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DS: Fachverband Dünne Schichten

DS 4: Organic Thin Films

DS 4.2: Talk

Monday, February 25, 2008, 16:30–16:45, H 2013

Charged Molecules on Insulators: Optical Spectroscopy of PTCDA Ions — •Thomas Dienel, Andreas Krause, Roman Forker, and Torsten Fritz — Institut für Angewandte Photophysik, Technische Universität Dresden, 01062 Dresden, Germany

It has been shown that the performance of organic-based devices can be improved considerably by doping [1]. However, on the molecular scale the mechanisms of doping are still not fully understood. Here, optical spectroscopy comes in handy as valuable tool for material characterization. By applying in situ optical spectroscopy to (sub-)monolayer thick organic films during the actual doping process, insight in the successive development of the charged states can be gained.

In our contribution we present differential reflectance spectroscopy (DRS) [2] on perylene-3,4,9,10-tetracarboxylic-dianhydride (PTCDA) layers doped by potassium. From the spectral development with increasing potassium concentration we conclude the occurrence of different charged states and give reasons for their assignment.

[1] K. Walzer et al., Chem. Rev. 107 (2007), 1233.

[2] H. Proehl et al., Phys. Rev. B 71 (2005), 165207.