Dresden 2011 – scientific programme
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O: Fachverband Oberflächenphysik
O 75: Metal substrates: Adsorption of organic / bio molecules VIII
O 75.2: Talk
Thursday, March 17, 2011, 15:15–15:30, PHY C213
Reversible switching of ex-situ surface mounted molecular switches probed by laser-based photoemission. — •Nils Heinemann1, Jan Grunau1, Till Leißner1, Sonja Kuhn1, Dordaneh Zargarani2, Ulrich Jung1, Oleksiy Andreev1, Rainer Herges2, Olaf Magnussen1, and Michael Bauer1 — 1Inst. f. Exp. u. Angew. Phys., Uni Kiel — 2Inst. f. Org. Chem., Uni Kiel
Molecular electronics hold the potential as boom town of nanotechnology. The controlled manipulation of molecular switches adsorbed on surfaces is a key prerequisite to advance into more sophisticated applications. In this contribution we will present a photoemission study of the molecular switch 3-(4-(4-Hexylphenylazo)-phenoxy)-propan-1-thiol adsorbed on Au(111) single crystal (1/Au).
This molecule undergoes trans-cis isomerisation upon absorption of UV light (365 nm), the back-isomerisation is induced by absorption of blue light (440 nm) or thermal activation. With regard of application, we chose an ex-situ preparation for the experiments, i. e. deposition from solution. The switching behavior of these samples was investigated with photoemission spectroscopy under UHV conditions, using the forth harmonic laser light of a tuneable 80 MHz fs-laser system.
In our study we were able to follow the reversible switching between the trans- and the cis-isomere of 1/Au, induced by photo-thermal and photo-photo stimulation. The quantitative analysis of our data show that only a minor fraction of the adsorbed molecules undergo a switching indicating the potential relevance of substrate and/or film defects in this process.