Cross-linkable Iridium Complexes and Organic Light-Emitting Devices Using the Same

• US 20080220265A1
• Filed: 12/06/2007
• Published: 09/11/2008
• Est. Priority Date: 12/08/2006
• Status: Active Grant

• Current Assignee: Universal Display Corporation
• Original Assignee: Universal Display Corporation
• Inventors: Kwong, Raymond, Xia, Chuanjun, Brooks, Jason
• Granted Patent: US 8,119,255 B2
• Time in Patent Office: Days
• US Class Current: 428/447
• CPC Class Codes: C07F 15/0033 Iridium compounds
• 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: H10K 50/17 Carrier injection layers
• CPC Class Codes: H10K 71/311 Purifying organic semiconductor materials
• CPC Class Codes: H10K 85/324 comprising aluminium, e.g. Alq3
• CPC Class Codes: H10K 85/342 comprising iridium
• CPC Class Codes: H10K 85/622 containing four rings, e.g. pyrene
• CPC Class Codes: H10K 85/633 comprising polycyclic condensed aromatic hydrocarbons as substituents on the nitrogen atom
• CPC Class Codes: H10K 85/657 Polycyclic condensed heteroaromatic hydrocarbons
• CPC Class Codes: H10K 85/6572 comprising only nitrogen in the heteroaromatic polycondensed ring system, e.g. phenanthroline or carbazole
• CPC Class Codes: Y10S 428/917 Electroluminescent
• CPC Class Codes: Y10T 428/31663 As siloxane, silicone or silane

Abstract

Organic devices comprising an organic layer, wherein the organic layer is non-electroluminescent and comprises a cross-linked metal complex. The cross-linked metal complex may be formed by cross-linking a cross-linkable iridium complex, which comprises a set of ligands coordinated to a central iridium atom. One or more of the ligands have attached thereon, one or more polymerizable groups that are able to polymerize with other molecules to form intermolecular covalent bonds. In some cases, the organic layer may also comprise a dopant. Also provided are a method of making an organic light-emitting device, an iridium complex, and an organic-light emitting device using certain iridium complexes.

Claims

1. An organic light-emitting device, comprising:

a first electrode;

a second electrode;

a first organic layer disposed between the first electrode and the second electrode, wherein the first organic layer is non-electroluminescent, and wherein the first organic layer comprises a cross-linked metal complex; and

a second organic layer disposed between the first electrode and the second electrode, wherein the second organic layer is emissive, and wherein the second organic layer comprises an electroluminescent organic material.

2. The device of claim 1, wherein the first electrode is an anode and the first organic layer is in direct contact with the first electrode.

3. The device of claim 1, further comprising a third organic layer disposed between the first organic layer and the second organic layer.

4. The device of claim 1, wherein the cross-linked metal complex is a cross-linked organometallic complex.

5. The device of claim 4, wherein the cross-linked metal complex is a cross-linked organometallic iridium complex.

6. The device of claim 5, wherein the cross-linked metal complex is formed by cross-linking a cross-linkable iridium complex having the formula:

7. The device of claim 6, wherein the structure R₁-A-B—

R₂ is selected from the group consisting of;

8. The device of claim 6, wherein the structure A-B is

9. The device of claim 6, wherein the spacer group separates the polymerizable group from one of the pair of aromatic rings by a distance of at least 3 bonds.

10. The device of claim 9, wherein the spacer group separates the polymerizable group from one of the pair of aromatic rings by a distance of at least 5 bonds.

11. The device of claim 10, wherein the spacer group separates the polymerizable group from one of the pair of aromatic rings by a distance of at least 7 bonds.

12. The device of claim 6, wherein the spacer group includes an amine group.

13. The device of claim 6, wherein the polymerizable group is selected from the group consisting of:

vinyl, acrylate, epoxide, oxetane, trifluoroethylene, benzocyclobutene, siloxane, maleimide, cyanate ester, ethynyl, nadimide, phenylethynyl, biphenylene, phthalonitrile, and boronic acid.

14. The device of claim 6, wherein the polymerizable group is selected from the group consisting of:

vinyl, siloxane, and boronic acid.

15. The device of claim 6, wherein the variable “

a”

has a value of 2 or greater.

16. The device of claim 6, wherein the structure S—

P is selected from the group consisting of;

17. The device of claim 16, wherein the cross-linkable iridium complex is selected from the group consisting of:

18. The device of claim 6, wherein the structure S—

P is selected from the group consisting of;

19. The device of claim 18, wherein the cross-linkable iridium complex is selected from the group consisting of:

20. The device of claim 6, wherein the cross-linkable iridium complex is a polymeric molecule or a part thereof.

21. The device of claim 20, wherein the cross-linkable iridium complex has the formula:

22. The device of claim 6, wherein the cross-linkable iridium complex has the formula:

23. The device of claim 22, wherein the cross-linkable iridium complex has the formula:

24. The device of claim 23, wherein the cross-linkable iridium complex has the formula:

25. The device of claim 24, wherein the cross-linkable iridium complex has the formula:

26. The device of claim 1, wherein the first organic layer further comprises a dopant.

27. The device of claim 26, wherein the dopant is a strong electron acceptor.

28. The device of claim 26, wherein the dopant is selected from the group consisting of:

29. A method of making an organic light-emitting device, comprising:

providing a first electrode disposed on a substrate;

forming a first organic layer by solution depositing a cross-linkable metal complex over the first electrode and cross-linking the cross-linkable metal complex;

forming a second organic layer over the first electrode, wherein the second organic layer comprises an organic electroluminescent material; and

forming a second electrode disposed over the first and second organic layers.

30. The method of claim 29, wherein the first electrode is an anode and the first organic layer is in direct contact with the first electrode.

31. The method of claim 29, wherein forming the second organic layer is performed by solution deposition.

32. The method of claim 30, further comprising forming a third organic layer over the first organic layer such that the third organic layer is disposed between the first organic layer and the second organic layer;

wherein the third organic layer comprises a hole transport material.

33. The method of claim 32, wherein the hole transport material is cross-linked.

34. The method of claim 32, wherein forming the third organic layer is performed by solution deposition.

35. The method of claim 31, further comprising forming a fourth organic layer over the second organic layer;

wherein the fourth organic layer comprises an electron transport material.

36. The method of claim 31, wherein the first organic layer, after cross-linking, is insoluble in the solvent used in depositing the second organic layer.

37. The method of claim 34, wherein the first organic layer, after cross-linking, is insoluble in the solvent used in depositing the third organic layer.

38. The method of claim 29, wherein the solution used in solution depositing the cross-linkable metal complex further comprises a dopant.

39. The method of claim 38, wherein the dopant is a strong electron acceptor.

40. The method of claim 38, wherein the dopant is selected from the group consisting of:

41. The method of claim 29, wherein the cross-linkable metal complex has the formula:

42. The method of claim 41, wherein the cross-linking occurs by cross-linking of a polymerizable group on one iridium complex with a polymerizable group on another iridium complex.

43. The method of claim 41, wherein the structure R₁-A-B—

R₂ is selected from the group consisting of;

44. The method of claim 43, wherein the structure A-B is

45. The method of claim 41, wherein the spacer group separates the polymerizable group from one of the pair of aromatic rings by a distance of at least 3 bonds.

46. The method of claim 45, wherein the spacer group separates the polymerizable group from one of the pair of aromatic rings by a distance of at least 5 bonds.

47. The method of claim 46, wherein the spacer group separates the polymerizable group from one of the pair of aromatic rings by a distance of at least 7 bonds.

48. The method of claim 41, wherein the spacer group includes an amine group.

49. The method of claim 41, wherein the polymerizable group is selected from the group consisting of:

vinyl, acrylate, epoxide, oxetane, trifluoroethylene, benzocyclobutene, siloxane, maleimide, cyanate ester, ethynyl, nadimide, phenylethynyl, biphenylene, phthalonitrile, and boronic acid.

50. The method of claim 41, wherein the polymerizable group is selected from the group consisting of:

vinyl, siloxane, and boronic acid.

51. The method of claim 41, wherein the cross-linkable iridium complex is a polymeric molecule or a part thereof.

52. The method of claim 41, wherein the cross-linkable iridium complex has the formula:

53. An iridium complex having the formula:

54. The iridium complex of claim 53, wherein the spacer group S is represented by the formula:

55. The iridium complex of claim 53, wherein spacer group S includes one or more linkage units that are each independently selected from the group consisting of:

alkylene, heteroalkylene, arylene, heteroarylene, borane, ether, ester, amine, imine, amide, imide, thioether, and phosphine.

56. The iridium complex of claim 53, wherein the spacer group separates the polymerizable group from one of the pair of aromatic rings by a distance of at least 3 bonds.

57. The iridium complex of claim 56, wherein the spacer group separates the polymerizable group from one of the pair of aromatic rings by a distance of at least 5 bonds.

58. The iridium complex of claim 57, wherein the spacer group separates the polymerizable group from one of the pair of aromatic rings by a distance of at least 7 bonds.

59. An organic light-emitting device, comprising:

a first electrode;

a second electrode; and

a first organic layer comprising a covalently cross-linked matrix, wherein the cross-linked matrix comprises an iridium complex having the formula;

60. The device of claim 59, wherein the covalently cross-linked matrix is formed by cross-linking the iridium complex.

61. The device of claim 59, wherein the first electrode is an anode and the second electrode is a cathode;

and wherein the first organic layer is in direct contact with the first electrode.

62. The device of claim 61, further comprising a second organic layer disposed over the first organic layer;

wherein the second organic layer comprises an electroluminescent material.

63. The device of claim 59, wherein the spacer group S is represented by the formula:

64. The device of claim 59, wherein spacer group S includes one or more linkage units that are each independently selected from the group consisting of:

alkylene, heteroalkylene, arylene, heteroarylene, borane, ether, ester, amine, imine, amide, imide, thioether, and phosphine.

65. The device of claim 59, wherein the spacer group separates the polymerizable group from one of the pair of aromatic rings by a distance of at least 5 bonds.

66. The device of claim 65, wherein the spacer group separates the polymerizable group from one of the pair of aromatic rings by a distance of at least 5 bonds.

67. The device of claim 59, wherein the first organic layer further comprises a dopant.

68. The device of claim 67, wherein the dopant is a strong electron acceptor.

69. The device of claim 67, wherein the dopant is selected from the group consisting of:

70. A method of forming a heteroleptic metal complex, comprising:

(a) providing a solution containing a first mixture of different metal complexes;

wherein the first mixture includes a first metal complex having one or more halogen-containing groups and a second metal complex having zero or more halogen-containing groups;

wherein the number of halogen-containing groups on the first metal complex is greater than the number of halogen-containing groups on the second metal complex;

(b) forming a second mixture of different metal complexes by substituting the halogen-containing groups on the metal complexes in the first mixture with a separation enhancing functional group selected from the group consisting of;

B(OH)₂, B(OR)₂, NH₂, NHR, OH, OTf, OTs, COOH, and SiMe₃;

wherein R is a C_1-20 hydrocarbyl moiety;

wherein the second mixture includes a third metal complex having one or more of the separation enhancing functional groups and a fourth metal complex having zero or more of the separation enhancing functional groups;

wherein the number of separation enhancing functional groups on the third metal complex is greater than the number of separation enhancing functional groups on the fourth metal complex; and

(c) separating the third metal complex from the fourth metal complex.

71. The method of claim 70, wherein each of the metal complexes has one or more ligands, and wherein each of the ligands independently has the structure:

72. The method of claim 71, wherein at least one of the ligands on each of the third and fourth metal complexes does not include the separation enhancing functional group.

73. The method of claim 72, wherein the metal atom of the metal complexes is selected from the group consisting of:

iridium, platinum, and osmium.

74. The method of claim 73, wherein the first metal complex has the formula M(L₁)(L_A)₂ and the second metal complex has the formula M(L₁)₂(L_A),

wherein M is iridium;

wherein L₁ and L_A are different ligands that are coordinated to metal M;

wherein L_A includes one or more of the halogen-containing groups.

75. The method of claim 74, wherein the third metal complex has the formula M(L₁)(L_B)₂ and the fourth metal complex has the formula M(L₁)₂(L_B),

wherein L_B is a ligand that includes the separation enhancing functional group.

76. The method of claim 75, wherein the separation enhancing functional group is capable of being substituted in a coupling, deprotection, condensation, cleavage, or acylation reaction.

77. The method of claim 76, wherein the substitution reaction is catalyzed by a transition metal.

78. The method of claim 77, wherein the transition metal is palladium.

79. The method of claim 76, further comprising:

isolating the metal complex having the formula M(L₁)(L_B)₂; and

substituting the separation enhancing functional group on ligand L_B with an aryl-containing group to yield a metal complex having the formula M(L₁)(L₂)₂, wherein L₂ is a ligand that includes the aryl-containing group.

80. The method of claim 76, further comprising:

isolating the metal complex having the formula M(L₁)₂(L_B); and

substituting the separation enhancing functional group on ligand L_B with an aryl-containing group to yield a metal complex having the formula M(L₁)₂(L₂), wherein L₂ is a ligand that includes the aryl-containing group.

81. The method of claim 70, wherein the step of separating is performed by column chromatography.

82. The method of claim 70, wherein the separation enhancing functional group is a borate ester.

83. The method of claim 70, wherein the separation enhancing functional group is an amine.

84. The method of claim 70, wherein the separation enhancing functional group is a triflate.

85. The method of claim 70, wherein the separation enhancing functional group is a trimethylsilyl.

86. The method of claim 70, wherein the halogen-containing group is:

F, Cl, Br, or I.

87. The method of claim 86, wherein the halogen-containing group is:

88. A heteroleptic metal complex having one or more ligands, wherein at least one of the ligands includes a separation enhancing functional group selected from the group consisting of:

B(OH)₂, B(OR)₂, NH₂, NHR, OH, OTf, OTs, COOH, and SiMe₃;

wherein R is a C_1-20 hydrocarbyl moiety.

89. The metal complex of claim 88, wherein the ligands each independently have the structure:

90. The metal complex of claim 89, wherein at least one of the ligands does not include a separation enhancing functional group.

91. The metal complex of claim 90, wherein the metal atom of the metal complex is selected from the group consisting of:

iridium, platinum, and osmium.

92. The metal complex of claim 91, wherein the heteroleptic metal complex has the formula:

M(L₁)(L_B)₂ or M(L₁)₂(L_B);

wherein M is iridium;

wherein L₁ and L_B are different ligands that are coordinated to metal M; and

wherein L_B includes the separation enhancing functional group.

93. The metal complex of claim 92, wherein ligand L₁ is represented by the structure:

94. The metal complex of claim 88, wherein the separation enhancing functional group is a borate ester.

95. The metal complex of claim 88, wherein the separation enhancing functional group is an amine.

96. The metal complex of claim 88, wherein the separation enhancing functional group is a triflate.

97. The metal complex of claim 88, wherein the separation enhancing functional group is a trimethylsilyl.

98. The metal complex of claim 88, wherein the separation enhancing functional group is capable of being substituted in a transition metal-catalyzed coupling, deprotection, condensation, cleavage, or acylation reaction.

99. The metal complex of claim 98, wherein the transition metal catalyst is palladium.