Organic light emitting diode

1. An organic electroluminescent device comprising:

an anode;

a cathode;

a light emitting layer provided between the anode and the cathode;

a first electric charge transporting passage provided between the light emitting layer and the cathode; and

a second electric charge transporting passage provided between the light emitting layer and the anode,

wherein the first electric charge transporting passage comprises:

a first p-type organic material layer which is associated with the cathode and non-doped; and

a first n-type organic material layer provided between the first p-type organic material layer and the light emitting layer, and

wherein a thickness of the first p-type organic material layer is controlled such that a cavity length of the organic electroluminescent device is substantially an integer-fold of a wavelength of light emitted from the light emitting layer.

2. The organic electroluminescent device of claim 1 , wherein a work function of the cathode is at a HOMO energy level or less of the first p-type organic material layer.

3. The organic electroluminescent device of claim 1 , wherein a difference between the HOMO energy level of the first p-type organic material layer and a LUMO energy level of the first n-type organic material layer is 2 eV or less.

4. The organic electroluminescent device of claim 1 , further comprising:

a second n-type organic material layer provided between the first n-type organic material layer and the light emitting layer.

5. The organic electroluminescent device of claim 4 , wherein the second n-type organic material layer comprises an n-type dopant.

6. The organic electroluminescent device of claim 4 , further comprising:

a third n-type organic material layer provided between the second n-type organic material layer and the light emitting layer.

7. The organic electroluminescent device of claim 1 , wherein the cathode is in contact with the first p-type organic material layer.

8. The organic electroluminescent device of claim 1 , wherein the first n-type organic material layer and the first p-type organic material layer form an NP junction.

9. The organic electroluminescent device of claim 1 , wherein the second electric charge transporting passage comprises a second p-type organic material layer.

10. The organic electroluminescent device of claim 9 , further comprising:

a fourth n-type organic material layer provided between the second p-type organic material layer and the anode.

11. The organic electroluminescent device of claim 1 , wherein a distance from a boundary between the first p-type organic material layer and the first n-type organic material layer to the light emitting layer and a distance from the anode to the light emitting layer are controlled such that an amount of holes in the light emitting layer is balanced with that of electrons therein.

12. The organic electroluminescent device of claim 1 , wherein the distance from the boundary between the first p-type organic material layer and the first n-type organic material layer to the light emitting layer is shorter than that from the anode to the light emitting layer.

13. The organic electroluminescent device of claim 1 , wherein the distance from the boundary between the first p-type organic material layer and the first n-type organic material layer to the light emitting layer is from 100 Å to 500 Å.

14. The organic electroluminescent device of claim 1 , wherein the distance from the anode to the light emitting layer is from 500 Å to 5,000 Å.

15. The organic electroluminescent device of claim 1 , wherein a hole mobility of a hole transporting material included in the second electric charge transporting passage is faster than an electron mobility of an electron transporting material included in the first electric charge transporting passage.

16. The organic electroluminescent device of claim 1 , wherein the distance from the cathode to the light emitting layer is longer than that from the anode to the light emitting layer.

17. The organic electroluminescent device of claim 1 , wherein the first p-type organic material layer has a thickness of 5 nm or more.

18. The organic electroluminescent device of claim 1 , wherein the first n-type organic material layer comprises one or more compounds selected from a compound represented by the following Formula 2, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), fluoro-substituted 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA), cyano-substituted 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA), naphthalene tetracaboxylic dianhydride (NTCDA), fluoro-substituted naphthalene tetracaboxylic dianhydride (NTCDA), and cyano-substituted naphthalene tetracaboxylic dianhydride (NTCDA):

in Formula 2, R 1b to R 6b are each hydrogen, a halogen atom, nitrile (—CN), nitro (—NO 2 ), sulfonyl (—SO 2 R), sulfoxide (—SOR), sulfonamide (—SO 2 NR), sulfonate (—SO 3 R), trifluoromethyl (—CF 3 ), ester (—COOR), amide (—CONHR or —CONRR′), a substituted or unsubstituted straight or branched C 1 to C 12 alkoxy, a substituted or unsubstituted straight or branched C 1 to C 12 alkyl, a substituted or unsubstituted straight or branched C 2 to C 12 alkenyl, a substituted or unsubstituted aromatic or non-aromatic heterocyclic ring, a substituted or unsubstituted aryl, a substituted or unsubstituted mono- or di-aryl amine, or a substituted or unsubstituted aralkyl amine, wherein R and R′ are each a substituted or unsubstituted C 1 to C 60 alkyl, a substituted or unsubstituted aryl, or a substituted or unsubstituted 5- to 7-membered heterocyclic ring.

19. The organic electroluminescent device of claim 1 , further comprising:

a substrate provided on a surface of the cathode or the anode opposite to a surface on which the organic material layer is provided; and

a light extraction layer provided between the anode or the cathode and the substrate, or on a surface of the substrate opposite to a surface on which the anode or the cathode is provided.

20. The organic electroluminescent device of claim 1 , wherein the organic electroluminescent device is a flexible organic electroluminescent device.

21. A display comprising the organic electroluminescent device of claim 1 .

22. An illumination apparatus comprising the organic electroluminescent device of claim 1 .

23. An organic electroluminescent device comprising:

an anode;

a cathode;

a light emitting layer provided between the anode and the cathode;

a first organic material layer provided between the light emitting layer and the cathode, which transports electric charges to a HOMO energy level of the first organic material layer and is non-doped; and

a second organic material layer provided between the light emitting layer and the first organic material layer, which transports electric charges to a LUMO energy level of the second organic material layer,

wherein a thickness of the first organic material layer is controlled such that a cavity length of the organic electroluminescent device is substantially an integer-fold of a wavelength of light emitted from the light emitting layer.

24. The organic electroluminescent device of claim 23 , wherein a work function of the cathode is at a HOMO energy level or less of the first organic material layer.

25. The organic electroluminescent device of claim 23 , wherein a difference between the HOMO energy level of the first organic material layer and the LUMO energy level of the second organic material layer is 2 eV or less.

26. The organic electroluminescent device of claim 23 , further comprising:

an additional n-type organic material layer provided between the second organic material layer and the light emitting layer.

27. The organic electroluminescent device of claim 26 , wherein the additional n-type organic material layer comprises an n-type dopant.

28. The organic electroluminescent device of claim 23 , wherein the cathode is in contact with the first organic material layer.

29. The organic electroluminescent device of claim 23 , wherein the second organic material layer and the first organic material layer form an NP junction.

30. The organic electroluminescent device of claim 23 , further comprising:

an additional p-type organic material layer provided between the light emitting layer and the anode.

31. The organic electroluminescent device of claim 30 , further comprising:

an additional n-type organic material layer provided between the additional p-type organic material layer and the anode.

32. The organic electroluminescent device of claim 23 , wherein a distance from a boundary between the first organic material layer and the second organic material layer to the light emitting layer and a distance from the anode to the light emitting layer are controlled such that an amount of holes in the light emitting layer is balanced with that of electrons therein.

33. The organic electroluminescent device of claim 23 , wherein the distance from the boundary between the first organic material layer and the second organic material layer to the light emitting layer is shorter than that from the anode to the light emitting layer.

34. The organic electroluminescent device of claim 23 , wherein the distance from the cathode to the light emitting layer is longer than that from the anode to the light emitting layer.

35. The organic electroluminescent device of claim 23 , wherein the second organic material layer comprises one or more compounds selected from a compound represented by the following Formula 2, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), fluoro-substituted 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA), cyano-substituted 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA), naphthalene tetracaboxylic dianhydride (NTCDA), fluoro-substituted naphthalene tetracaboxylic dianhydride (NTCDA), and cyano-substituted naphthalene tetracaboxylic dianhydride (NTCDA):

in Formula 2, R 1b to R 6b are each hydrogen, a halogen atom, nitrile (—CN), nitro (—NO 2 ), sulfonyl (—SO 2 R), sulfoxide (—SOR), sulfonamide (—SO 2 NR), sulfonate (—SO 3 R), trifluoromethyl (—CF 3 ), ester (—COOR), amide (—CONHR or —CONRR′), a substituted or unsubstituted straight or branched C 1 to C 12 alkoxy, a substituted or unsubstituted straight or branched C 1 to C 12 alkyl, a substituted or unsubstituted straight or branched C 2 to C 12 alkenyl, a substituted or unsubstituted aromatic or non-aromatic heterocyclic ring, a substituted or unsubstituted aryl, a substituted or unsubstituted mono- or di-aryl amine, or a substituted or unsubstituted aralkyl amine, wherein R and R′ are each a substituted or unsubstituted C 1 to C 60 alkyl, a substituted or unsubstituted aryl, or a substituted or unsubstituted 5- to 7-membered heterocyclic ring.

36. An organic electroluminescent device comprising:

an anode;

a cathode;

a light emitting layer provided between the anode and the cathode; and

a buffer layer provided between the light emitting layer and the cathode,

wherein the buffer layer comprises:

a first organic material layer which is disposed closer to the cathode than the light emitting layer, transports electric charges to a HOMO energy level, and is non-doped; and

a second organic material layer which is disposed closer to the light emitting layer than the cathode and transports electric charges to a LUMO energy level,

wherein the first organic material layer is a p-type organic material layer which is in direct contact with the cathode.

37. An organic electroluminescent device comprising:

an anode;

a cathode;

a light emitting layer provided between the anode and the cathode; and

one or more organic material layers provided between the anode and the cathode,

wherein a work function of the cathode is at a HOMO energy level or less of an organic material layer which is in direct contact with the cathode,

wherein the organic material layer being in direct contact with the cathode is a first p-type organic material layer.

38. The organic electroluminescent device of claim 37 , wherein the first p-type organic material layer is non-doped.

39. The organic electroluminescent device of claim 37 , further comprising:

a first n-type organic material layer which forms an NP junction with the first p-type organic material layer.

40. The organic electroluminescent device of claim 39 , wherein a difference between the HOMO energy level of the first p-type organic material layer and a LUMO energy level of the first n-type organic material layer is 2 eV or less.

41. The organic electroluminescent device of claim 39 , further comprising:

a second n-type organic material layer provided between the first n-type organic material layer and the light emitting layer.

42. The organic electroluminescent device of claim 41 , wherein the second n-type organic material layer comprises an n-type dopant.

43. The organic electroluminescent device of claim 41 , further comprising:

a second p-type organic material layer provided between the light emitting layer and the anode.

44. The organic electroluminescent device of claim 43 , further comprising:

a third n-type organic material layer provided between the second n-type organic material layer and the light emitting layer, and

a fourth n-type organic material layer provided between the anode and the second p-type organic material layer.

45. The organic electroluminescent device of claim 44 , wherein the second p-type organic material layer and the fourth n-type organic material layer form an NP junction.