Berlin 2008 – wissenschaftliches Programm
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SYSA: Symposium Tayloring Organic Interfaces: Molecular Structures and Applications
SYSA 5: Poster Session SYSA
SYSA 5.86: Poster
Dienstag, 26. Februar 2008, 14:30–20:00, Poster A
Phenyl-thiophene co-oligomer growth on dielectrics — •Frank Balzer1, Manuela Schiek1, Arne Lützen2, and Horst-Günter Rubahn1 — 1Mads Clausen Institute, NanoSYD, University of Southern Denmark, Sønderborg, Dänemark — 2Kekulé-Institute of Organic Chemistry and Biochemistry, Universität Bonn, Deutschland
Light emitting thiophene/phenylene co-oligomers have attracted quite some interest in the past due to their fortunate optical and transport properties. Here the growth of 2,5-bis(4-biphenylyl)thiophene on alkali halide (001) surfaces as well as on muscovite mica (100) is investigated by atomic force microscopy (AFM), by low energy electron diffraction (LEED), and by fluorescence microscopy. Profound differences in the growth morphology are observed. On, e.g., KCl both needle-like crystallites with several ten nanometers width and height, but several micrometers length from lying molecules are formed. These needles cover the substrate surface together with platelets from upright molecules. Needles aggregate into box-like structures with several micrometers side length. On muscovite only uniaxially aligned needles are observed by AFM and by fluorescence microscopy. However, LEED demonstrates the formation of an epitaxial wetting layer from lying molecules. In all cases needles emit polarized light after UV excitation. Formation mechanisms of such different types of self-assembled structures are discussed and compared to thin films from para-phenylenes and from α-thiophenes.