Dresden 2009 – scientific programme
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DS: Fachverband Dünne Schichten
DS 22: Organic Thin Films II
DS 22.1: Talk
Wednesday, March 25, 2009, 11:15–11:30, GER 38
Real-time detection of optical changes of diindenoperylene thin films during growth — •Ute Heinemeyer1, Reinhard Scholz2, Alexander Gerlach1, and Frank Schreiber1 — 1Institut für Angewandte Physik, Auf der Morgenstelle 10, 72076 Tübingen — 2Walter Schottky Institut, Technische Universität München, Am Coulombwall 3, 85748 Garching
Organic semiconductors have attracted increasing interest, mainly due to their potential optoelectronic applications like organic light emitting diodes and organic solar cells. Optimization of device performance requires the understanding of the underlying structure and growth behavior. Therefore, real-time measurements are particularly powerful since they detect possible changes in the functional properties already during growth. Diindenoperylene (DIP) shows a particularly well defined ordering and promising electronic transport properties together with a highly anisotropic dielectric function [1]. Differential reflectance spectroscopy (DRS), a non-invasive optical technique with high sensitivity, is used to follow the film growth of DIP on glass in the spectral range between 1.4 eV and 3.1 eV. The optical spectra show the well known vibronic progression together with an additional transition, which is related to the coupling between the molecules. The real-time growth experiments show how this additional transition arises during growth, indicating that the intermolecular coupling changes with increasing film thickness, whereas the vibronic progression is only slightly changed.
[1] U. Heinemeyer, R. Scholz et al., PRB 78, 085210 (2008)