Regensburg 2016 – scientific programme

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DS: Fachverband Dünne Schichten

DS 4: Organic Thin Films I

DS 4.8: Talk

Monday, March 7, 2016, 11:45–12:00, H11

Structure and thermal stability of dithiol SAM on Au(111) — •Johannes Völkner and Gregor Witte — AG Molekulare Festkörperphysik, Philipps-Universität Marburg

Self-assembling monolayers (SAMs) are commonly used for molecular modification of metal surfaces. It results in a variation of surface properties such as wetting behavior, friction, reactivity and biocompatibility. In this study an Au(111) surface is functionalized with aromatic trans-stilbene dithiol by means of wet-chemical preparation. While one thiol moiety binds to the surface under thiolate formation the opposite one stays intact. Latter terminates the self-assembling monolayer and thus enables binding events on top of the film. This was for instance recently exploited in a biosensor application based on photoexcitation of quantum dots [1].

Efficient coupling of additional layers however requires high stability and packing density of the film. We prepared stilbene dithiol SAMs under different conditions and verified intactness of the terminating group by means of XPS. Complementary, structural order was investigated in NEXAFS measurements. A clear alteration of the films upon annealing was identified and related to thermal desorption spectra.

[1] N. Sabir et al., Small 11, 5844 (2015)