Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 25: Metal substrates: Adsorption of organic / bio molecules III

O 25.4: Vortrag

Dienstag, 23. März 2010, 11:15–11:30, H36

Dynamics of Tetraphenylporphyrins on a Copper (111) surface: A Scanning Tunneling Microscopy Study — •Stefanie Gläßel, Florian Buchner, Elisabeth Zillner, Michael Röckert, Hans-Peter Steinrück, and Hubertus Marbach — Lehrstuhl für Physikalische Chemie II and Interdisciplinary Center for Molecular Materials (ICMM), Universität Erlangen-Nürnberg, Egerlandstr. 3, D-91058

The understanding of the properties of large organic molecules at surfaces is a requirement to utilize their functional properties either in single-molecule devices or in organized supramolecular architectures. Here we concentrate on the investigation of the dynamics and self-assembly of tetraphenylporphyrins (TPP) on Cu(111) using scanning tunneling microscopy (STM) in ultra-high vacuum (UHV). STM images of ordered molecular arrays and individual molecules with submolecular resolution enable to determine the supramolecular and intramolecular conformation of the porphyrins. Interestingly, 2HTPP molecules exhibit a mainly one dimensional diffusion along the main crystallographic axes of Cu(111) at room temperature, whereas CoTPP molecules form ordered arrays. Based on STM movies acquired at varying sample temperatures fundamental parameters of the molecular motion of 2HTPP on Cu(111), like the activation energy for diffusion and rotation could be estimated. These results allow a deeper understanding of the corresponding molecule-molecule and molecule-substrate interactions and thus the assembly of the observed porphyrins.

Funded by the DFG through Sonderforschungsbereich 583.