Fluorescence and phosphorescence resulting from electrochemical generationof triplet excitations

The biexcitonic annihilation of triplet products of ion recombination is in corporated in the kinetic description of electrochemiluminescence. This pro cess resulting in excitation and fluorescencence of singlets is the dominan t mechanism of the initial quenching of triplets, while their concentration is still high. Therefore, the contribution of triplets in subsequent phosp horescence is never as high as expected even at a large exergonicity of int er-ion electron transfer when the recombination to the triplet state prevai ls on recombination to the ground state of neutral products. The kinetics a nd quantum yields of fluorescence and phosphorescence are calculated by mea ns of integral encounter theory. (C) 2001 American Institute of Physics.