Patent ID: 7151339
Filing Date: 2006-12-19
Classification: H01L

Abstract:
1. An organic light emitting device comprising an emissive layer disposed between and electrically connected to an anode and a cathode, wherein the emissive layer comprises a host material and a phosphorescent emissive material, and wherein the concentration of the phosphorescent emissive material in the host material on the anode-side of the emissive layer is about 1% to about 50%, the concentration of the phosphorescent emissive material in the host material on the cathode-side of the emissive layer is about 0.5% to about 20%, and the difference between the concentrations of the phosphorescent emissive material in the host material on the anode-side of the emissive layer and the cathode side of the emissive layer is at least about 0.5%.