Berlin 2012 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 16: Organic electronics and photovoltaics: simulations and optics II (jointly with CPP, HL, O)
DS 16.4: Vortrag
Dienstag, 27. März 2012, 12:15–12:30, H 2032
Stability of perfluroro-pentacene thin films on coinage metals — •Christian Schmidt1, Tobias Breuer1, Stefan Wippermann2, Wolf Gero Schmidt2, and Gregor Witte1 — 1Molekulare Festkörperphysik, Philipps-Universität Marburg, Germany — 2Theoretische Physik, Universität Paderborn, Germany
The development of organic electronics greatly benefits from the systematic improvement of molecular properties by chemical functionalization. One example constitutes pentacene that can be prevented from oxidization by perfluorination. Topical investigations of the interface properties of perfluoropentacene (PFP) are frequently conducted only from an electronic point of view, measuring either macroscopic device properties or valence band spectra. In these studies possible chemical interactions have not been addressed since PFP is especially designed to be more stable than PEN. It was therefore unexpected that PFP monolayers on Cu(111) undergo degradation upon heating and that decomposition also occurs on Ag(111). This means that PFP is less stable than PEN, which desorbs intact from Ag(111). This behaviour is especially remarkable when considering that PFP is farther above metal surfaces than PEN. This unclear situation is very problematic, as the PFP-metal interface itself serves as a model system for electronic effects and is of vital interest in this field. Therefore, we systematically studied the thermal behaviour of PFP on the coinage metals by means of temperature NEXAFS and XPS. In order to understand underlying mechanisms we accompany our experimental data with density functional theory (DFT) calculations including chemical reactions.