Berlin 2012 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 35: Organic thin films III: Monolayers and crystals

DS 35.2: Vortrag

Donnerstag, 29. März 2012, 18:00–18:15, H 2032

Organic heteroepitaxy of PTCDA and SnPc on single crystalline silver — •Marco Gruenewald, Kristin Wachter, Falko Sojka, Matthias Meissner, 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). The thin films were characterized optically by in situ Differential Reflectance Spectroscopy (DRS), followed by an extraction of the related optical constants.

For the first monolayer PTCDA and the first monolayer SnPc the well-known covalent interaction [1] between adsorbate and substrate is manifested in broad and structureless absorption spectra. Further layers of PTCDA and SnPc, however, are efficiently optically decoupled from the first monolayer. Hence, a monomer signature for the respective molecules is observed until aggregation occurs. In the first monolayer of PTCDA on top of a SnPc monolayer film the coexistence of neutral and anionic PTCDA is concluded. Furthermore, SnPc on top of a PTCDA and on top of a SnPc monolayer was investigated optically. Accordingly, the existence of a PTCDA interlayer induces a highly-ordered growth of SnPc up to several monolayers.

REFERENCES

[1] M. Häming et al., Phys. Rev. B 82, 235432 (2010).