present fundamental adsorption studies of these molecules and the SAM formation, investigated by means of optical second harmonic generation. We demonstrate that for a concentration of 50 µmol/l the second order Langmuir kinetics describes the adsorption best. For a deeper insight of the involved processes concentration dependent measurements as well as ellipsometry and scanning-tunnelling microscopy have been conducted.