Structural Imperfections as Triplet Exciton Traps in Anthracene Crystals

Abstract

Structural imperfections were generated in anthracene single crystals at 93 K by plastic bending and thermal stress. The number of stages in the triplet exciton traps and the anneal characteristics of the defects were measured at 93-423 K and then analyzed quantitatively. The depth of the triplet exciton trap (0.37, 0.26 eV) and the activation energies for defect-recovery (1.34, 1.09 eV) were obtained for ((001) [O1O] and (001) [1OO]) edge dislocations, introduced by bending along the n and b crystal axis, respectively. Each dislocation is accompanied by one or two shallower traps. Thermal defects consisted of all traps observed in the mechanically-deformed samples plus two other traps annealed at below room temperature.

Keywords:

• anthracene
• crystal defects
• triplet excitons
• trapping
• annealing
• activation energy