Phosphoreszenz und Verzögerte Fluoreszenz von Naphthalin in verschiedenen Mischkristallen

Abstract

Measurements of the phosphorescence and delayed fluorescence emission at temperatures between 1.6 and 50 °K are reported for the following mixed crystal systems: Naphthalene-h8 in Naphthalene-d8 and Durene; Thionaphthene, Durene and β-Methyl-Naphthalene in Naphthalene-h8 . The emitting species is either the guest molecule (trap emission) or the vicinity of the guest molecule (disturbed exciton emission of the host) . By an analysis of the temperature dependence of the intensities of delayed fluorescence and phosphorescence it can be shown that the delayed fluorescence is at least mostly due to a thermally activated triplet triplet annihilation. Triplet energy is transferred from a trap to the annihilation partner by using the exciton band of the host. Spectroscopic and thermal energy gaps between trap levels and the host exciton band are measured. In addition we report some lifetime measurements in these crystals.