Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 31: Molecular Films: Properties and Preparation
O 31.5: Vortrag
Dienstag, 1. April 2014, 11:30–11:45, WIL A317
Core-Level Spectroscopy Studies on Self-Assembly and Switching of Mixed Azobenzene Monolayers — •Daniel Przyrembel1, Thomas Moldt1, Daniel Brete1, Joel R. Goldman2, Rafal Klajn2, Cornelius Gahl1, and Martin Weinelt1 — 1Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin — 2Department of Organic Chemistry, Weizmann Institute of Science, 76100 Rehovot, Israel
We have prepared mixed self-assembled monolayers (SAMs) containing photochromic azobenzene derivatives.[1] Besides this, our approach allows creating layers of, e.g., an 11-(4-(phenyldiazenyl)phenoxy)alkyl-1-thiol diluted with a C12 alkane thiol on Gold(111) substrates from solution in a controlled way. Like this we obtained monolayers with tuneable packing density of the azobenzene units that are stable and durable under ambient conditions. Moreover, the attained increase in free volume around the chromophores in combination with efficient decoupling from the substrate yields reversibly switchable SAMs, responsive to ultraviolet and visible light. Here we present our results from investigating by means of core-level spectroscopies the self-assembly process and the photoswitching. The samples exhibit a complex mixing behaviour with preferential adsorption of one component; and we observed a changing degree of ordering depending on the time the samples are immersed during preparation. The measured changes due to photoswitching vary for different surface component ratios.
[1] D. Brete, D. Przyrembel, C. Eickhoff et al. J. Phys.: Condens. Matter 24, 394015 (2012).