Regensburg 2019 – scientific programme

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DS: Fachverband Dünne Schichten

DS 16: Organic Thin Films, Organic-Inorganic Interfaces

DS 16.5: Talk

Wednesday, April 3, 2019, 10:30–10:45, H39

Reaction of Calcium with Tetraphenylporphyrin Thin Films: Reaction Energies and Reaction Depths — •Maik Schöniger, Stefan Renato Kachel, Claudio K. Krug, Tabea Koehler, Martin Schmid, and J. Michael Gottfried — Philipps-Universität Marburg, Fachbereich Chemie, Hans-Meerwein-Str. 4, 35032 Marburg

We have investigated the interface reaction of vapour-deposited calcium (Ca) with tetraphenylporphyrin (2HTPP) thin films (20-30 nm) by means of Hard X-Ray Photoemission Spectroscopy (HAXPES) and Nanojoule Adsorption Calorimetry (NAC). The importance of low work-function materials and organic semiconductors is obvious as they are commonly used in organic electronics. However, their interfacial interactions are poorly understood. Clarifying diffusion and reaction processes occurring during metal deposition onto the organic material is crucial for a deeper understanding of the performance of such systems. The Ca/2HTPP system is a model system that allows us to study the energetics of a typical interface reaction and to establish concentration depth profiles of the resulting interphase layer, which here consists of the reaction product CaTPP. Using HAXPES, we measured depth profiles of the interface region for different preparation conditions of the interface. Parameters such as temperature or flux of the Ca atoms were varied. As complementary data, we will report enthalpies of adsorption and reaction, measured using NAC coupled with a pulsed Ca atomic beam source. The apparatus allows the direct measurement of these quantities, which cannot be obtained by temperature-programmed desorption or similar frequently used methods.