Luminescence of Benzoic Acid Polycrystals Doped with Bromated p-Terphenyls

摘要

The impurity phosphorescence that is comparable in intensity with fluorescence is found in the luminescence spectra of benzoic acid polycrystals doped with 4-bromterphenyl or 4,4'-dibromterphenyl. Theratio of efficiencies of energy transfer among singlet and triplet levels is estimated. The observed increase in the relative fluorescence intensity with increasing impurity concentration can be explained by annihilation of triplet excitons. It is shown that bromine atoms in the para-position do not affect the type of entering of bromine-containing terphenyl molecules into a cell of the benzoic acid crystal.