Organic light emitting devices having carrier transporting layers comprising metal complexes

• US 20030059647A1
• Filed: 08/23/2002
• Published: 03/27/2003
• Est. Priority Date: 08/29/2001
• Status: Active Grant

• Current Assignee: The Trustees of Princeton University (Princeton University), University of Southern California
• Original Assignee: University of Southern California
• Inventors: Forrest, Stephen R., Thompson, Mark E., Hong, Haiping, Adachi, Chihaya, Djurovich, Peter, Ren, Xiaofan
• Granted Patent: US 7,078,113 B2
• Time in Patent Office: Days
• US Class Current: 428/690
• CPC Class Codes: C09K 11/06 containing organic luminescent materials
• CPC Class Codes: C09K 2211/1029 containing one nitrogen atom as the heteroatom
• CPC Class Codes: C09K 2211/1044 containing two nitrogen atoms as heteroatoms
• CPC Class Codes: C09K 2211/185 of the platinum group, i.e. Os, Ir, Pt, Ru, Rh or Pd
• CPC Class Codes: C09K 2211/187 of the iron group metals, i.e. Fe, Co or Ni
• CPC Class Codes: C09K 2211/188 of other metals not provided for in one of the previous groups
• CPC Class Codes: H05B 33/14 characterised by the chemical or physical composition or the arrangement of the electroluminescent material , or by the simultaneous addition of the electroluminescent material in or onto the light source
• CPC Class Codes: H10K 2101/10 Triplet emission
• CPC Class Codes: H10K 2101/30 Highest occupied molecular orbital [HOMO], lowest unoccupied molecular orbital [LUMO] or Fermi energy values
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 50/14 Carrier transporting layers
• CPC Class Codes: H10K 50/18 Carrier blocking layers
• CPC Class Codes: H10K 71/30 Doping active layers, e.g. electron transporting layers
• CPC Class Codes: H10K 85/111 comprising aromatic, heteroaromatic, or aryl chains, e.g. polyaniline, polyphenylene or polyphenylene vinylene
• CPC Class Codes: H10K 85/1135 Polyethylene dioxythiophene [PEDOT]; Derivatives thereof
• CPC Class Codes: H10K 85/30 Coordination compounds
• CPC Class Codes: H10K 85/321 Metal complexes comprising a group IIIA element, e.g. Tris (8-hydroxyquinoline) gallium [Gaq3]
• CPC Class Codes: H10K 85/322 comprising boron
• CPC Class Codes: H10K 85/324 comprising aluminium, e.g. Alq3
• CPC Class Codes: H10K 85/331 Metal complexes comprising an iron-series metal, e.g. Fe, Co, Ni
• CPC Class Codes: H10K 85/342 : comprising iridium
• CPC Class Codes: H10K 85/631 : Amine compounds having at least two aryl rest on at least one amine-nitrogen atom, e.g. triphenylamine
• CPC Class Codes: H10K 85/649 : Aromatic compounds comprising a hetero atom
• CPC Class Codes: H10K 85/6565 : Oxadiazole compounds
• CPC Class Codes: Y10S 428/917 : Electroluminescent
• CPC Class Codes: Y10T 428/24942 : including components having same physical characteristic in differing degree

Abstract

Light emitting devices having charge transporting layers comprising one or more metal complexes are provided. More particularly, devices include hole transporting layers comprising at least one metal complex are disclosed. The present devices can further comprise an electron blocking layer for improved efficiency.

Claims

1. A light emitting device comprising a hole transporting layer, wherein said hole transporting layer comprises at least one metal complex.

2. The light emitting device of claim 1 wherein said hole transporting layer consists essentially of said metal complex.

3. The light emitting device of claim 1 wherein said hole transporting layer comprises an organic matrix doped with said metal complex.

4. The light emitting device of claim 1 wherein said metal complex is coordinatively saturated.

5. The light emitting device of claim 1 wherein said metal complex has a coordination number of six.

6. The light emitting device of claim 1 wherein said metal complex has a coordination number of four.

7. The light emitting device of claim 1 wherein said metal of said metal complex is a transition metal.

8. The light emitting device of claim 7 wherein said transition metal is a first row transition metal.

9. The light emitting device of claim 7 wherein said transition metal is a second or third row transition metal.

10. The light emitting device of claim 1 wherein the metal of said metal complex is Fe, Co, Ru, Pd, Os or Ir.

11. The light emitting device of claim 1 wherein the metal of said metal complex is Fe or Co.

12. The light emitting device of claim 1 wherein the metal of said metal complex is Fe.

13. The light emitting device of claim 1 wherein the metal of said metal complex is Co.

14. The light emitting device of claim 1 wherein said metal complex has one of the formulas I or II:

15. The light emitting device of claim 14 wherein said metal complex has the formula I.

16. The light emitting device of claim 15 wherein said metal complex has the formula I and wherein Ring system A and Ring system B are each monocyclic.

17. The light emitting device of claim 16 wherein said metal complex has the formula I, Ring system A is a five membered heteroaryl monocyclic ring and Ring system B is a six membered aryl or heteroaryl monocyclic ring.

18. The light emitting device of claim 17 wherein R₁₀ and R₁₁ are N, and R₁₃ is CH.

19. The light emitting device of claim 17 wherein Ring A forms pyrazole.

20. The light emitting device of claim 17 wherein Ring B forms phenyl.

21. The light emitting device of claim 14 wherein said metal is a d⁰, d¹, d²,d³,d⁴,d⁵, or d⁶ metal.

22. The light emitting device of claim 14 wherein M′

is a transition metal.

23. The light emitting device of claim 14 wherein M′

is Fe, Co, Ru, Pd, Os or Ir.

24. The light emitting device of claim 14 wherein M′

is Fe or Co.

25. The light emitting device of claim 14 wherein M′

is Co.

26. The light emitting device of claim 14 wherein M′

is Fe.

27. The light emitting device of claim 1 wherein said metal complex is Co(ppz)₃.

28. The light emitting device of claim 14 wherein said metal complex has the formula II.

29. The light emitting device of claim 14 wherein said metal atom complex has the formula II and wherein Ring systems G, K and L are each 5 or 6 member monocyclic rings.

30. The light emitting device of claim 29 wherein Ring systems G, K and L are each 5-membered heteroaryl monocyclic rings.

31. The light emitting device of claim 30 wherein R₂₁ and R₂₂ are each N.

32. The light emitting device of claim 31 wherein ring systems G, K and L each form pyrazole.

33. The light emitting device of claim 28 wherein M′

″

is a d^5/6 or d^2/3 metal.

34. The light emitting device of claim 28 wherein M′

″

is a transition metal.

35. The light emitting device of claim 28 wherein M′

″

is Fe, Co, Ru, Pd, Os or Ir.

36. The light emitting device of claim 28 wherein M′

″

is Fe or Co.

37. The light emitting device of claim 14 wherein M′

″

is Fe.

38. The light emitting device of claim 1 wherein said metal complex is FeTp′

₂.

39. The light emitting device of claim 1 further comprising an electron blocking layer.

40. The light emitting device of claim 39 wherein said electron blocking layer comprises an organic electron blocking material.

41. The light emitting device of claim 40 wherein said organic electron blocking material is selected from triarylamines or benzidenes.

42. The light emitting device of claim 39 wherein said electron blocking layer comprises a metal complex.

43. The light emitting device of claim 42 wherein said electron blocking layer consists essentially of said metal complex.

44. The light emitting device of claim 42 wherein said electron blocking layer comprises a matrix doped with said metal complex.

45. The light emitting device of claim 42 wherein said electron blocking layer has a HOMO energy level close to the HOMO energy level of said hole transporting layer.

46. The light emitting device of claim 42 wherein said electron blocking layer has a HOMO energy level higher than the HOMO energy level of said hole transporting layer.

47. The light emitting device of claim 42 wherein said metal complex of said electron blocking layer comprises a metal selected from Ga, In, Sn, or a group 8, 9, or 10 transition metal.

48. The light emitting device of claim 42 wherein said metal complex of said electron blocking layer comprises Ga.

49. The light emitting device of claim 42 wherein said metal complex of said electron blocking layer comprises a multidentate ligand.

50. The light emitting device of claim 49 wherein said multidentate ligand has a bridging atom selected from N and P.

51. The light emitting device of claim 49 wherein said multidentate ligand has a mesityl bridge moiety.

52. The light emitting device of claim 49 wherein said multidentate ligand comprises up to three mono-, bi- or tricyclic heteroaromatic moieties.

53. The light emitting device of claim 1 further comprising an electron blocking layer comprising a compound having the formula:

54. The light emitting device of claim 53 wherein

M is a trivalent metal atom;

X is CH or N;

A is N or 1,3,5-phenyl;

each R¹ and R² are H, or R¹ and R², together with the carbon atoms to which they are attached, link to form a phenyl group;

R³ is H; and

n is 1 or 2.

55. The light emitting device of claim 53 wherein M is Ga.

56. The light emitting device of claim 53 wherein said electron blocking layer comprises Ga(pma)₃.

57. The light emitting device of claim 53 wherein said metal complex of said hole transporting layer is Co(ppz)₃.

58. The light emitting device of claim 53 wherein said metal complex of said hole transporting layer is FeTp′

₂.

82. A pixel comprising the light emitting device of claim 1.

83. A pixel comprising the light emitting device claim 14.

84. A pixel comprising the light emitting device of claim 27.

85. A pixel comprising the light emitting device of claim 38.

86. A pixel comprising the light emitting device of claim 53.

88. An electronic display comprising the light emitting device of claim 1.

89. An electronic display comprising the light emitting device of claim 14.

90. An electronic display comprising the light emitting device of claim 27.

91. An electronic display comprising the light emitting device of claim 38.

92. An electronic display comprising the light emitting device of claim 53.

59. A light emitting device comprising the substructure HTL/EL or HTL/EBL/EL;

wherein each of said EL, HTL, and EBL comprise at least one metal complex.

60. A light emitting device comprising the substructure HTL/EL or HTL/EBL/EL;

wherein none of said EL, HTL, or EBL is comprised solely of organic molecules.

61. A light emitting device having a plurality of layers, said device being devoid of a layer that is composed solely of organic molecules.

62. The light emitting device of claim 61 wherein each of said layers contains at least one metal complex.

63. A light emitting device comprising a hole transporting layer, an emissive layer, and a blocking layer;

said hole transporting layer having a first HOMO energy, wherein said hole transporting layer comprises at least one metal complex;

said emissive layer comprising at least one material capable of transporting electrons, said material having a second HOMO energy; and

said blocking layer comprising a material having a HOMO energy that is between said first and second HOMO energies.

64. The device of claim 63 wherein said blocking layer resides between said hole transporting layer and said emissive layer.

65. The device of claim 63 wherein said blocking layer comprises an organic electron blocking material.

66. The light emitting device of claim 65 wherein said organic electron blocking material is selected from triarylamines or benzidenes.

67. The light emitting device of claim 63 wherein said electron blocking layer comprises a metal complex.

87. A pixel comprising the light emitting device of claim 63.

93. An electronic display comprising the light emitting device of claim 63.

68. A method of facilitating hole transport in a light emitting device, said light emitting device comprising a hole transporting layer and an emissive layer;

said hole transporting layer comprising at least one metal complex and having a first HOMO energy;

said emissive layer comprising at least one material capable of transporting electrons, said material having a second HOMO energy higher than said HOMO energy of said hole transporting layer;

said method comprising the step of placing a blocking layer between said hole transporting layer and said emissive layer, wherein said blocking layer comprises a material having a HOMO energy level that is between said first and second HOMO energies.

69. The method of claim 68 wherein said metal complex of said hole transporting layer is a complex formula I or II:

70. The method of claim 68 wherein said metal complex of said hole transporting layer is Co(ppz)₃ or FeTp′

₂.

71. The method of claim 68 wherein said blocking layer comprises at least one metal complex.

72. The method of claim 71 wherein said metal complex of said blocking layer is a compound having the formula:

73. The method of claim 71 wherein said metal complex of said blocking layer is Ga(pma)₃.

74. The method of claim 68 wherein said hole transporting layer comprises Co(ppz)₃ or FeTp′

₂, and said barrier layer comprises Ga(pma)₃.

75. A method of fabricating a light emitting device, said method comprising placing a hole transporting layer in electrical contact with an emissive layer, wherein said hole transporting layer comprises a compound of formulas I or II:

76. The method of claim 75 wherein said light emitting device further comprises an electron blocking layer.

77. The method of claim 76 wherein said electron blocking layer comprises a compound having the formula:

78. The method of claim 76 wherein said electron blocking layer comprises Ga(pma)₃.

79. The method of claim 75 wherein said compound is Co(ppz)₃ or FeTp′

₂.

80. The method of claim 75 wherein said compound is Co(ppz)₃.

81. A method of transporting holes in a hole transporting layer of a light emitting device, wherein said hole transporting layer comprises at least one metal complex, said method comprising applying a voltage across said device.