Regensburg 2007 – scientific programme

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O: Fachverband Oberflächenphysik

O 16: Organic, Polymeric, and Biomolecular Films I

O 16.5: Talk

Monday, March 26, 2007, 15:15–15:30, H42

Microscopic Identification of Different Porphyrin Species in Composite Layers — •Florian Buchner, Veronika Schwald, Karmen Comanici, Ken Flechtner, Sven Schöffel, Thomas Lukasczyk, Michael Gottfried, Hubertus Marbach, and Hans-Peter Steinrück — Lehrstuhl für Physikalische Chemie II, Universität Erlangen-Nürnberg, Egerlandstraße. 3,

The self-assembly of organic molecules on single crystal surfaces is an approach towards the creation of novel materials with outstanding properties. Porphyrins represent a group of molecules, which are of great interest for various applications and also for basic science. In this study, composite films of different mixtures of the free-base 2H-5,10,15,20-Tetraphenylporphyrin (2HTPP) and Metallo-TPPs (namely FeTPP and CoTPP) were prepared on Ag (111), and imaged in UHV using scanning tunnelling microscopy (STM). A novel preparation method was applied by in-situ deposition of iron atoms onto the 2H-TPP monolayer. Microscopic evidence for the successful complexation of 2HTPP with Fe will be given [1]. This method is now also exploited to fabricate composite layers with 2HTPP, CoTPP and FeTPP. Depending on the bias voltage, the different molecules appear as protrusions or depressions, with changing shapes. Considering the different electronic configurations and additional UPS measurements, the different porphyrins can be identified.

[1] Buchner et al., ChemPhysChem (in press) This work has been funded by Sonderforschungsbereich 583