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 Q_T/Q_A = k • _cT ^p, 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) .