Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 12: Organic-Inorganic Hybrid Systems and Organic Films II
O 12.5: Vortrag
Montag, 20. März 2017, 16:00–16:15, WIL A317
Structural, electronic and optical properties of K-doped PTCDA monolayer domains on Ag(111) — •M. Gruenewald1, C. Zwick1, F. Otto1, A. Baby2,3, E. Verwüster2, O. T. Hoffmann2, R. Forker1, B. Stadtmüller4, G. P. Brivio3, G. Fratesi3,5, C. Kumpf6, E. Zojer2, and T. Fritz1 — 1Institute of Solid State Physics, Friedrich Schiller University Jena — 2Institute of Solid State Physics, Graz University of Technology — 3Department of Materials Science, University of Milano-Bicocca — 4Fachbereich Physik and Research Center OPTIMAS, University of Kaiserslautern — 5Dipartimento di Fisica, Università degli Studi di Milano — 6Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich
Here we report the influence of potassium doping on highly ordered ultrathin layers of the dye molecule 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) on Ag(111). The doped thin films have been characterized by LEED, STM, PES, x-ray standing wave (XSW), and differential reflectance spectroscopy (DRS). The experimental results are consistently interpreted with the help of density functional theory (DFT) calculations. We find that potassium doping induces a structural reordering of the commensurate PTCDA herringbone phase into point-on-line structures comprising charge-transfer complexes. Their stoichiometries are determined to K2PTCDA and K4PTCDA with potassium adsorption sites nearby the anhydride groups. PTCDA appears doubly negatively charged in both complex geometries; metal-organic hybridization becomes weaker with increasing potassium concentration.