Diffusion Length of Triplet Excitons in Anthracene Crystals

Abstract

Recently two different experimental principles have been used to determine the diffusion length of triplet excitons and the results have differed by an order of magnitude. Experiments have now been performed using (i) singlet excitation and (ii) triplet lifetime dependence on thickness, and the results are shown to be in accord with results from other techniques. The triplet diffusion length l is shown to be 20±10 μ. Also it is found that l is slightly temperature dependent, with an apparent activation energy of approximately 10⁻² eV.