Electrophosphorescence and Improvement of Quantum Efficiency in Organic EL

The improvement of EL quantum efficency by using the lowest excited--triplet(T1) emission of organic EL devices was described. Generally speaking, electroluminescence is only resulted from the excited singlet state in organic electroluminescent devices. However, the excited triplet state in phosphorescence emission can also be used in order to im- prove the eletroluminescence efficiency. The relation of electroluminescence and phosphorescence was reviewed.