Light-emitting element, light-emitting device, electronic device, and lighting device comprising a phthalocyanine-based material
View Patent ↗A light-emitting element that emits light with high luminance and can be driven at low voltage. The light-emitting element includes n (n is a natural number greater than or equal to 2) EL layers between an anode and a cathode, and includes a first layer, a second layer, and a third layer between an m-th (m is a natural number, 1≦m≦n−1) EL layer from the anode and an (m+1)th EL layer. The first layer functions as a charge-generation region, has hole-transport properties, and contains an acceptor substance. The third layer has electron-transport properties and contains an alkali metal or the like. The second layer is formed of a phthalocyanine-based material and is provided between the first layer and the third layer, whereby an injection barrier at the time of injecting electrons generated in the first layer into the m-th EL layer through the third layer can be lowered.
1. A light-emitting element comprising:
n EL layers between an anode and a cathode, n being a natural number greater than or equal to 2; and
a first layer, a second layer, and a third layer between an m-th EL layer from the anode and an (m+1)th EL layer, m being a natural number greater than or equal to 1 and lesser than or equal to (n−1),
wherein the first layer is provided between the (m+1)th EL layer and the second layer, is in contact with the (m+1)th EL layer and the second layer, contains an organic compound and an oxide of a transition metal or an oxide of a metal belonging to any one of Groups 4 to 8 of the periodic table,
wherein the second layer is provided between the first layer and the third layer, is in contact with the first layer and the third layer, is formed of a phthalocyanine-based material, and contains an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal compound, an alkaline earth metal compound, or a rare earth metal compound,
wherein the third layer is provided between the second layer and the m-th EL layer, is in contact with the second layer and the m-th EL layer contains an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal compound, an alkaline earth metal compound, or a rare earth metal compound, and
wherein the phthalocyanine-based material is any of the materials shown by the following structural formulae
2. A light-emitting device comprising the light-emitting element according to claim 1 .
3. An electronic device comprising the light-emitting device according to claim 2 .
4. A lighting device comprising the light-emitting device according to claim 2 .
5. The light-emitting element according to claim 1 ,
wherein a LUMO level of the second layer is greater than or equal to —5.0 eV less than or equal to —3.0 eV.
6. The light-emitting element according to claim 1 ,
wherein the organic compound does not contain an amine skeleton.
7. A light-emitting element comprising:
n EL layers between an anode and a cathode, n being a natural number greater than or equal to 2; and
a first layer, a second layer, and a third layer between an m-th EL layer from the anode and an (m+1)th EL layer, m being a natural number greater than or equal to 1 and lesser than or equal to (n−1),
wherein the first layer is provided between the (m +1)th EL layer and the second layer, is in contact with the (m+1)th EL layer and the second layer, and contains an organic compound and an acceptor substance,
wherein the second layer is provided between the first layer and the third layer, is in contact with the first layer and the third layer, and is formed of a phthalocyanine-based material,
wherein the second layer further comprises an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal compound, an alkaline earth metal compound, or a rare earth metal compound,
wherein the third layer is provided between the second layer and the m-th EL layer, is in contact with the second layer and the m-th EL layer and contains an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal compound, an alkaline earth metal compound, or a rare earth metal compound, and
wherein the phthalocyanine-based material is any of the materials shown by the following structural formulae
8. The light-emitting element according to claim 7 ,
wherein the first layer functions as a charge generation layer and has hole-transport properties; and
wherein the third layer has electron-transport properties.
9. The light-emitting element according to claim 7 ,
wherein the third layer further comprises an electron-transport substance, and
wherein, in the third layer, a mass ratio of the alkali metal, the alkaline earth metal, the rare earth metal, the alkali metal compound, the alkaline earth metal compound, or the rare earth metal compound to the electron-transport substance is from 0.001:1 to 0.1:1.
10. The light-emitting element according to claim 7 ,
wherein the third layer further comprises an electron-transport substance, and
wherein a layer containing the electron-transport substance and a layer containing the alkali metal, the alkaline earth metal, the rare earth metal, the alkali metal compound, the alkaline earth metal compound, or the rare earth metal compound are stacked.
11. The light-emitting element according to claim 7 ,
wherein the acceptor substance is an oxide of a transition metal or an oxide of a metal belonging to any one of Groups 4 to 8 of the periodic table.
12. The light-emitting element according to claim 7 ,
wherein the acceptor substance is molybdenum oxide.
13. The light-emitting element according to claim 7 ,
wherein the first layer further comprises a hole-transport substance, and
wherein a layer containing the hole-transport substance and a layer containing the acceptor substance are stacked.
14. The light-emitting element according to claim 7 ,
wherein, in the second layer, a mass ratio of the alkali metal, the alkaline earth metal, the rare earth metal, the alkali metal compound, the alkaline earth metal compound, or the rare earth metal compound to the phthalocyanine-based material is from 0.001:1 to 0.1:1.
15. A light-emitting device comprising the light-emitting element according to claim 7 .
16. An electronic device comprising the light-emitting device according to claim 15 .
17. A lighting device comprising the light-emitting device according to claim 15 .
18. The light-emitting element according to claim 7 ,
wherein a LUMO level of the second layer phthalocyanine-based material is greater than or equal to —5.0 eV less than or equal to —3.0 eV.
19. The light-emitting element according to claim 7 ,
wherein a LUMO level of the second layer is located between a LUMO level of the acceptor substance in the first layer and a LUMO level of the m-th EL layer.
20. The light-emitting element according to claim 7 ,
wherein the organic compound does not contain an amine skeleton.
21. A light-emitting element comprising:
n EL layers between an anode and a cathode, n being a natural number greater than or equal to 2; and
a first layer, a second layer, and a third layer between an m-th EL layer from the anode and an (m+1)th EL layer, m being a natural number greater than or equal to 1 and lesser than or equal to (n−1),
wherein the first layer is provided between the (m+1)th EL layer and the second layer, is in contact with the (m+1)th EL layer and the second layer, contains an organic compound and an acceptor substance,
wherein the second layer is provided between the first layer and the third layer, is in contact with the first layer and the third layer, and is formed of a phthalocyanine-based material having a phenoxy group,
wherein the second layer further comprises an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal compound, an alkaline earth metal compound, or a rare earth metal compound,
wherein the third layer is provided between the second layer and the m-th EL layer, is in contact with the second layer and the m-th EL layer, and contains an alkali metal, an alkaline earth metal, a rare earth metal, an alkali metal compound, an alkaline earth metal compound, or a rare earth metal compound, and
wherein the phthalocyanine-based material is the material shown by the following structural formula
22. The light-emitting element according to claim 21 ,
wherein the first layer functions as a charge generation layer and has hole-transport properties; and
wherein the third layer has electron-transport properties.
23. The light-emitting element according to claim 21 ,
wherein the third layer further comprises an electron-transport substance, and
wherein, in the third layer, a mass ratio of the alkali metal, the alkaline earth metal, the rare earth metal, the alkali metal compound, the alkaline earth metal compound, or the rare earth metal compound to the electron-transport substance is from 0.001:1 to 0.1:1.
24. The light-emitting element according to claim 21 ,
wherein the third layer further comprises an electron-transport substance, and
wherein a layer containing the electron-transport substance and a layer containing the alkali metal, the alkaline earth metal, the rare earth metal, the alkali metal compound, the alkaline earth metal compound, or the rare earth metal compound are stacked.
25. The light-emitting element according to claim 21 ,
wherein the acceptor substance is an oxide of a transition metal or an oxide of a metal belonging to any one of Groups 4 to 8 of the periodic table.
26. The light-emitting element according to claim 21 ,
wherein the acceptor substance is molybdenum oxide.
27. The light-emitting element according to claim 21 ,
wherein the first layer further comprises a hole-transport substance, and
wherein a layer containing the hole-transport substance and a layer containing the acceptor substance are stacked.
28. The light-emitting element according to claim 21 ,
wherein, in the second layer, a mass ratio of the alkali metal, the alkaline earth metal, the rare earth metal, the alkali metal compound, the alkaline earth metal compound, or the rare earth metal compound to the phthalocyanine-based material is from 0.001:1 to 0.1:1.
29. A light-emitting device comprising the light-emitting element according to claim 21 .
30. An electronic device comprising the light-emitting device according to claim 29 .
31. A lighting device comprising the light-emitting device according to claim 29 .
32. The light-emitting element according to claim 21 ,
wherein a LUMO level of the second layer is greater than or equal to —5.0 eV less than or equal to —3.0 eV.
33. The light-emitting element according to claim 21 ,
wherein the organic compound does not contain an amine skeleton.