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DS: Fachverband Dünne Schichten
DS 4: Organic Electronics and Photovoltaics II (Joint Session DS/CPP/HL/O)
DS 4.6: Vortrag
Montag, 22. März 2010, 15:15–15:30, H8
A high molecular weight donor for electron injection interlayers on metal electrodes — •Benjamin Bröker1, Ralf-Peter Blum1, Luca Beverina2, Oliver T. Hofmann3, Georg Heimel1, Antje Vollmer4, Johannes Frisch1, Jürgen P. Rabe1, Egbert Zojer3, and Norbert Koch1 — 1Institut für Physik, Humboldt-Universität zu Berlin, Newtonstrasse 15, D-12389 Berlin, Germany — 2Department of Materials Science and INSTM, State University of Milano-Bicocca, Via Cozzi 53,I-20125 Milano, Italy — 3Institute of Solid State Physics, Graz University of Technology, Petersgasse 16, A-8010 Graz, Austria — 4Helmholtz-Zentrum Berlin, Bessy II, Albert-Einstein-Str. 15, D-12489 Berlin, Germany
The molecular donor 9,9-ethane-1,2-diylidene-bis(N-methyl-9,10-dihydroacridine) (NMA) has been synthesized, and its electronic properties were characterized at interfaces to metals with photoelectron spectroscopy. Here a decrease of the sample work function is observed that becomes larger with increasing molecular coverage and clearly exceeds values that would be expected for metal surface electron "push back" alone, confirming the electron donating nature of NMA. For tris(8-hydroxyquinoline)aluminum (Alq3) deposited on top of a NMA-modified Au(111) surface, the electron injection barrier (EIB) is reduced by 0.25 eV compared to that on pristine Au(111). Furthermore, the EIB reduction depends linearly on Θ of the donor-modified Au(111) surface, adjustable by NMA pre-coverage. Comparisons will also be given to the stronger donor MV0.
This work was supported by the EC project ICONTROL.