Microcavity oled device

• US 20050037232A1
• Filed: 08/14/2003
• Published: 02/17/2005
• Est. Priority Date: 08/14/2003
• Status: Active Grant

• Current Assignee: Global OLED Technology LLC (LG Display Co., Ltd.)
• Original Assignee: Eastman Kodak Company
• Inventors: Tyan, Yuan-Sheng, Shore, Joel D., Farruggia, Giuseppe, Van Slyke, Steven A., Deaton, Joseph C.
• Granted Patent: US 6,917,159 B2
• Time in Patent Office: Days
• US Class Current: 428/690
• CPC Class Codes: H10K 50/852 comprising a resonant cavity structure, e.g. Bragg reflector pair
• CPC Class Codes: H10K 59/35 comprising red-green-blue [RGB] subpixels

Abstract

A microcavity OLED device including a substrate; a metallic bottom-electrode layer disposed over the substrate; a metallic top-electrode layer spaced from the metallic bottom-electrode layer; and an organic EL medium structure having a defined thickness, and including a light-emitting layer comprising a host material and at least one dopant disposed between the top-electrode layer and the bottom-electrode layer; wherein one of the metallic electrode layers is light transmissive and the other one is essentially opaque and reflective; wherein the material for reflective metallic electrode layer includes Ag, Au, Al, or alloys thereof, and the material for the light transmissive metallic electrode layer includes Ag, Au, or alloys thereof. The at least one dopant is selected to generate one of red, green, or blue light in the light-emitting layer. The defined thickness of the EL medium structure is selected so that the microcavity OLED device is tuned for emission of one of red, green, or blue light through the light transmissive electrode layer.

Claims

1. A microcavity OLED device having improved luminance efficiency and improved chromaticity of emitted light, comprising:

a) a substrate;

b) a microcavity having a selected cavity length defined over one substrate surface by, in sequence, a metallic bottom-electrode layer, an organic electroluminescent (EL) medium structure, and a metallic top-electrode layer,

wherein one of the metallic electrode layers is light transmissive and the other one is substantially opaque and reflective;

wherein the material for the light transmissive electrode layer includes Ag, Au, or alloys thereof, and the material for the opaque and reflective electrode layer includes Ag, Au, Al, or alloys thereof;

wherein the organic EL medium structure includes at least a light-emitting layer comprised of at least one organic host material and at least one dopant material dispersed in the at least one host material;

wherein the selected cavity length is provided by selection of a thickness of at least one of the organic layers;

wherein the at least one dopant material is selected from the class of fluorescent dyes consisting of derivatives of anthracene, tetracene, xanthene, perylene, rubrene, coumarin, rhodamine, and quinacridone, dicyanomethylenepyran compounds, thiopyran compounds, polymethine compounds, pyrilium and thiapyrilium compounds, fluorene derivatives, periflanthene derivatives, indenoperylene derivatives, bis(azinyl)amine boron compounds, bis(azinyl)methane compounds, and carbostyryl compounds, so that one of red, green, or blue light is generated in the light-emitting layer; and

wherein the selected cavity length of the microcavity OLED device is tuned to provide a resonance condition for emission of one of red, green, or blue light through the light transmissive electrode layer and having the improved luminance efficiency and the improved chromaticity.

2. The microcavity OLED device according to claim 1 wherein both the metallic electrode layers are Ag or Ag alloys and the thickness of the light transmissive electrode layer is between 10 nm and 30 nm.

3. The microcavity OLED device according to claim 1 wherein the bottom-electrode layer is light transmissive and the light is emitted through the substrate.

4. The microcavity OLED device according to claim 3 wherein the device further includes a high index of refraction absorption-reducing layer disposed between the light transmissive bottom-electrode layer and the substrate.

5. The microcavity OLED device according to claim 4 wherein the absorption-reducing layer has an index of refraction greater than 1.6.

6. The microcavity OLED device according to claim 4 wherein the material for the light transmissive electrode layer further includes Al, Cu, alloys thereof, or MgAg alloys with less than 50% Ag.

7. The microcavity OLED device according to claim 1 wherein the top-electrode layer is light transmissive and the light is emitted through the light transmissive top-electrode layer.

8. The microcavity OLED device according to claim 7 wherein the device further includes a high index of refraction absorption-reducing layer disposed over the light transmissive top-electrode layer.

9. The microcavity OLED device according to claim 8 wherein the absorption-reducing layer has an index of refraction greater than 1.6.

10. The microcavity OLED device according to claim 8 wherein the material for the light transmissive electrode further includes Al, Cu, alloys thereof, or MgAg alloys with less than 50% Ag.

11. The microcavity OLED device according to claim 1 wherein the bottom-electrode layer is the anode and the top-electrode layer is the cathode.

12. The microcavity OLED device according to claim 1 wherein the bottom-electrode layer is the cathode and the top-electrode layer is the anode.

13. The microcavity OLED device according to claim 1 wherein the organic EL medium structure further includes an electron-injecting layer.

14. The microcavity OLED device according to claim 13 wherein the electron-injecting layer is formed of a material selected from the group consisting of alkaline metals, alkaline earth metals, and organic materials doped with at least one of these metals.

15. The microcavity OLED device according to claim 1 wherein the organic EL medium structure further includes a hole-injecting layer.

16. The microcavity OLED device according to claim 15 wherein the hole-injecting layer is formed of a material selected from the group consisting of molybdenum oxide (MoOx), vanadium oxide (VOx), nickel oxide (NiOx), phthalocyanines, and plasma-deposited fluorocarbon (CFx).

17. The microcavity OLED device according to claim 1 wherein the device further includes a transparent electrically conductive phase-layer disposed over the metallic bottom-electrode layer.

18. The microcavity OLED device according to claim 17 wherein the selected cavity length is provided by selection of a thickness of the phase-layer.

19. The microcavity OLED device according to claim 1 wherein the at least one organic host material is selected to have a band gap energy level which is higher than a band gap energy level of the at least one fluorescent dye dopant material.

20. The microcavity OLED device according to claim 19 wherein the at least one organic host material is a hole-transporting host material.

21. The microcavity OLED device according to claim 19 wherein the at least one organic host material is an electron-transporting host material.

22. A microcavity OLED device having improved luminance efficiency and improved chromaticity of emitted light, comprising:

a) a substrate;

b) a microcavity having a selected cavity length defined over one substrate surface by, in sequence, a metallic bottom-electrode layer, an organic electroluminescent (EL) medium structure, and a metallic top-electrode layer,

wherein one of the metallic electrode layers is light transmissive and the other one is substantially opaque and reflective;

wherein the material for the light transmissive electrode layer includes Ag, Au, or alloys thereof, and the material for the opaque and reflective electrode layer includes Ag, Au, Al, or alloys thereof;

wherein the organic EL medium structure includes at least a light-emitting layer comprised of at least one organic host material and at least one dopant material dispersed in the at least one host material;

wherein the selected cavity length is provided by selection of a thickness of at least one of the organic layers;

wherein the at least one dopant material is selected from the class of phosphorescent compounds consisting of cyclometallated Ir(III) complexes, cyclometallated Pt(II) complexes, Pt(II) porphyrin complexes, and trivalent lanthanide complexes, so that one of red, green, or blue light is generated in the light-emitting layer; and

wherein the selected cavity of the microcavity OLED device is tuned to provide a resonance condition for emission of one of red, green, or blue light through the light transmissive electrode layer and having the improved luminance efficiency and the improved chromaticity.

23. The microcavity OLED device according to claim 22 wherein both the metallic electrode layers are Ag or Ag alloys and the thickness of the light transmissive electrode layer is between 10 nm and 30 nm.

24. The microcavity OLED device according to claim 22 wherein the bottom-electrode layer is light transmissive and the light is emitted through the substrate.

25. The microcavity OLED device according to claim 24 wherein the device further includes a high index of refraction absorption-reducing layer disposed between the light transmissive bottom-electrode layer and the substrate.

26. The microcavity OLED device according to claim 25 wherein the absorption-reducing layer has an index of refraction greater than 1.6.

27. The microcavity OLED device according to claim 25 wherein the material for the light transmissive electrode layer further includes Al, Cu, alloys thereof, or MgAg alloys with less than 50% Ag.

28. The microcavity OLED device according to claim 22 wherein the top-electrode layer is light transmissive and the light is emitted through the light transmissive top-electrode layer.

29. The microcavity OLED device according to claim 28 wherein the device further includes a high index of refraction absorption-reducing layer disposed over the light transmissive top-electrode layer.

30. The microcavity OLED device according to claim 29 wherein the absorption-reducing layer has an index of refraction greater than 1.6.

31. The microcavity OLED device according to claim 29 wherein the material for the light transmissive electrode further includes Al, Cu, alloys thereof, or MgAg alloys with less than 50% Ag.

32. The microcavity OLED device according to claim 22 wherein the bottom-electrode layer is the anode and the top-electrode layer is the cathode.

33. The microcavity OLED device according to claim 22 wherein the bottom-electrode layer is the cathode and the top-electrode layer is the anode.

34. The microcavity OLED device according to claim 22 wherein the organic EL medium structure further includes an electron-injecting layer.

35. The microcavity OLED device according to claim 34 wherein the electron-injecting layer is formed of a material selected from the group consisting of alkaline metals, alkaline earth metals, and organic materials doped with at least one of these metals.

36. The microcavity OLED device according to claim 22 wherein the organic EL medium structure further includes a hole-injecting layer.

37. The microcavity OLED device according to claim 36 wherein the hole-injecting layer is formed of a material selected from the group consisting of molybdenum oxide (MoOx), vanadium oxide (VOx), nickel oxide (NiOx), phthalocyanines, and plasma-deposited fluorocarbon (CFx).

38. The microcavity OLED device according to claim 22 wherein the device further includes a transparent electrically conductive phase-layer disposed over the metallic bottom-electrode layer.

39. The microcavity OLED device according to claim 38 wherein the selected cavity length is provided by selection of a thickness of the phase-layer.

40. The microcavity OLED device according to claim 22 wherein the at least one organic host material is selected to have a band gap energy level which is higher than a band gap energy level of the at least one fluorescent or phosphorescent dye dopant material.

41. The microcavity OLED device according to claim 40 wherein the at least one organic host material is a hole-transporting host material.

42. The microcavity OLED device according to claim 40 wherein the at least one organic host material is an electron-transporting host material.

43. The microcavity OLED device according to claim 22 wherein the phosphorescent cyclometallated Ir(III) complex is selected from fac-tris(2-phenylpyridinato-N,C^2′

)Iridium(III), bis(2-phenylpyridinato-N,C^2′

)Iridium(III)(acetylacetonate), bis(2-(2′

-benzothienyl)pyridinato-N,C^2′

)Iridium(III)(acetylacetonate), tris(1-phenylisoquinolinato-N,C^2′

)Iridium(III), or bis(2-(4,6-difluorophenyl)-pyridinato-N,C^2′

)Iridium(III)(picolinate).

44. The microcavity OLED device according to claim 22 wherein the phosphorescent cyclometallated Pt(II) complex includes cis-bis(2-phenylpyridinato-N,C^2′

)platinum(II), cis-bis(2-(2′

-thienyl)pyridinato-N,C^3′

)platinum(II), cis-bis(2-(2′

-thienyl)quinolinato-N,C^5′

)platinum(II), or (2-(4,6-difluorophenyl)pyridinato-NC^2′

) platinum (II) acetylacetonate.

45. The microcavity OLED device according to claim 22 wherein the phosphorescent Pt(II) porphyrin complex is 2,3,7,8,12,13,17,18-octaethyl-21H, 23H-porphine platinum(II).

46. The microcavity OLED device according to claim 22 wherein the phosphorescent trivalent lanthanide complex includes a Tb³⁺ complex or a Eu³⁺ complex.

47. The microcavity OLED device according to claim 42 wherein the at least one organic host material is selected to have the energy of its lowest triplet excited state at least about equal to or greater than that of the phosphorescent dopant.

48. The microcavity OLED device according to claim 22 wherein the at least one organic host material is a hole-transporting host material.

49. The microcavity OLED device according to claim 48 wherein the hole-transporting host material is a substituted tri-aryl amine compound.

50. The microcavity OLED device according to claim 48 wherein the hole-transporting host material is an aryl-substituted carbazole compound.

51. The microcavity OLED device according to claim 50 wherein the carbazole compound is 4,4′

-N,N′

-dicarbazole-biphenyl.

52. The microcavity OLED device according to claim 47 wherein the at least one organic host material is an electron-transporting host material.

53. The microcavity OLED device according to claim 52 wherein the electron-transporting host material is selected from the group consisting of aryl-substituted oxadiazoles, aryl-substituted triazoles, aryl-substituted phenanthrolines, and metal quinoxolates.

54. A full-color microcavity OLED display device including red, green, and blue subpixels and having improved luminance efficiency and improved chromaticity of red, green, and blue light emitted from corresponding subpixels, comprising:

a) a substrate;

b) a microcavity defined over one substrate surface by, in sequence, a metallic bottom-electrode layer, an organic electroluminescent (EL) medium structure, and a metallic top-electrode layer,

wherein the microcavity has a different selected cavity length for each of the red, green, and blue sub-pixels;

wherein one of the metallic electrode layers is light transmissive and the other one is substantially opaque and reflective;

wherein the material for the light transmissive electrode layer includes Ag, Au, or alloys thereof, and the material for the opaque and reflective electrode layer includes Ag, Au, Al, or alloys thereof;

wherein the organic EL medium structure includes at least a pixelated light-emitting layer comprised of at least one organic host material and at least one different dopant material dispersed in the at least one host material in correspondence with the red, green, and blue subpixels;

wherein the different selected cavity length is provided by selection of a thickness of at least one pixelated organic layer;

wherein the at least one dopant material is selected to generate red light, another at least one dopant material is selected to generate green light, and another at least one dopant material is selected to generate blue light in the light-emitting layer;

wherein each of the at least one dopant materials is selected from the class of fluorescent dyes consisting of derivatives of anthracene, tetracene, xanthene, perylene, rubrene, coumarin, rhodamine, and quinacridone, dicyanomethylenepyran compounds, thiopyran compounds, polymethine compounds, pyrilium and thiapyrilium compounds, fluorene derivatives, periflanthene derivatives, indenoperylene derivatives, bis(azinyl)amine boron compounds, bis(azinyl)methane compounds, and carbostyryl compounds;

or the class of phosphorescent compounds consisting of cyclometallated Ir(III) complexes, cyclometallated Pt(II) complexes, Pt(II) porphyrin complexes, and trivalent lanthanide complexes, so that one of red, green, or blue light is generated in the light-emitting layer; and

wherein each of the different selected cavity length is selected so that the microcavity of each of the red, green, and blue subpixels of the full-color microcavity OLED display device is tuned to provide a resonance condition for emission of red, green, or blue light, respectively, through the light transmissive electrode layer and having the improved luminance efficiency and the improved chromaticity.

55. The full-color microcavity OLED display device according to claim 54 wherein both the metallic electrode layers are Ag and the thickness of the light transmissive electrode layer is between 10 nm and 30 nm.

56. The full-color microcavity OLED display device according to claim 54 wherein both the bottom-emitting layer is light transmissive and the light is emitted through the substrate.

57. The full-color microcavity OLED display device according to claim 56 wherein the device further includes a high index of refraction absorption-reducing layer disposed between the light transmissive bottom-electrode layer and the substrate.

58. The full-color microcavity OLED display device according to claim 57 wherein the absorption-reducing layer has an index of refraction greater than 1.6.

59. The full-color microcavity OLED display device according to claim 57 wherein the material for the light transmissive electrode layer further includes Al, Cu, alloys thereof, or MgAg alloys with less than 50% Ag.

60. The full-color microcavity OLED display device according to claim 54 wherein the top-electrode layer is light transmissive and the light is emitted through the light transmissive top-electrode layer.

61. The full-color microcavity OLED display device according to claim 60 wherein the device further includes a high index of refraction absorption-reducing layer disposed over the light transmissive top-electrode layer.

62. The full-color microcavity OLED display device according to claim 61 wherein the absorption-reducing layer has an index of refraction greater than 1.6.

63. The full-color microcavity OLED display device according to claim 61 wherein the material for the light transmissive electrode further includes Al, Cu, alloys thereof, or MgAg alloys with less than 50% Ag.

64. The full-color microcavity OLED display device according to claim 54 wherein the bottom-electrode layer is the anode and the top-electrode layer is the cathode.

65. The full-color microcavity OLED display device according to claim 54 wherein the bottom-electrode layer is the cathode and the top-electrode layer is the anode.

66. The full-color microcavity OLED display device according to claim 64 wherein the organic EL medium structure further includes an electron-injecting layer.

67. The full-color microcavity OLED display device according to claim 66 wherein the electron-injecting layer is formed of a material selected from the group consisting of alkaline metals, alkaline earth metals, and organic materials doped with at least one of these metals.

68. The full-color microcavity OLED display device according to claim 54 wherein the organic EL medium structure further includes a hole-injecting layer.

69. The full-color microcavity OLED display device according to claim 68 wherein the hole-injecting layer is formed of a material selected from the group consisting of molybdenum oxide (MoOx), vanadium oxide (VOx), nickel oxide (NiOx), phthalocyanines, and plasma-deposited fluorocarbon (CFx).

70. The full-color microcavity OLED display device according to claim 54 wherein the device further includes a transparent electrically conductive and pixelated phase-layer disposed over the metallic bottom-electrode layer.

71. The full-color microcavity OLED display device according to claim 70 wherein the different selected cavity length is provided by selection of a different thickness of the pixelated phase-layer in correspondence with the red, green, and blue subpixels, respectively.

72. The full-color microcavity OLED display device according to claim 54 wherein the at least one organic host material is selected to have a band gap energy level which is higher than a band gap energy level of each of the selected fluorescent or phosphorescent dye dopant materials.

73. The full-color microcavity OLED display device according to claim 72 wherein the at least one organic host material is a hole-transporting host material.

74. The full-color microcavity OLED display device according to claim 72 wherein the at least one organic host material is an electron-transporting host material.