Berlin 2012 – scientific programme
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O: Fachverband Oberflächenphysik
O 58: Poster Session III (Solid/liquid interfaces; Metals; Semiconductors; Oxides and insulators)
O 58.28: Poster
Wednesday, March 28, 2012, 18:15–21:45, Poster B
Mixing Chromophores in SAMs of Azobenzene Derivatives — •Daniel Brete1, 2, Daniel Przyrembel2, Wolfgang Freyer1, Robert Carley1, 2, Cornelius Gahl1, 2, and Martin Weinelt1, 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.