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O: Fachverband Oberflächenphysik

O 27: Organic/bio Molecules on Metal Surfaces III

O 27.7: Vortrag

Dienstag, 1. April 2014, 12:00–12:15, TRE Phy

Structural and optical investigation of ultra-thin layers of potassium doped PTCDA on Ag(111) — •Marco Gruenewald, Christian Zwick, Roman Forker, and Torsten Fritz — Friedrich-Schiller University Jena, Institute of Solid State Physics, Max-Wien-Platz 1, Jena 07743, Germany

Here we report on the influence of potassium doping on highly-ordered ultra-thin layers of the dye molecule 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) on Ag(111). The doped thin films have been structurally characterized by LEED and LT-STM as well as optically by in-situ differential reflectance spectroscopy (DRS) [1,2]. We found that potassium doping of submonolayers of PTCDA on Ag(111) induces different highly ordered phases of PTCDA-potassium complexes depending on the doping concentration. Consequently, the electronic and thus optical characteristics of the thin film changes dramatically. For instance, by applying DRS during the film growth and the subsequent doping process we found distinct optical fingerprints which can be partially assigned to anionic features of PTCDA showing different doping stages (as investigated in detail on an inert mica substrate in ref. [3]). Furthermore, structural relaxation of PTCDA-potassium complexes due to annealing will be discussed.

References: [1] R. Forker et al., Annu. Rep. Prog. Chem., Sect. C: Phys. Chem., 2012, 108, 34-68. [2] R. Forker and T. Fritz, Phys. Chem. Chem. Phys., 2009, 11, 2142-2155. [3] T. Dienel et al., Adv. Mater., 2010, 22, 4064-4070.