Regensburg 2007 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 58: Metal Substrates: Adsorption IV
O 58.2: Vortrag
Donnerstag, 29. März 2007, 16:00–16:15, H39
Tuning the interaction of fullerenes with metal surfaces by molecular self-assembly — •Katharina Jennifer Franke1, Gunnar Schulze1, Isabel Fernández-Torrente1, Nils Henningsen1, Sebastian Zarwell2, Karola Rück-Braun2, Nicolás Lorente3, and José Ignacio Pascual1 — 1Freie Universität Berlin, Fachbereich Physik, Germany — 2Technische Universität Berlin, Institut für Chemie, Germany — 3Université Paul Sabatier, Toulouse, France
Frequently, thin insulating layers are used to electronically decouple molecules from metallic substrates. In an alternative approach we show here, that intermolecular interactions can be employed to create supramolecular structures, which decrease the electronic coupling of fullerenes to a metallic substrate. By low-temperature scanning tunnelling microscopy (STM) we find that the co-adsorption of molecular tripods (1,3,5,7-tetraphenyladamantane) and fullerenes on Au(111) leads to the formation of two basic self-assembled building blocks, which hierarchically arrange in larger structures. One of them is a triangular shaped tetramer consisting of three tripods with a C60 in their centre. The second one results in rows of alternating adamantane and fullerenes. In both cases scanning tunnelling spectroscopy shows that the presence of the tripod linkers modify the electronic configuration of the fullerene cage. In particular, the tunnelling spectra show a negative differential resistance characteristic for a weaker electronic coupling to the Au(111). DFT calculations indicate that the tripods lift the C60 from the surface, thus allowing the tunability of the fullerene-metal interaction.