Electroluminescent devices based on polymer/phosphorescent complexes have become a novel and attractive area of research in recent years. In this review

characteristics of both polymer matrices and phosphorescent dopants

the electrophosphorescent mechanism and device structure have been introduced. The advantage of phosphorescent materials is that they can utilize both singlet and triplet exciton states which can reach 100% internal quantum efficiency theoretically. The system requires polymer matrices satisfy energy matching between polymer host and phosphorescent dopant and have good carrier mobility. All the phosphorescent materials can be used as dopants for EL devices

which is a significant advantage of polymer host over small molecule host. Grafting and incorporating phosphorescent polymers can be used as a novel kind of luminescence materials with less self-quenching and more efficient energy transfer. Electroluminescence of these devices is from both Föster energy transfer and exciton directly recombination on the dopant

so it is necessary to be in view of the interaction and self-quenching of the excitons while designing the suitable structures of devices.