Dresden 2017 – scientific programme
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O: Fachverband Oberflächenphysik
O 29: Organic-Inorganic Hybrid Systems and Organic Films IV
O 29.10: Talk
Tuesday, March 21, 2017, 12:45–13:00, WIL A317
Wavelength sensitivity of the photostationary state of azobenzene-functionalized SAMs — •Wibke Bronsch, Larissa Boie, Cornelius Gahl, and Martin Weinelt — Freie Universität Berlin, Deutschland
Azobenzene is a molecular switch with significantly different static dipole moments in its trans and cis isomer, respectively. Embedded in self-assembled monolayers (SAMs), this property can be used for real-time tuning of the sample work function. A specific work function is hence a measure of a particular photostationary state (PSS) of the SAM. In this contribution we investigate the PSS of azobenzene-functionalized undecane thiol diluted with dodecanethiol on Au(111). Work function variations are monitored by means of two-photon photoelectron spectroscopy. We show that the PSS is very sensitive to the illumination wavelength when tuned across the S2 absorption band of the 2-dimensional molecular aggregate. Due to the interplay of the different absorption cross sections and quantum yields of the two isomers, the PSS changes from mainly trans to mainly cis in the range of 300 to 370 nm.