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O: Fachverband Oberflächenphysik

O 111: Oxides and Insulators: Adsorption II

O 111.6: Talk

Friday, March 16, 2018, 11:45–12:00, MA 041

Measuring Heats of Adsorption of Porphyrins on Oxide Single-Crystal Surfaces — •Ole Lytken, Quratulain Tariq, Daniel Wechsler, Matthias Franke, and Hans-Peter Steinrück — Universität Erlangen-Nürnberg, Germany

Porphyrins are large organometallic complexes interesting for a variety of applications such as organic electronics and solar cells. For many of these applications the interface between the porhyrins and the substrate they are deposited on is particularly interesting. However, determining the heats of adsorption of porphyrins on surfaces is not straight forward: theoretical calculations have to include van der Waals interactions, and experimental measurements have to consider decomposition of the monolayer simultaneous with desorption. In this study we present temperature-programmed desorption (TPD) measurements of three porphyrins, CoTPP, ZnTPP and MgTPP, from an Mgo(100) surface. To reduce the influence of decomposition, which may affect the shape of the desorption peak, we use simple Redhead analysis. The accuracy of Redhead analysis depends critically on the chosen prefactor, and we use the prefactor derived from desorption of multilayers.