Patent ID: 8076681

Claim:
A white organic electroluminescent device for emitting white light, the device comprising: a substrate; an anode placed; a hole transport layer; an emission layer having a red sub-emission layer, a green sub-emission layer, and a blue sub-emission layer; and a cathode, the anode, the hole transport layer, the emission layer and the cathode being placed on the substrate, wherein: the green sub-emission layer is placed to be in contact with the hole transport layer; the red sub-emission layer is placed to be in contact with the green sub-emission layer; the blue sub-emission layer is placed to be in contact with the red sub-emission layer; the green sub-emission layer comprises a delayed fluorescent material; the red sub-emission layer comprises a phosphorescent light emitting material; a highest occupied molecular orbital (HOMO) of the delayed fluorescent material is deeper than an HOMO of a material of the hole transport layer; and the HOMO of the delayed fluorescent material is shallower than an HOMO of the phosphorescent light emitting material.