Berlin 2018 – scientific programme
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O: Fachverband Oberflächenphysik
O 104: Oxides and Insulators: Adsorption I
O 104.2: Talk
Thursday, March 15, 2018, 17:00–17:15, MA 041
Covalent Anchoring and Interfacial Reactions of Adsorbed Porphyrins on TiO2(110) — •Daniel Wechsler1, Cynthia Fernández2, Hans-Peter Steinrück1, Ole Lytken1, and Federico Williams2 — 1Chair of Physical Chemistry II, University Erlangen-Nürnberg, 91058 Erlangen, Egerlandstraße 3, Germany — 2Department of Inorganic, Analytical and Physical Chemistry, University of Buenos Aires, Buenos Aires C1428EHA, Argentina
Understanding the bonding between organic molecules and metal-oxide surfaces plays an important role in many nanotechnology devices. Functional groups, like -COOH, can act as linkers to attach molecules to surfaces in a controlled manner. We have studied the adsorption and covalent anchoring of 5-monocarboxyphenyl-10,15,20-triphenylporphyrin (MCTPP) on TiO2(110) with X-ray Photoelectron Spectroscopy. At elevated temperatures, the free-base porphyrin molecules metalate on the surface, forming what we expect to be titanyl (Ti=O) porphyrin. The reaction is strongly coverage-dependent with lower coverages metalating at lower temperatures, possible caused by flat-lying molecules at low coverages being in closer proximity to the surface. We also find the metalation of porphyrins exposed to Zn2+ ions in solution to depend on the porphyrin coverage on the TiO2(110) surface, but the effect is less pronounced.
The project is supported by the DFG trough FOR 1878 (funCOS).