Berlin 2012 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 58: Poster Session III (Solid/liquid interfaces; Metals; Semiconductors; Oxides and insulators)

O 58.28: Poster

Mittwoch, 28. März 2012, 18:15–21:45, Poster B

Mixing Chromophores in SAMs of Azobenzene Derivatives — •Daniel Brete^{1, 2}, Daniel Przyrembel², Wolfgang Freyer¹, Robert Carley^{1, 2}, Cornelius Gahl^{1, 2}, and Martin Weinelt^{1, 2} — ¹Max-Born-Institut Berlin — ²Freie Universität Berlin

Since photoisomerisation of azobenzene-functionalised alkanethiols in self-assembled monolayers (SAMs) on gold is generally suppressed, controlled dilution of the switching moieties is desirable.

In a solution of dissimilar thiols in general one component is preferentially adsorbed leading to a single component SAM. From a solution of two similar azobenzene-functionalised alkanethiols differing only by their tail group, 6-(4-trifluoromethyl-4'-azobenzeneoxy)-hexane-1-thiol and 6-(4-cyano-4'-azobenzeneoxy)-hexane-1-thiol, we obtained mixed SAMs. HR-XPS measurements show that the composition of the SAM reflects the concentrations of the two components in solution. Shifts in the XPS peak positions indicate that real mixing and not the formation of uniform islands occurs at the surface while NEXAFS data demonstrate that the orientation of the molecules in the mixed SAM is identical to that of the single component SAMs. This is a first step towards decoupling of the chromophores.