Luminescence of Benzoic Acid Polycrystals Doped with Bromated Diphenyls

摘要

The intense phosphorescence of 4-bromdiphenyl and 4,4'-dibromdiphenyl impurities in benzoic acid polycrystals is found. The phosphorescence is caused by triplet–triplet energy transfer from a matrix to the impurity and by a decrease in the nonradiative degradation of energy in bromated diphenyl molecules. The heavy bromine atoms contained in diphenyl molecules change amplitudes of molecular vibrations, resulting in a decrease in the rate constant of degradation of the triplet state. The emitting impurity molecules are located on the crystal surface.