Triplet Exciton Trapping by Dislocations in Anthracene Crystals

Abstract

Trapping of triplet excitons at dislocations, produced in anthracene crystals by plastic bending, was investigated by means of the temperature and the radius-of-curvature dependence of the triplet decay rate. As a result of the kinetic analysis, the trapping depth of 0.3 eV was obtained. The trapping rate constant was found to be dependent on the square root of the curvature, the dependence being related to the diffusion of triplet excitons in the ab plane and to the distance between dislocations. This phenomenon was re-analyzed by applying a one dimensional random-walk model.