Patent ID: 8304094

Claim:
A light-emitting element comprising: a first layer over an anode; an N layer over the first layer; a P layer over the N layer; a second layer over the P layer; and a cathode over the second layer, wherein each of the first layer and the second layer contains a third layer and a fourth layer over the third layer, wherein the third layer contains a spirofluorene derivative represented by the structure: wherein R 1 is any one of hydrogen and an alkyl group having 1 to 4 carbon atoms, each of R 2 and R 3 is any one of hydrogen and an alkyl group having 1 to 4 carbon atoms and R 2 and R 3 may be identical or different, R 4 is an aryl group having 6 to 15 carbon atoms, each of R 5 and R 6 is any one of hydrogen, an alkyl group having 1 to 4 carbon atoms, and an aryl group having 6 to 15 carbon atoms and R 5 and R 6 may be identical or different, wherein the fourth layer contains a phosphorescent compound, wherein the N layer contains an organic compound and an electron donor, and wherein the P layer contains an organic compound and an electron acceptor.