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O: Fachverband Oberflächenphysik

O 6: Poster Session I: Organic molecules on inorganic substrates: Adsorption and growth I

O 6.5: Poster

Monday, March 1, 2021, 10:30–12:30, P

Layer stability of porphyrin molecules on TiO2(110) — •Maximilian Muth, Alexander Wolfram, Elmar Kataev, Julia Köbl, Hans-Peter Steinrück, and Ole Lytken — Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander Universität Erlangen- Nürnberg, Germany

Understanding the adsorption properties of organic molecules to substrate surfaces is of essential importance for applications. Typically, the adsorption energy of a smaller molecule to a surface can be determined by TPD. However, for large organic molecules only desorption of the multilayers is possible while the bottom monolayer in direct proximity to the surface cannot be desorbed without decomposition. But usually, especially the adsorption energies of these directly adsorbed molecules are the ones of the most interest. To overcome this problem we use a method including XPS with which we can determine the binding strength of differently metalated tetraphenyl porphyrins to a rutile TiO2(110) surface comparatively to each other. Therefore, a layer exchange between two differently metalated tetraphenyl porphyrins with subsequent desorption of the multilayers is caused by an annealing ramp. The composition of the residual monolayer is investigated by XPS. By using the ratios of the two porphyrins in the residual monolayer, we can estimate the difference in binding energy between the two porphyrins over a calculation of the equilibrium constant of the layer exchange process.