Regensburg 2013 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 31: Organic thin films II

DS 31.1: Vortrag

Donnerstag, 14. März 2013, 14:45–15:00, H8

Organic heteroepitaxy of PTCDA and SnPc on single crystalline metals — •Marco Grünewald, Kristin Wachter, Roman Forker, and Torsten Fritz — University of Jena, Institute of Solid State Physics, Max-Wien-Platz 1, 07743 Jena, Germany

Here we report on the interaction mechanisms at metal-organic and organic-organic interfaces in heterostructures of highly-ordered ultrathin layers of the dye molecules 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) and tin(II)-phthalocyanine (SnPc) on Ag(111) and Au(111). The thin films were structurally characterized by Low Energy Electron Diffraction (LEED) and Scanning Tunneling Microscopy (STM) as well as optically by in situ Differential Reflectance Spectroscopy (DRS). For the first monolayer PTCDA and the first monolayer SnPc we observe significant differences between the dielectric functions extracted from the DRS depending on the substrate used indicating a rather different nature of metal-organic interaction. From the structural point of view an one monolayer SnPc film on top of Au(111) arranges as a highly ordered layer with a quadratic unit cell in a point-on-line coincidence with the reconstructed Au(111) surface. PTCDA grown on top of the first SnPc layer, however, decouples from the substrate as well as from the interlayer and shows a spectral monomer-like behavior. Structural investigations indicate an ordered growth with a line-on-line coincidence between the PTCDA and the SnPc interlayer. Additional new spectral features in the optical spectra on both substrates have been observed which can be explained by a vertical compression of the organic layer in contact with the substrate.