Triplet Exciton Decay Processes in Crystalline Tetracene

The decay of triplet excitons in crystalline tetracene is investigated. The monomolecular decay is characterised by a rate constant βt ≈ 5 × 103 s−1 and the bimolecular annihilation of triplet excitons is characterised by a rate constant γtt ≈ 2 × 10−11 cm3 s−1. The interaction between mobile triplet excitons and trapped holes is characterised by a rate constant γth ≈ 1 × 10−11 cm3 s−1. These values differ by two orders of magnitude from previous estimates. Some possible reasons for this are discussed.