Dresden 2011 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 64: Organic Thin Films III

DS 64.2: Vortrag

Freitag, 18. März 2011, 14:15–14:30, GER 38

Interaction between Cobalt Phthalocyanine and Gold revealed by Photoexcited Electron Spectroscopies — •Fotini Petraki¹, Heiko Peisert¹, Indro Biswas¹, Umut Aygül¹, Florian Latteyer¹, Antje Vollmer², and Thomas Chassé¹ — ¹Universität Tübingen, IPTC, Auf der Morgenstelle 18, 72076 Tübingen, Germany — ²Helmholtz Zentrum Berlin für Materialien und Energie, Elektronenspeicherring BESSY II, Albert-Einstein-Str. 15, 12489 Berlin, Germany

Cobalt phthalocyanine (CoPc) monolayer films evaporated on Au(100) are studied by photoexcited electron spectroscopies (XPS, XAES, UPS, XAS, ResPES). A quite intense modification of the electronic structure of the CoPc molecule at the interface with Au, with respect to the molecule in the bulk phase, is observed by XPS, UPS and XAES (X-ray excited Auger electon spectroscopy). Local charge transfer towards the central metal atom of the phthalocyanine molecule from the gold substrate affects the charge state of the Co ion resulting in a different line shape of the Co related peaks and the presence of enhanced features in the energy region across the metal d-bands (UPS). This could be explained by a mixing of the transition metal 3d states with the underlying metallic states of gold. This suggestion is further supported by XAS data according to which, the Co 2p absorption spectra look different for monolayer and thicker organic films pointing to a possible interaction of the molecules with the substrate via the Co d- electrons. Co-related valence band states of CoPc were identified by Resonant Photoemission (ResPES).