Die Konzentrationsabhängigkeit der Energie-Übertragung in Anthracen-Tetracen-Mischkristallen

Abstract

The relative quantum yields of the host and guest fluorescence in anthracene-tetracene mixed crystals have been measured for tetracene concentrations cT between 10-6 and 10-1 mol/mol and temperatures below and above the temperature region, where the energy transfer is partially quenched by shallow traps (35°K) . The concentration dependence of the quantum ratio is measured as QT/QA = k • cTp, where the exponent p is nearly 1 and k is measured as 6 · 104 and explained as the ratio τW/tH (τW is the decay time of the host fluorescence and tH the hopping time) . The fraction of transfer which is quenched at lowest temperatures is independent of the tetracene concentration. The results are compared with the exciton diffusion mechanism for energy transfer (hopping model) .