Patent ID: 8659008

Claim:
A light emitting device comprising: a light emitting element over a substrate, the light emitting element comprising: a layer including a light emitting substance between a pair of electrodes, wherein the layer including the light emitting substance includes at least a first layer including a first composite material and a second layer including a second composite material, wherein the first layer including the first composite material is provided to be in contact with one of the pair of electrodes serving as an anode, and the second layer including the second composite material is provided to be in contact with the other electrode of the pair of electrodes serving as a cathode, wherein the first composite material and the second composite material includes a metal oxide and an organic compound having an oxidation peak potential with respect to an Ag/Ag + electrode in dimethylformamide (DMF) at room temperature within the range of 0 V or more and 1.5 V or less (vs. Ag/Ag + ), and wherein the metal oxide is one or more selected from the group consisting of niobium oxide, tantalum oxide, and manganese oxide.