Diffusion of triplet excitons in anthracene crystals

Abstract

Diffusion of triplet excitons in anthracene crystals has been detected by time-dependent studies of the delayed blue fluorescence under varying spatial distribution of the exciting red light. The delayed fluorescence which results from triplet-triplet annihilation was used as a passive probe for detecting the triplets. The observed changes in the time dependence of the delayed fluorescence can be interpreted uniquely as due to triplet-exciton migration, and can be described by a diffusion equation. A diffusion constant of 2×10-4 cm2 sec-1 was obtained for triplet diffusion in the ab plane of anthracene crystals at room temperature. © 1966 The American Physical Society.