Stability OLED materials and devices

• US 9,051,344 B2
• Filed: 10/04/2005
• Issued: 06/09/2015
• Est. Priority Date: 05/06/2005
• Status: Active Grant

• Current Assignee: Universal Display Corporation
• Original Assignee: Universal Display Corporation
• Inventors: Lin, Chun, Mackenzie, Peter B., Walters, Robert W., Tsai, Jui-Yi, Brown, Cory S., Deng, Jun
• Primary Examiner(s): YAMNITZKY, MARIE ROSE
• Application Number:
  US11/241,981
• Publication Number:
  US 20060251923A1
• Time in Patent Office: 3,535 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: C07F 15/0033 Iridium compounds
• CPC Class Codes: C07F 15/0046 Ruthenium 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 2211/1059 containing three 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 2101/10 Triplet emission
• CPC Class Codes: H10K 2102/00 Constructional details relating to the organic devices covered by this subclass
• CPC Class Codes: H10K 2102/103 comprising indium oxides, e.g. ITO
• CPC Class Codes: H10K 50/10 OLEDs or polymer light-emitting diodes [PLED]
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 50/81 Anodes
• CPC Class Codes: H10K 50/82 Cathodes
• CPC Class Codes: H10K 50/826 Multilayers, e.g. opaque multilayers
• CPC Class Codes: H10K 85/342 comprising iridium
• CPC Class Codes: H10K 85/361 Polynuclear complexes, i.e. complexes comprising two or more metal centers
• CPC Class Codes: Y02E 10/549 Organic PV cells

Abstract

Organic light emitting materials and devices comprising phosphorescent metal complexes comprising ligands comprising aryl or heteroaryl groups substituted at both ortho positions are described. An organic light emitting device, comprising: an anode; a hole transport layer; an organic emissive layer comprising an emissive layer host and an emissive dopant; an electron impeding layer; an electron transport layer; and a cathode disposed, in that order, over a substrate.

Claims

1. A phosphorescent compound, wherein the phosphorescent compound is a neutral metal complex of a bidentate, tridentate, tetradentate, pentadentate, or hexadentate ligand;

wherein the ligand comprises;

a first ring directly bonded to the metal, the first ring being an imidazole;

a second ring as a substitution on the first ring and not directly bonded to the metal, the second ring being an aryl or heteroaryl ring substituted at both ortho positions by groups other than H or halide, wherein the ortho position substitutions do not form a fused ring with the second ring;

a third ring as a substitution on the first ring, the third ring being an aryl or heteroaryl ring directly bonded to the metal;

wherein the metal complex is an organometallic complex;

wherein the metal is selected from the group consisting of the non-radioactive metals with atomic numbers greater than 40; and

wherein the photoluminescent emission spectrum of the phosphorescent compound is blue-shifted compared to a comparative compound of identical structure except without the ortho position substitutions on the second ring.

2. The phosphorescent compound of claim 1, wherein both the ortho position substitutions on the second ring are aryl or heteroaryl groups.

3. The compound according to claim 2, wherein the metal is selected from the group consisting of Re, Ru, Os, Rh, Ir, Pd, Pt, and Au.

4. The compound according to claim 3, wherein the metal is selected from the group consisting of Os, Ir, and Pt.

5. The compound according to claim 4, wherein the metal is Ir.

6. The compound according to claim 2, wherein the second ring is further substituted by one or more aryl, heteroaryl, or electron withdrawing groups.

7. The compound according to claim 6, wherein the second ring is further substituted by a triphenylene group.

8. The compound according to claim 6, wherein the second ring is further substituted by a group that comprises a carbazole.

9. The compound according to claim 2, wherein the substituents at the ortho positions of the second ring are diarylaminoaryl groups.

10. The compound according to claim 2, which has a highest energy peak in a phosphorescence emission spectrum at a wavelength less than about 480 nm.

11. The compound according to claim 2, which is a homoleptic compound.

12. The compound according to claim 2, which is a heteroleptic compound.

13. The compound according to claim 2, which is a sublimable compound.

14. The compound according to claim 2, wherein the second ring is attached to a nitrogen atom of the first ring.

15. The compound according to claim 2, wherein the first and third rings collectively comprise a monoanionic bidentate ligand.

16. The compound according to claim 2, wherein the third ring is selected from the group consisting of phenyl, pyridyl, thiophenyl, furanyl, pyrrolyl, triazolyl, and pyrimidyl.

17. The compound according to claim 2, wherein the third ring is a phenyl ring substituted by one or two fluorine groups.

18. The compound according to claim 2, wherein the first and third rings are comprised within a monoanionic tridentate ligand.

19. The compound according to claim 2, wherein the first and third rings collectively comprise a neutral bidentate ligand.

20. The compound according to claim 2, wherein the metal complex comprises a bidentate, monoanionic, N,N-donor ligand.

21. The compound according to claim 2, wherein the metal complex comprises a carbene donor.

22. The compound according to claim 21, wherein the carbene donor is part of a bidentate, monoanionic ligand.

23. The compound according to claim 2, wherein the triplet energy of the arene or heteroarene corresponding to the second ring is greater than about 2.5 eV.

24. The compound according to claim 2, wherein the molecular weight of the arene or heteroarene corresponding to the second ring is greater than about 230 g/mol.

25. The compound according to claim 2, wherein the molecular weight of the arene or heteroarene corresponding to the second ring is greater than about 430 g/mol.

26. The compound according to claim 2, wherein the molecular weight of the arene or heteroarene corresponding to the second ring is greater than about 530 g/mol.

27. The compound according to claim 2, wherein the molecular weight of the arene or heteroarene corresponding to the second ring is greater than about 750 g/mol.

28. The compound according to claim 2, wherein the calculated singlet-triplet gap of the compound is less than about 0.4 eV.

29. The compound according to claim 2, wherein the calculated singlet-triplet gap of the compound is less than about 0.3 eV.

30. The compound according to claim 2, wherein the calculated singlet-triplet gap of the compound is less than about 0.2 eV.

31. The compound according to claim 2, wherein the calculated singlet-triplet gap of the compound is less than about 0.1 eV.

32. The compound according to claim 2, wherein the reduction potential of the ligand is less negative than that of the corresponding ligand with a methyl group in place of the second ring by at least about 0.1 V.

33. The compound according to claim 2, wherein the reduction potential of the ligand is less negative than that of the corresponding ligand with a methyl group in place of the second ring by at least about 0.2 V.

34. The compound according to claim 2, wherein the reduction potential of the ligand is less negative than that of the corresponding ligand with a methyl group in place of the second ring by at least about 0.3 V.

35. The compound according to claim 2, wherein the reduction potential of the ligand is less negative than that of the corresponding ligand with a methyl group in place of the second ring by at least about 0.4 V.

36. The compound according to claim 2, wherein the reduction potential of the ligand is less negative than that of the corresponding ligand with a methyl group in place of the second ring by at least about 0.5 V.

37. The compound according to claim 2, wherein delta E is less than about 0.6 eV;

wherein;

delta E=(triplet energy)−

(modified electrochemical gap);

the triplet energy is the energy of the highest energy peak in the phosphorescence emission spectrum of said metal complex, in eV; and

the modified electrochemical gap is the difference between the oxidation potential of the metal complex and the reduction potential of the neutral compound corresponding to the ligand.

38. The compound according to claim 37, wherein delta E is less than about 0.5 eV.

39. The compound according to claim 37, wherein delta E is less than about 0.4 eV.

40. The compound according to claim 37, wherein delta E is less than about 0.3 eV.

41. The compound according to claim 37, wherein delta E is less than about 0.2 eV.

42. An organic light emitting device comprising an anode, a cathode, and an emissive layer, wherein the emissive layer is located between the anode and the cathode, and the emissive layer comprises a phosphorescent compound according to claim 2, and optionally a host.

43. The compound according to claim 1, wherein the first ring is coordinated via a first nitrogen to the metal.

44. The compound according to claim 43, wherein the second ring is attached to a second nitrogen of the first ring.

45. The compound according to claim 1, wherein the metal is selected from the group consisting of Re, Ru, Os, Rh, Ir, Pd, Pt, and Au.

46. The compound according to claim 45, wherein the metal is selected from the group consisting of Os, Ir, and Pt.

47. The compound according to claim 46, wherein the metal is Ir.

48. The compound according to claim 1, wherein the second ring is further substituted by one or more aryl, heteroaryl, or electron withdrawing groups.

49. The compound according to claim 1, wherein the second ring is further substituted by a triphenylene group.

50. The compound according to claim 1, wherein the second ring is further substituted by a group that comprises a carbazole.

51. The compound according to claim 1, wherein the groups other than H or halide are alkyl groups.

52. The compound according to claim 51, wherein the groups other than H or halide are alkyl groups comprising two or more carbons.

53. The compound according to claim 1, wherein the groups other than H or halide are aryl groups.

54. The compound according to claim 1, wherein the groups other than H or halide are heteroaryl groups.

55. The compound according to claim 1, which has a highest energy peak in a phosphorescence emission spectrum at a wavelength less than about 480 nm.

56. The compound according to claim 1, which is a homoleptic compound.

57. The compound according to claim 1, which is a heteroleptic compound.

58. The compound according to claim 1, which is a sublimable compound.

59. The compound according to claim 1, wherein the first and third rings collectively comprise a monoanionic bidentate ligand.

60. The compound according to claim 59, wherein the third ring is a benzene, naphthalene, quinoline, isoquinoline, pyridine, pyrimidine, pyridazine, pyrrole, oxazole, thiazole, oxadiazole, thiadiazole, furan, or thiophene ring.

61. The compound according to claim 59, wherein the third ring is selected from the group consisting of phenyl, pyridyl, thiophenyl, furanyl, pyrrolyl, triazolyl, and pyrimidyl.

62. The compound according to claim 1, wherein the first and third rings collectively comprise a monoanionic tridentate ligand.

63. The compound according to claim 1, wherein the first and third rings collectively comprise a neutral bidentate ligand.

64. The compound according to claim 1, wherein the groups other than H or halide are selected from either (i) the group consisting of methyl, ethyl, n-propyl, isopropyl, and tert-butyl, or (ii) the following groups:

65. The compound according to claim 1, wherein the second ring is selected from 2,6-dimethylphenyl;

2,4,6-trimethylphenyl;

2,3,4,5,6-pentamethylphenyl;

2,6-dimethyl-4-phenylphenyl;

2,6-dimethyl-4-(3,5-dimethylphenyl)phenyl;

2,6-dimethyl-4-(2,6-dimethylphenyl)phenyl;

2,6-dimethyl-4-(4-pyridyl)phenyl;

2,6-dimethyl-4-(2,6-dimethyl-4-pyridyl)phenyl;

2,4-dimethyl-3-naphthyl;

2,6-dimethyl-4-cyanophenyl;

2,6-dimethyl-4-(9-carbazolyl)phenyl;

2,6-dimethyl-4-(9-phenyl-3-carbazolyl)phenyl;

2,6-dimethyl-4-(2,6-dimethyl-4-cyanophenyl)phenyl;

2,6-di-isopropylphenyl;

2,4,6-tri-isopropylphenyl;

2,6-di-isopropyl-4-phenylphenyl;

2,6-di-isopropyl-4-(3,5-dimethylphenyl)phenyl;

2,6-di-isopropyl-4-(2,6-dimethylphenyl)phenyl;

2,6-di-isopropyl-4-(4-pyridyl)phenyl;

2,6-di-isopropyl-4-(2,6-dimethyl-4-pyridyl)phenyl;

2,4-di-isopropyl-3-naphthyl;

2,6-di-isopropyl-4-cyanophenyl;

2,6-di-isopropyl-4-(9-carbazolyl)phenyl;

2,6-di-isopropyl-4-(9-phenyl-3-carbazolyl)phenyl;

2,6-di-isopropyl-4-(2,6-dimethyl-4-cyanophenyl)phenyl;

2,6-di-tert-butylphenyl;

2,6-di-tert-butyl-4-(3,5-dimethylphenyl)phenyl;

2,6-bis(trimethylsilyl)phenyl;

2,6-bis(dimethylphenylsilyl)phenyl; and

2,6-bis(trimethylsilyl)-4-(3,5-dimethylphenyl)-phenyl;

2,6-di-phenylphenyl;

2,6-di(4-isopropylphenyl)-4-isopropylphenyl;

2,6-di(4-isopropylphenyl)-4-methylphenyl;

2,6-di(4-isopropylphenyl)-4-tert-butylphenyl;

2,4,6-triphenylphenyl;

2,6-di-(4-isopropylphenyl)phenyl;

2,6-di-(3,5-dimethylphenyl)phenyl;

2,4,6-tri(4-isopropylphenyl)phenyl;

2,6-di-(4-tert-butylphenyl)phenyl;

2;

6-di-(4-fluorophenyl)phenyl;

2,6-di-(9-carbazolyl)-4-isopropylphenyl;

2,6-di-(9-phenyl-3-carbazolyl)-4-isopropylphenyl;

2,6-di-(4-methoxyphenyl)phenyl;

2,6-diphenyl-4-fluorophenyl;

2,6-di-(2-triphenylenyl)phenyl;

2,6-di-(2-triphenylenyl)-4-isopropylphenyl;

2,6-di-(2,6-dimethyl-4-pyridyl)phenyl;

2,6-di-(4-cyanophenyl)-4-isopropylphenyl;

2,6-di-2-naphthylphenyl;

2,6-di-(4-phenylphenyl)-4-isopropylphenyl;

2,6-di-(3-phenylphenyl)-4-isopropylphenyl;

2,6-di-(4-diphenylaminophenyl)phenyl;

2,6-di-(4-dimethylaminophenyl)phenyl;

2,6-di-(4-trimethylsilylphenyl)phenyl;

2,6-di-(4-triphenylsilylphenyl)phenyl;

2,6-di-(4-diphenylmethylsilylphenyl)phenyl; and

c1-c7 and c9 as follows;

66. The compound according to claim 1, wherein the first ring is selected from f1-f4 as follows:

67. The compound according to claim 1, wherein the third ring is selected from t1-t10 as follows:

68. The compound according to claim 1, wherein the ligand is selected from I1-I7, I20-I22, I41-I46 as follows:

69. The compound according to claim 1, wherein the metal complex is selected from the following:

70. The compound according to claim 1, wherein the metal complex comprises a bidentate, monoanionic, N,N-donor ligand.

71. The compound according to claim 1, wherein the metal complex comprises a carbene donor.

72. The compound according to claim 71, wherein the carbene donor is part of a bidentate, monoanionic ligand.

73. The compound according to claim 1, wherein the triplet energy of the arene or heteroarene corresponding to the second ring is greater than about 2.5 eV.

74. The compound according to claim 1, wherein the molecular weight of the arene or heteroarene corresponding to the second ring is greater than about 230 g/mol.

75. The compound according to claim 74, wherein the molecular weight of the arene or heteroarene corresponding to the second ring is greater than about 430 g/mol.

76. The compound according to claim 74, wherein the molecular weight of the arene or heteroarene corresponding to the second ring is greater than about 530 g/mol.

77. The compound according to claim 74, wherein the molecular weight of the arene or heteroarene corresponding to the second ring is greater than about 750 g/mol.

78. The compound according to claim 1, wherein the calculated singlet-triplet gap of the compound is less than about 0.4 eV.

79. The compound according to claim 78, wherein the calculated singlet-triplet gap of the compound is less than about 0.3 eV.

80. The compound according to claim 78, wherein the calculated singlet-triplet gap of the compound is less than about 0.2 eV.

81. The compound according to claim 78, wherein the calculated singlet-triplet gap of the compound is less than about 0.1 eV.

82. The compound according to claim 1, wherein the reduction potential of the ligand is less negative than that of the corresponding ligand with a methyl group in place of the second ring by at least about 0.1 V.

83. The compound according to claim 82, wherein the reduction potential of the ligand is less negative than that of the corresponding ligand with a methyl group in place of the second ring by at least about 0.2 V.

84. The compound according to claim 82, wherein the reduction potential of the ligand is less negative than that of the corresponding ligand with a methyl group in place of the second ring by at least about 0.3 V.

85. The compound according to claim 82, wherein the reduction potential of the ligand is less negative than that of the corresponding ligand with a methyl group in place of the second ring by at least about 0.4 V.

86. The compound according to claim 82, wherein the reduction potential of the ligand is less negative than that of the corresponding ligand with a methyl group in place of the second ring by at least about 0.5 V.

87. The compound according to claim 1, wherein delta E is less than about 0.6 eV;

wherein;

delta E=(triplet energy)−

(modified electrochemical gap);

the triplet energy is the energy of the highest energy peak in the phosphorescence emission spectrum of said metal complex, in eV; and

the modified electrochemical gap is the difference between the oxidation potential of the metal complex and the reduction potential of the neutral compound corresponding to the ligand.

88. The compound according to claim 87, wherein delta E is less than about 0.5 eV.

89. The compound according to claim 87, wherein delta E is less than about 0.4 eV.

90. The compound according to claim 87, wherein delta E is less than about 0.3 eV.

91. The compound according to claim 87, wherein delta E is less than about 0.2 eV.

92. An organic light emitting device comprising an anode, a cathode, and an emissive layer, wherein the emissive layer is located between the anode and the cathode, and the emissive layer comprises a phosphorescent compound according to claim 1, and optionally a host.

93. The compound of claim 1, wherein the emission spectrum of the compound has a peak wavelength at less than 500 nm.