Dresden 2003 – wissenschaftliches Programm

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DS: Dünne Schichten

DS 24: Poster

DS 24.40: Poster

Dienstag, 25. März 2003, 14:30–17:00, P2a

Video-microscopy of crystal growth of tetracene in thin liquid films — •Sylvia Dorsfeld, Michael Voigt und Moritz Sokolowski — Institut für Physikalische und Theoretische Chemie, Universität Bonn, Wegelerstr. 12, D-53115 Bonn

Tetracene vapour deposited onto a thin liquid film of bis(2-ethylhexyl) sebacate forms very large (several 100 µ m diameter) thin crystals, perfectly oriented with their (001) plane parallel to the substrate. The growth occurs quasi-2dimensional in the film plane. The details of the growth kinetics were studied by in-situ video polarisation microscopy as a function of the deposition rate and liquid film thickness. In agreement with classical nucleation theory, the saturation number density of the nuclei increases with increasing deposition rate, indicating a homogenous nucleation in a highly supersaturated liquid. For high deposition rates, pronounced dendritic growth occurs, whereas for small rates, pallet shaped compact crystallites with equilibrium facets are observed. Possibilities to use this growth technique for the preparation of high quality organic films are discussed. Supported by the DFG.