Triplet exciton fusion at dislocations in anthracene

The fusion reaction of triplet excitons trapped at edge dislocations (001)[010] was studied in anthracene crystals by observing delayed fluorescence. The fusion rate obtained by kinetic analysis which includes the exciton-trapping effect is about unity measured in cm³ s ^-1, which is much greater than the fusion rate of free excitons (≅4×10^-12 cm³ s^-1), and also greater than an estimation based on the diffusion transport of trapped excitons along the dislocation line. The fusion mechanism of a pair of trapped excitons must be dominated by some long-range interaction.