US Patent 7466073 Organic electroluminescent device and display apparatus

The present invention provides a phosphorescent luminescent device which has high-efficiency and a long lifetime. The organic electroluminescent device according to the present invention includes a pair of electrodes and an organic layer disposed between the pair of electrodes, wherein the organic layer has at least a light-emitting layer, and the light-emitting layer include at least a host material and dopants containing at least a first dopant and a second dopant, and wherein a triplet lowest excitation level of the first dopant is higher than a triplet lowest excitation level of the host material, and a triplet lowest excitation level of the second dopant is lower than a triplet lowest excitation level of the host material.