Bimolecular radiationless transitions in crystalline tetracene

Bimolecular decay of an excited singlet exciton into two triplet excitons is suggested to be an important fluorescence quenching channel in crystalline tetracene and its corresponding rate is estimated to be ∼ 4 × 1010 to 1012 sec−1. The process is tentatively proposed to account for the observed relative fluorescence efficiencies of anthracene, tetracene and pentacene.