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O: Fachverband Oberflächenphysik
O 52: Metal substrates: Adsorption of organic / bio molecules VII
O 52.5: Vortrag
Donnerstag, 26. März 2009, 16:00–16:15, SCH A118
Investigation of meso-Tetraphenylporphyrin Molecules using Scanning Tunneling Microscopy — •Vinícius Claudio Zoldan1,2, Khalil Zakeri1, Chunlei Gao1, André Avelino Pasa2, and Jürgen Kirschner1 — 1Max Planck Institute of Microstructure Physics, Halle, Germany — 2Laboratório de Filmes Finos e Superfícies, Universidade Federal de Santa Catarina, Brazil
Due to their distinct physicochemical properties and potential for molecular architecture, porphyrins represent a group of molecules which has attracted a great technological and fundamental interest. The meso-Tetraphenylporphyrin (H2-TPP) and meso-Tetraphenylporphyrin-Cobalt II (Co-TPP) molecules were grown on Ag(111) and Cu3Au(100) substrates. In the case of Ag(111), self-organized monolayer was observed, as has been reported [1]. The growth of single molecules were achived on Cu3Au(100) at room temperature. The chemical sensitivity through bias-dependent imaging of both molecules has been measured using low temperature Scanning Tunneling Microscopy/Spectroscopy (STM/STS). The STS results show one characteristic peak near 0.6 eV for H2-TPP molecules, whereas for the Co-TPP molecules two peaks were observed at energies of -0.5 and -1.1 eV. Moreover, the dehydrogenation of the individual H2-TPP and Co-TPP molecules was realized with a local ramp-voltage from the STM tip. The energy needed for the dehydrogenation is found to be 2.0 and 3.5 eV for H2-TPP and Co-TPP, respectively.
Comanici et al. Langnuir. 24, 1897 (2008)