Fluorescence investigations of pure and mixed evaporated dye layers.
Fluorescence spectroscopy is used to investigate energy transfer processes in evaporated layers consisting of several different dyes. In this study films ofN,N'-dimethylperylene-3,4∶9,10-bis-dicarboximide (methylperylene pigment, MPP), coevaporated with copper phthalocyanine (CuPc) at varying ratios, and double layers of MPP and CuPc with different thicknesses are investigated. It is shown that energy transfer from MPP to CuPc occurs in both mixed and double layers. The energy transfer leads to a strong quenching of the MPP fluorescence and sensitized CuPc emission in the NIR region. The concentration dependence of the fluorescence quenching in mixed layers can be described by a Stern-Volmer plot. A simple model based on exciton diffusion between MPP molecules toward active quenching centers is used to determine the diffusion length.
Institut für Angewandte Photophysik, Technische UniversitÄt Dresden, D-01062, Dresden, Germany.
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M
Hoffmann
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H
Böttcher