Regensburg 2004 – scientific programme
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SYOH: Organic and Hybrid Systems for Future Electronics
SYOH 5: Poster
SYOH 5.87: Poster
Thursday, March 11, 2004, 18:00–21:00, B
Photophysical properties of core substitution at perylene derivates — •Harald Graaf1, Harald Graaf1, Christine Mattheus2, Derck Schlettwein2, Gottfried Heinrich Bauer1, Christine Matth eus2, Derck Schlettwein2, and Gottfried Heinrich Bauer1 — 1Inst. of Physics, CvO University Oldenburg — 2Dept. of Pure and Applied Chemistry, CvO University Oldenburg
Chemical substitution in bay-position at perylene tetra carboxylic acid derivates (PTCD) e.g. by chlorine substitution leads to a twisting of the aromatic core and as a consequence influences the photophysical properties especially in the solid state. Unlike the unsubstituted PTCD, however, thin films (≈ 30nm) of the bay-chlorinated Cl4PTCD showed almost no chromophore coupling, directly measured by optical absorption spectroscopy. The formation of excimers is prevented so that an emission from uncoupled monomers could be found in a quantum efficiency comparable to that in solution. Also the arrangement of the molecules in the film is influenced by the hindered coupling which was seen in an unstructured morphological configuration measured by AFM. In thicker films ( ≥ 100 nm) a slow ordering process was observed and an excimer formation could be obtained. More over we have prepared monolayers of substituted molecules by covalent bounding at a modified glass surface in order to study two- dimensional intermolecular interactions.