Dresden 2009 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 37: Metal substrates: Adsorption of organic / bio molecules V
O 37.6: Vortrag
Mittwoch, 25. März 2009, 16:15–16:30, SCH A118
Formation of azobenzene containing self-assembled monolayers on gold monitored by optical second harmonic generation — •Florian Vogel1, Mario Meier2, 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
The azobenzene derivative Bis[4-(phenylazo)phenyl]disulfide was synthesized and used for the preparation of self-assembled monolayers (SAM) on gold substrates. Azobenzene derivatives can be switched between their “cis” and “trans” isomers by irradiation with light. This molecular system, which is an ideal candidate for photoswitchable devices, represents the most widely studied system for SAMs bearing photoactive functional units.
The adsorption dynamics of the molecules have been investigated in situ and in real time by optical second harmonic generation (SHG). It has been shown that the adsorption of the molecules on the gold substrate can be well described by second order Langmuir kinetics.
Additional ellipsometric measurements have confirmed that, in fact, a monolayer of the molecules has been formed. The thickness was determined to be (12 ± 1) Å. This is in good agreement with the theoretical value.