Patent ID: 8637854

Claim:
A stacked organic light emitting diode comprising: a first electrode; a second electrode; at least two light emitting units that are located between the first electrode and the second electrode; and an n-type doped organic layer that is located between the at least two light emitting units, wherein at least one of the at least two light emitting units comprises an n-type organic layer and a p-type organic layer that form an NP conjunction and satisfy the following energy relation equation; E pH −E nL ≦1 eV wherein E nL is a LUMO (lowest unoccupied molecular orbital) energy level of the n-type organic layer and E pH is a HOMO (highest occupied molecular orbital) energy level of the p-type organic layer, wherein the n-type organic layer that forms the NP conjunction with the p-type organic layer is in contact with the n-type doped organic layer, and wherein one of the at least two light emitting units that is in contact with the second electrode further comprises an n-type doped organic layer.