Diffusion of triplet excitons in crystalline anthracene

In this work we present an experimental study of triplet-exciton diffusion in crystalline anthracene. Triplet-exciton lifetime was determined by the time intermittency method, while the diffusion coefficients and the components of the diffusion tensor were determined by the space intermittency technique. From the comparison of the experimental data with the results of the theoretical analysis we conclude that: (a) The magnitude of the diffusion coefficient for triplet excitons [D= (2.0±0.5) ×10^-4 cm²/sec] yields a strong support for the strong scattering random-walk model for triplet-exciton migration in crystalline anthracene. (b) The diffusion tensor of triplet excitons in crystalline anthracene was found to be isotropic. (c) The isotropy of the diffusion tensor in the ab plane can be properly accounted for in terms of the calculated intermolecular electron exchange and charge-transfer interactions.