title: UV/Vis Spectroscopy Studies of the Photoisomerization Kinetics in Self-Assembled Azobenzene-Containing Adlayers.
abstract: Direct comparative studies of the photoisomerization of azobenzene derivatives in self-assembled adlayers on Au and as free molecules in dichloromethane solution were performed using UV/vis spectroscopy. For all studied systems a highly reversible trans-cis isomerization in the adlayer is observed. Quantitative studies of the absorbance changes and photoisomerization kinetics reveal that in azobenzenes mounted as freestanding vertical groups on the surface via triazatriangulene-based molecular platforms photoswitching is nearly uninhibited by the local environment in the adlayer. The blue-shift of the π-π* transition in adlayers of these molecules is in good agreement with theoretical studies of the effect of excitonic coupling between the molecules. In contrast, in azobenzene-containing thiol self-assembled monolayers the fraction of photoswitching molecules and the photoisomerization kinetics are significantly reduced compared to free molecules in solution.
authors.affiliation: †Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Leibnizstr. 19, 24118 Kiel, Germany.
authors.forename: N R
authors.initials: NR
authors.lastname: Krekiehn
authors.affiliation: †Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Leibnizstr. 19, 24118 Kiel, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Müller
authors.affiliation: †Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Leibnizstr. 19, 24118 Kiel, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Jung
authors.affiliation: ‡Otto-Diels-Institut für Organische Chemie, Christian-Albrechts-Universität zu Kiel, Otto-Hahn-Platz 4, 24098 Kiel, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Ulrich
authors.affiliation: ‡Otto-Diels-Institut für Organische Chemie, Christian-Albrechts-Universität zu Kiel, Otto-Hahn-Platz 4, 24098 Kiel, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Herges
authors.affiliation: †Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Leibnizstr. 19, 24118 Kiel, Germany.
authors.forename: O M
authors.initials: OM
authors.lastname: Magnussen