Berlin 2012 – scientific programme
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O: Fachverband Oberflächenphysik
O 44: Focussed session: Functional molecules at surfaces II
O 44.5: Talk
Wednesday, March 28, 2012, 12:00–12:15, A 053
Photoswitching of Molecular Platform Adlayers — •Ulrich Jung1, Sonja Kuhn1, Mathias Müller1, Sandra Ulrich2, Jens Kubitschke2, Rainer Herges2 und Olaf Magnussen1 — 1Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Leibnizstr. 19, 24118 Kiel, Germany — 2Otto-Diels-Institut für Organische Chemie, Christian-Albrechts-Universität zu Kiel, Otto-Hahn-Platz 4, 24098 Kiel, Germany
We have recently introduced a novel approach for preparation of adlayers with freestanding functional groups on metal surfaces based on customizable molecular platforms and characterized the structure of these adlayers by scanning tunneling microscopy [1,2,3] and various spectroscopies [4]. The adlayers were found to exhibit a high degree of order with the functionalities oriented in a defined way with respect to the surface and precisely controlable vertical and lateral distances.
Here, we will focus on photoswitching properties of platform adlayers exhibiting azobenzene functionalities. Generally, photoswitching is preserved upon formation of such adlayers, the according reactions follow first-order kinetics with high quantum efficiencies of ≈ 10−4. In addition, thermal backswitching is found to proceed several orders of magnitude faster in the adlayers than in solution, which can be attributed to pronounced electronic coupling of the azobenzene functionalities with the metal substrate.
[1] Baisch et al., J. Am. Chem. Soc. (2009), 131, 442, [2] Kuhn et al. PCCP (2010), 12, 4481, [3] Kuhn et al, Chem. Commun. (2011), 47, 8880, [4] Jung et al., Langmuir (2011), 27, 5899