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HL: Fachverband Halbleiterphysik

HL 9: Poster 1

HL 9.88: Poster

Montag, 23. März 2009, 14:30–17:00, P2

Measurements of absorption, fluorescence and lifetimes of Cl4MePTCDI in different solvents and crystalline phases — •Frank Friedriszik, Harald Graaf, and Christian von Borczyskowski — Center of Nanostructured Materials and Analysis, TU Chemnitz, 09107 Chemnitz, Germany

Perylene dye molecules are well know organic semiconductors with n-type behaviour. Most of the small perylene derivates consist of planar aromatic system, which leads to high molecular order in the solid state accompanied with strong intermolecular interactions. These chromophore couplings cause high electron mobility within the stack and lead to quenching of luminescence.

By chemical substitution in the bay position with chlorine a twist of the aromatic core can be found, which drastically lowers the molecular interactions. We show the changes in the photo-physical properties in solution and in the solid state using our model substance 1, 6, 7, 10-tetra-chloro-N, N'-dimethyl-perylene-tetracarboxylic-bisimide (Cl4MePTCDI). Directly after preparation an amorphous state is detected , which shows slow ordering under ambient conditions. The rate of this self-organization process depends on the temperature and is characterized by intermolecular interaction causing changes in optical absorption and luminescence. Lifetime measurements of the excited states in the crystalline and amorphous phase complete our investigations.