Patent ID: 7951470

Claim:
A light-emitting device comprising: a pair of substrates; and a light-emitting element between the pair of substrates, wherein the light-emitting element comprises: an anode; a mixed layer comprising a conductive inorganic compound and an aromatic amine compound over the anode; a first light emitting layer comprising a first luminescent material over the mixed layer; a carrier generating layer over the first light emitting layer; a second light emitting layer over the carrier generating layer, the second light emitting layer comprising a second luminescent material; and a cathode over the second light emitting layer, wherein the carrier generating layer comprises a first film over the first light emitting layer and a second film over the first film, wherein the first film comprises tris(8-quinolinolato)aluminum and lithium, wherein the second film comprises 4,4′-bis[N-(1-napthyl)-N-phenyl-amino]biphenyl and molybdenum oxide, and wherein the second luminescent material is a quinoxaline derivative represented by the following general formula (1): wherein R1 to R4 are hydrogen or an alkyl group having 4 carbon atoms comprising a straight-chain structure or a branch structure.