Radiative lifetime of triplet excitation recombinations mediated by spin-photon interaction in semiconductors

The radiative recombination of triplet exciton, is studied here theoretically in inorganic amorphous and organic crystalline semiconductors. A new time-dependent exciton-spin-orbit-photon interaction operator derived recently is used to calculate rates of radiative recombination of triplet excitons and the corresponding radiative lifetimes. It is illustrated that the new operator gives rise to a first order non-zero term responsible for the triplet photoluminescence. Results agree quite well with the known experimental results.