Dresden 2014 – scientific programme

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O: Fachverband Oberflächenphysik

O 36: Posters: Bio/organic Molecules on Surfaces, Graphene, Solid/liquid interfaces, Metal Substrates, Electronic Structure Theory

O 36.16: Poster

Tuesday, April 1, 2014, 18:30–22:00, P1

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

We report on the impact of potassium doping on highly-ordered ultra-thin layers of the dye molecule 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) on a Ag(111) surface under ultra-high vacuum conditions. The thin films were characterized optically by in situ differential reflectance spectroscopy (DRS) [1,2] as well as structurally by scanning tunneling microscopy (STM) and low energy electron diffraction (LEED). Depending on the doping concentration, distinct optical spectra could be observed. Except for one all could be assigned to the optical fingerprints of ionized PTCDA, showing different doping states ranging up to tetraanions. For the first three doping levels of PTCDA we were able to study the corresponding structures, which significantly differ from each other, referencing directly to the influence of the doping, i.e., doping induced phase transitions and the adsorption sites occupied by the dopants.

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.