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Highly transparent organic light emitting device employing a non-metallic cathode

Imported: 23 Feb '17 | Published: 22 Oct '02

Gautam Parthasarathy, Paul Burrows, Stephen R. Forrest

USPTO - Utility Patents

Abstract

Organic light emitting devices are disclosed which include a heterostructure for producing electroluminescence wherein the heterostructure includes a non-metallic cathode. As a representative embodiment of the present invention, the heterostructure for producing electroluminescence includes in order,

a non-metallic cathode layer (

1),

an electron injecting interface layer (

6),

an electron transporting layer (

2),

a hole transporting layer (

3),

and an anode layer (

4);

wherein the non-metallic cathode layer (

1) includes an indium-tin oxide layer in contact with a copper phthalocyanine layer which functions as the electron injecting interface layer (

6).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a standard prior art device having a metallic Mg:Ag cathode layer

1, an electron transporting layer

2, a hole transporting layer

3, an anode layer

4 and a substrate

5.

FIG. 2

a shows an OLED having a non-metallic cathode

1, an electron injecting interface layer

6, an electron transporting layer

2, a hole transporting layer

3, an anode layer

4 and a substrate

5.

FIG. 2

b shows an OLED having a non-metallic layer

1, an electron injecting interface layer

6, an intermediate electron transporting layer

7, an electron transporting layer

2, a hole transporting layer

3, an anode layer

4 and a substrate

5.

FIG. 3 shows the light output vs. current of an OLED as shown in FIG. 2

a having an ITO cathode layer and a CuPc electron injecting interface layer. The lowest set of values in this figure was obtained at 180 hours.

FIG. 4 shows the light output vs. current of a standard prior art TOLED device having an Mg:Ag cathode layer. The lower set of values in this figure was measured at 180 hours.

FIG. 5 shows the I-V curves for a ZnPc (“zns23”) electron injecting interface layer and a CuPc (cus20”) electron injecting interface layer.

FIG. 6 shows the light output vs. current for a ZnPc (“zns23li”) electron injecting interface layer as compared with a CuPc (“cu20li”), electron injecting interface layer where the efficiency of the CuPc device was 0.23% and the ZnPc device was 0.15%.

FIG. 7 shows the transmission (T), reflection (R) and absorption (A), as a function of wavelength (nm), of an OLED having an ITO cathode and CuPc electron injecting interface layer.

FIG. 8 shows the I-V characteristics of a standard prior art OLED having a metallic Mg:Ag cathode layer with the higher set of values at 0 hours and the lower set of values at 180 hours.

FIG. 9 shows the I-V characteristics of an OLED having an ITO cathode and a CuPc electron injecting interface layer with the higher set of values at 0 hours and the lower set of values at 60 and 180 hours.

FIG. 10 shows the light output vs. current for devices having CuPc injection layer thicknesses from about 30 Å up to about 120 Å. These devices show a quantum efficiency of about 0.1%.

FIG. 11 shows the I-V characteristics of the devices of FIG.

10.

Claims

1. An organic light emitting device comprising a heterostructure for producing electroluminescence wherein the heterostructure includes a non-metallic cathode comprising a transparent semi-conducting inorganic material in direct contact with a conductive organic layer, wherein said conductive organic layer comprises a phthalocyanine.

2. The organic light emitting device of claim 1 wherein said transparent semi-conducting inorganic material comprises indium tin oxide.

3. The organic light emitting device of claim 2 wherein the heterostructure for producing electroluminescence is further comprised of, in order:

4. The organic light emitting device of claim 3 wherein said second electron transporting layer comprises 4,4′-di(N-carbazolo)diphenyl.

5. The organic light emitting device of claim 1, wherein said phthalocyanine comprises copper phthalocyanine.

6. The organic light emitting device of claim 1 wherein said phthalocyanine comprises zinc phthalocyanine.

7. An organic light emitting device comprising a heterostructure for producing electroluminescence wherein the heterostructure includes a non-metallic cathode comprising a transparent semi-conducting inorganic material in direct contact with a conductive organic layer, wherein the heterostructure for producing electroluminescence is further comprised of, in order,

8. The organic light emitting device of claim 7 wherein said non-metallic cathode is comprised of indium tin oxide.

9. The organic light emitting device of claim 7 wherein said anode layer is in contact with a substrate.

10. The organic light emitting device of claim 9 wherein said substrate is transparent.

11. The organic light emitting device of claim 7 wherein said non-metallic cathode is in contact with a substrate.

12. The organic light emitting device of claim 11 wherein said substrate is transparent.

13. A display incorporating the organic light emitting device of claim 7.

14. A heads-up display incorporating the organic light emitting device of claim 7.

15. A flat panel display incorporating the organic light emitting device of claim 7.

16. A vehicle incorporating the organic light emitting device of claim 7.

17. A computer incorporating the organic light emitting device of claim 7.

18. A television incorporating the organic light emitting device of claim 7.

19. A printer incorporating the organic light emitting device of claim 7.

20. A wall, theater or stadium screen incorporating the organic light emitting device of claim 7.

21. A billboard or a sign incorporating the organic light emitting device of claim 7.

22. An organic light emitting device comprising a heterostructure for producing electroluminescence wherein the heterostructure includes a non-metallic cathode comprising a transparent semi-conducting inorganic material in direct contact with a conductive organic layer, wherein the heterostructure for producing electroluminescence is further comprised of, in order,

23. The organic light emitting device of claim 22 wherein said second electron transporting layer is comprised of 4,4′-di(N-carbazolo)diphenyl.

24. The organic light emitting device of claim 22 wherein said electron injecting interface layer is comprised of 4,4′-di(N-carbazolo)diphenyl.

25. An organic light emitting device comprising a heterostructure for producing electroluminescence wherein the heterostructure includes a non-metallic cathode comprising a transparent semi-conducting inorganic material in direct contact with a conductive organic layer, wherein the heterostructure for producing electroluminescence is further comprised of, in order,

26. The organic light emitting device of claim 25 wherein said hole injection enhancement layer is comprised of copper phthalocyanine.

27. A stacked organic light emitting device comprising:

wherein said transparent semi-conducting inorganic material functions as the anode layer in said second heterostructure.

28. The stacked organic light emitting device of claim 27, wherein said transparent semi-conducting inorganic material comprises indium tin oxide.

29. An organic light emitting device comprising, in order,

wherein said non-metallic cathode layer comprises a transparent semi-conducting inorganic material and said non-metallic cathode layer is in direct contact with said conductive organic layer.

30. The organic light emitting device of claim 29 wherein said transparent semi-conducting inorganic material comprises indium tin oxide.

31. The organic light emitting device of claim 30 wherein said substrate is transparent.

32. The organic light emitting device of claim 30 wherein said substrate is flexible.

33. The organic light emitting device of claim 30 wherein said conductive organic layer is an electron transporting material having a carrier mobility of at least 10

−6 cm

2/Vsec.

34. The organic light emitting device of claim 30 wherein an emissive layer is present between said electron transporting layer and said hole transporting layer.

35. The organic light emitting device of claim 30 wherein:

wherein the difference between the first ionization potential and the first HOMO/LUMO gap energy is not more than about 0.5 eV greater than the difference between the second ionization potential and the second HOMO/LUMO gap energy.

36. The organic light emitting device of claim 35 wherein:

37. The organic light emitting device of claim 30 wherein said hole transporting layer comprises a hole transporting material selected from the group consisting of N,N′-diphenyl-N,N′-bis(3-methylpheny)1-1′biphenyl-4,4′diamine, 4,4′-bis[N-(1-naphthyl)-N-phenyl-amino]biphenyl and 4,4′-bis[N-(2-naphthyl)-N-phenyl-amino]biphenyl.

38. The organic light emitting device of claim 30 wherein said first electron transporting layer comprises tris-(8-hydroxyquinoline)-aluminum.

39. The organic light emitting device of claim 29 wherein a second electron transporting layer is present between said first electron transporting layer and said conductive organic layer.

40. The organic light emitting device of claim 39 wherein said second electron transporting layer comprises 4,4′-di(N-carbazolo)diphenyl.

41. The organic light emitting device of claim 29 wherein said conductive organic layer comprises a phthalocyanine.

42. The organic light emitting device of claim 41 wherein said phthalocyanine comprises copper phthalocyanine.

43. The organic light emitting device of claim 41 wherein said phthalocyanine comprises zinc phthalocyanine.

44. An organic light emitting device comprising, in order,

wherein said non-metallic cathode layer comprises a transparent semi-conducting inorganic material, and said non-metallic cathode layer is in direct contact with said conductive organic layer.

45. The organic light emitting device of claim 44 wherein said transparent semi-conducting inorganic material comprises indium tin oxide.

46. The organic light emitting device of claim 45 wherein said substrate is transparent.

47. The organic light emitting device of claim 45 wherein said substrate is flexible.

48. The organic light emitting device of claim 45 wherein said conductive organic layer is an electron transporting material having a carrier mobility of at least 10

−6 cm

2/Vsec.

49. The organic light emitting device of claim 45 wherein said conductive organic layer is an emissive layer;

50. The organic light emitting device of claim 45 wherein said hole transporting layer is an emissive layer;

51. The organic light emitting device of claim 45 wherein said hole transporting layer comprises a hole transporting material selected from the group consisting of N,N′-diphenyl-N,N′-bis(3-methylpheny)1-1′biphenyl-4,4′diamine, 4,4′-bis[N-(1-naphthyl)-N-phenyl-amino]biphenyl and 4,4′-bis[N-(2-naphthyl)-N-phenyl-amino]biphenyl.

52. The organic light emitting device of claim 45 wherein said first electron transporting layer comprises tris-(8-hydroxyquinoline)-aluminum.

53. The organic light emitting device of claim 45 wherein said conductive organic layer comprises a phthalocyanine.

54. The organic light emitting device of claim 53 wherein said phthalocyanine comprises copper phthalocyanine.

55. The organic light emitting device of claim 53 wherein said phthalocyanine comprises zinc phthalocyanine.

56. An organic light emitting device comprising, in order,

wherein said non-metallic cathode layer comprises a transparent semi-conducting inorganic material.

57. The organic light emitting device of claim 56 wherein said transparent semi-conducting inorganic material comprises indium tin oxide.

58. The organic light emitting device of claim 57 wherein said substrate is transparent.

59. The organic light emitting device of claim 57 wherein said substrate is flexible.

60. The organic light emitting device of claim 57 wherein said conductive organic layer is an electron transporting material having a carrier mobility of at least 10

−6 cm

2/Vsec.

61. The organic light emitting device of claim 57 wherein:

wherein the difference between the first ionization potential and the first HOMO/LUMO gap energy is not more than about 0.5 eV greater than the difference between the second ionization potential and the second HOMO/LUMO gap energy.

62. The organic light emitting device of claim 61 wherein:

63. The organic light emitting device of claim 57 wherein said hole transporting layer comprises a hole transporting material selected from the group consisting of N,N′-diphenyl-N,N′-bis(3-methylpheny)1-1′biphenyl-4,4′diamine, 4,4′-bis[N-(1-naphthyl)-N-phenyl-amino]biphenyl and 4,4′-bis[N-(2-naphthyl)-N-phenyl-amino]biphenyl.

64. The organic light emitting device of claim 57 wherein said first electron transporting layer comprises tris-(8-hydroxyquinoline)-aluminum.

65. The organic light emitting device of claim 57 wherein said conductive organic layer comprises a phthalocyanine.

66. The organic light emitting device of claim 65 wherein said phthalocyanine comprises copper phthalocyanine.

67. The organic light emitting device of claim 65 wherein said phthalocyanine comprises zinc phthalocyanine.

68. An organic light emitting device comprised of, in order:

wherein said non-metallic cathode layer comprises a transparent semi-conducting inorganic material.

69. An organic light emitting device comprising, in order,

wherein said non-metallic cathode layer comprises a transparent semi-conducting inorganic material.

70. The organic light emitting device of claim 69 wherein said transparent semi-conducting inorganic material comprises indium tin oxide.

71. The organic light emitting device of claim 70 wherein said substrate is transparent.

72. The organic light emitting device of claim 70 wherein said substrate is flexible.

73. The organic light emitting device of claim 70 wherein said conductive organic layer is an electron transporting material having a carrier mobility of at least 10

−6 cm

2/Vsec.

74. The organic light emitting device of claim 70 wherein said conductive organic layer is an emissive layer;

75. The organic light emitting device of claim 70 wherein said hole transporting layer is an emissive layer;

76. The organic light emitting device of claim 70 wherein said hole transporting layer comprises a hole transporting material selected from the group consisting of N,N′-diphenyl-N,N′-bis(3-methylpheny)1-1′biphenyl-4,4′diamine, 4,4′-bis[N-(1-naphthyl)-N-phenyl-amino]biphenyl and 4,4′-bis[N-(2-naphthyl)-N-phenyl-amino]biphenyl.

77. The organic light emitting device of claim 70 wherein said first electron transporting layer comprises tris-(8-hydroxyquinoline)-aluminum.

78. The organic light emitting device of claim 70 wherein said conductive organic layer comprises a phthalocyanine.

79. The organic light emitting device of claim 78 wherein said phthalocyanine comprises copper phthalocyanine.

80. The organic light emitting device of claim 78 wherein said phthalocyanine comprises zinc phthalocyanine.

81. A device comprising an organic light emitting device including a transparent, non-metallic, semi-conductive inorganic material comprising indium tin oxide in direct contact with a conductive organic layer, wherein said semi-conductive inorganic material functions as a cathode in said organic light emitting device wherein said conductive organic layer comprises a phthalocyanine.

82. The organic light emitting device of claim 81 wherein said phthalocyanine comprises copper phthalocyanine.

83. The organic light emitting device of claim 81 wherein said phthalocyanine comprises zinc phthalocyanine.

84. The organic light emitting device of claim 81 wherein said conductive organic layer is an electron transporting material having a carrier mobility of at least 10

−6 cm

2/Vsec.

85. A stacked organic light emitting device comprising:

86. The stacked organic light emitting device of claim 85 wherein said conductive organic layer comprises a phthalocyanine.

87. The stacked organic light emitting device of claim 86 wherein said phthalocyanine comprises copper phthalocyanine.

88. The stacked organic light emitting device of claim 86 wherein said phthalocyanine comprises zinc phthalocyanine.

89. The stacked organic light emitting device of claim 85 wherein said conductive organic layer is an electron transporting material having a carrier mobility of at least 10

−6 cm

2/Vsec.