Providing an organic electroluminescent device having stacked electroluminescent units

• US 6,872,472 B2
• Filed: 02/15/2002
• Issued: 03/29/2005
• Est. Priority Date: 02/15/2002
• Status: Expired due to Term

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Liao, Liang-Sheng L., Tang, Ching W.
• Primary Examiner(s): Garrett, Dawn
• Application Number:
  US10/077,270
• Publication Number:
  US 20030170491A1
• Time in Patent Office: 1,138 Days
• Field of Search: 428/690, 428/917, 428/332, 313/504, 313/506, 257/88, 257/89, 257/96, 257/98, 257/102, 257/103, 427/66
• US Class Current: 428/690
• CPC Class Codes: H05B 45/60 Circuit arrangements for operating LEDs comprising organic material, e.g. for operating organic light-emitting diodes [OLED] or polymer light-emitting diodes [PLED]
• CPC Class Codes: H10K 2101/10 Triplet emission
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 50/125 specially adapted for multicolour light emission, e.g. for emitting white light
• CPC Class Codes: H10K 50/19 Tandem OLEDs
• CPC Class Codes: H10K 59/12 Active-matrix OLED [AMOLED] displays
• CPC Class Codes: H10K 59/17 Passive-matrix OLED displays
• CPC Class Codes: H10K 59/35 comprising red-green-blue [RGB] subpixels
• CPC Class Codes: H10K 59/38 comprising colour filters or colour changing media [CCM]
• CPC Class Codes: H10K 85/30 Coordination compounds
• CPC Class Codes: H10K 85/341 Transition metal complexes, e.g. Ru(II)polypyridine complexes H10K85/331 takes precedence
• CPC Class Codes: H10K 85/342 comprising iridium
• CPC Class Codes: H10K 85/351 Metal complexes comprising lanthanides or actinides, e.g. comprising europium
• CPC Class Codes: H10K 85/615 Polycyclic condensed aromatic hydrocarbons, e.g. anthracene
• 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: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
• CPC Class Codes: Y10S 428/917 Electroluminescent
• CPC Class Codes: Y10T 428/26 Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension

Abstract

A stacked organic electroluminescent device and a method of making such device is disclosed. The device comprises an anode, a cathode, at least two organic electroluminescent units disposed between the anode and the cathode, and a doped organic connector disposed between each adjacent organic electroluminescent unit wherein the organic electroluminescent unit comprises at least one organic hole-transporting layer and one organic electron-transporting layer. The doped organic connector comprises at least one n-type doped organic layer or one p-type doped organic layer, or combinations of layers thereof.

Claims

1. A stacked organic electroluminescent device comprising:

(a) an anode;

(b) a cathode;

(c) a plurality of organic electroluminescent units disposed between the anode and the cathode; and

(d) a doped organic connector disposed between each adjacent organic electroluminescent unit.

2. The stacked organic electroluminescent device of claim 1 wherein the organic electroluminescent units comprise non-polymeric materials.

3. The stacked organic electroluminescent device of claim 2 wherein the organic electroluminescent units comprise a hole-transporting layer and an electron-transporting layer.

4. The stacked organic electroluminescent device of claim 1 wherein the organic electroluminescent units comprise polymeric materials.

5. The stacked organic electroluminescent device of claim 4 wherein the organic electroluminescent units comprise a hole-transporting layer and a light-emitting layer.

6. The stacked organic electroluminescent device of claim 1 wherein all of the organic electroluminescent units are the same.

7. The stacked organic electroluminescent device of claim 1 wherein at least one of the organic electroluminescent units is different from at least one other.

8. The stacked organic electroluminescent device of claim 1 wherein there are at least three organic electroluminescent units and wherein the doped organic connectors comprise an n-type doped organic layer, a p-type doped organic layer, or combinations of layers thereof.

9. The stacked organic electroluminescent device of claim 8 wherein at least one of the doped organic connectors is different from at least one other doped organic connector.

10. The stacked organic electroluminescent device of claim 1 wherein at least one of the organic electroluminescent units comprises a triplet emitter.

11. The stacked organic electroluminescent device of claim 1 wherein the thickness of each organic electroluminescent unit is from 2 to 200 nm.

12. The stacked organic electroluminescent device of claim 1 wherein the thickness of the doped organic connector is from 1 to 100 nm.

13. A lamp for area lighting comprising:

(a) a transparent substrate; and

(b) the stacked organic electroluminescent device according to claim 1, wherein the organic electroluminescent device is provided over the transparent substrate and emits white light.

14. A full-color matrix display that is observable by a viewer comprising:

(a) a matrix array of stacked organic electroluminescent devices according to claim 8, wherein each device emits white light by stacking red, green, and blue-emitting organic electroluminescent units;

(b) means for independently electrically activating each device; and

(c) an array of red, green, and blue filters provided in registration with the devices and situated between the devices and the viewer.

15. A full-color matrix display that is observable by a viewer comprising:

(a) a matrix array of stacked organic electroluminescent devices according to claim 1, wherein each device emits white light by stacking blue and yellow-emitting organic electroluminescent units, or by stacking green and magenta-emitting organic electroluminescent units, or by stacking red and cyan-emitting organic electroluminescent units;

(b) means for independently electrically activating each device; and

(c) an array of red, green, and blue filters provided in registration with the devices and situated between the devices and the viewer.

16. A full-color matrix display that is observable by a viewer comprising:

(a) a matrix array of stacked organic electroluminescent devices according to claim 1, wherein each device emits blue light;

(b) means for independently electrically activating each device; and

(c) an array of blue-to-red, and blue-to-green color conversion filters provided in registration with the devices and situated between the devices and the viewer.

17. A full-color matrix display that is observable by a viewer comprising:

(a) a plurality of stacked organic electroluminescent devices according to claim 1 which form a matrix array of red, green, and blue-emitting stacked organic electroluminescent devices, wherein each device emits only red, green, or blue; and

(b) means for independently electrically activating each device.

18. A stacked organic electroluminescent device comprising:

(a) an anode;

(b) a cathode;

(c) a plurality of organic electroluminescent units disposed between the anode and the cathode; and

(d) a doped organic connector disposed between each adjacent organic electroluminescent unit wherein the doped organic connector comprises at least one n-type doped organic layer.

19. The stacked organic electroluminescent device of claim 18 wherein the n-type doped organic layer comprises at least one host organic material and at least one n-type dopant, wherein the host organic material is capable of supporting electron transport.

20. The stacked organic electroluminescent device of claim 19 wherein the host organic material of the n-type doped organic layer includes metal chelated oxinoid compounds, 8-hydroxyquinoline derivatives, butadiene derivatives, heterocyclic optical brighteners, triazines, benzazoles, or silole derivatives, or combinations thereof.

21. The stacked organic electroluminescent device of claim 19 wherein the n-type dopant in the n-type doped organic layer has a work function less than 4.0 eV.

22. The stacked organic electroluminescent device of claim 21 wherein the n-type dopant in the n-type doped organic layer comprises alkali metals, alkali metal compounds, alkaline earth metals, or alkaline metal compounds, or combinations thereof.

23. The stacked organic electroluminescent device of claim 19 wherein the n-type dopant in the n-type doped organic layer includes organic reducing agents with strong electron-donating properties such that they are capable of forming charge-transfer complexes with the organic host material.

24. The stacked organic electroluminescent device of claim 23 wherein the n-type dopant in the n-type doped organic layer includes bis(ethylenedithio)-tetrathiafulvalene (BEDT-TTF), tetrathiafulvalene (TTF), or their derivatives, or combinations thereof.

25. The stacked organic electroluminescent device of claim 19 wherein the n-type doped concentration is in the range of 0.01˜

10 vol. %.

26. The stacked organic electroluminescent device of claim 19 wherein the thickness of each organic electroluminescent unit is from 2 to 200 nm.

27. The stacked organic electroluminescent device of claim 19 wherein the thickness of each doped organic connector is from 1 to 100 nm.

28. The stacked organic electroluminescent device of claim 19 wherein the organic electroluminescent units comprise non-polymeric materials.

29. The stacked organic electroluminescent device of claim 28 wherein the organic electroluminescent units comprise a hole-transporting layer and an electron-transporting layer.

30. The stacked organic electroluminescent device of claim 19 wherein the organic electroluminescent units comprise polymeric materials.

31. The stacked organic electroluminescent device of claim 30 wherein the organic electroluminescent units comprise a hole-transporting layer and a light-emitting layer.

32. The stacked organic electroluminescent device of claim 19 comprising at least three organic electroluminescent units such that red, green, and blue-emitting units are combined to yield white light.

33. The stacked organic electroluminescent device of claim 19 wherein the organic electroluminescent units emit essentially the same color.

34. A stacked organic electroluminescent device comprising:

(a) an anode;

(b) a cathode;

(c) a plurality of organic electroluminescent units disposed between the anode and the cathode; and

(d) a doped organic connector disposed between each adjacent organic electroluminescent unit wherein the doped organic connector comprises at least one p-type doped organic layer.

35. The stacked organic electroluminescent device of claim 34 wherein the p-type doped organic layer comprises at least one host organic material and at least one p-type dopant, wherein the host organic material is capable of supporting hole transport.

36. The stacked organic electroluminescent device of claim 35 wherein the host organic material of the p-type doped organic layer includes aromatic tertiary amines having at least one trivalent nitrogen atom that is bonded only to carbon atoms, at least one of which is a member of an aromatic ring.

37. The stacked organic electroluminescent device of claim 35 wherein the p-type dopant in the p-type doped organic layer includes inorganic oxidizing agents capable of forming a charge transfer complex with the host material.

38. The stacked organic electroluminescent device of claim 37 where the p-type dopant in the p-type doped organic layer includes iodine, FeCl3, or SbCl5, or combinations thereof.

39. The stacked organic electroluminescent device of claim 35 wherein the p-type dopant in the p-type doped organic layer includes organic oxidizing agents with strong electron-withdrawing properties such as are capable of forming a charge transfer complex with the host material.

40. The stacked organic electroluminescent device of claim 39 wherein the p-type dopant in the p-type doped organic layer includes 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ) or other derivatives of TCNQ, or combinations thereof.

41. The stacked organic electroluminescent device of claim 35 wherein the p-type doped concentration is in the range of 0.01˜

10 vol. %.

42. The stacked organic electroluminescent device of claim 35 wherein the thickness of each organic electroluminescent unit is from 2 to 200 nm.

43. The stacked organic electroluminescent device of claim 35 wherein the thickness of each doped organic connector is from 1 to 100 nm.

44. The stacked organic electroluminescent device of claim 35 wherein the organic electroluminescent units comprise non-polymeric materials.

45. The stacked organic electroluminescent device of claim 44 wherein the organic electroluminescent units comprise a hole-transporting layer and an electron-transporting layer.

46. The stacked organic electroluminescent device of claim 35 wherein the organic electroluminescent units comprise polymeric materials.

47. The stacked organic electroluminescent device of claim 46 wherein the organic electroluminescent units comprise a hole-transporting layer and a light-emitting layer.

48. The stacked organic electroluminescent device of claim 35 comprising at least three organic electroluminescent units such that red, green, and blue-emitting units are combined to yield white light.

49. The stacked organic electroluminescent device of claim 35 wherein the organic electroluminescent units emit essentially the same color.

50. A stacked organic electroluminescent device comprising:

(a) an anode;

(b) a cathode;

(c) a plurality of organic electroluminescent units disposed between the anode and the cathode; and

(d) a doped organic connector disposed between each adjacent organic electroluminescent unit, wherein the doped organic connector comprises at least one n-type doped organic layer and one p-type doped organic layer.

51. The stacked organic electroluminescent device of claim 50 wherein the doped organic connector comprises an n-type doped organic layer and a p-type doped organic layer disposed adjacent to one another, wherein the n-type doped organic layer is disposed towards the anode side, and the p-type doped organic layer is disposed towards the cathode side.

52. The stacked organic electroluminescent device of claim 51 wherein the n-type doped organic layer comprises at least one host organic material and at least one n-type dopant, wherein the host organic material for the n-type doped organic layer is capable of supporting electron transport, and wherein the p-type doped organic layer comprises at least one host organic material and at least one p-type dopant, wherein the host organic material for the p-type doped organic layer is capable of supporting hole transport.

53. The stacked organic electroluminescent device of claim 52 wherein the host organic material of the n-type doped organic layer includes metal chelated oxinoid compounds, 8-hydroxyquinoline derivatives, butadiene derivatives, heterocyclic optical brighteners, triazines, benzazoles, or silole derivatives, or combinations thereof.

54. The stacked organic electroluminescent device of claim 52 wherein the n-type dopant in the n-type doped organic layer has a work function less than 4.0 eV.

55. The stacked organic electroluminescent device of claim 54 wherein the n-type dopant in the n-type doped organic layer comprises alkali metals, alkali metal compounds, alkaline earth metals, or alkaline metal compounds, or combinations thereof.

56. The stacked organic electroluminescent device of claim 52 wherein the n-type dopant in the n-type doped organic layer includes organic reducing agents with strong electron-donating properties, capable of forming charge-transfer complexes with the organic host material.

57. The stacked organic electroluminescent device of claim 56 wherein the n-type dopant in the n-type doped organic layer includes bis(ethylenedithio)-tetrathiafulvalene (BEDT-TTF), tetrathiafulvalene (TTF), or their derivatives, or combinations thereof.

58. The stacked organic electroluminescent device of claim 52 wherein the host organic material of the p-type doped organic layer includes aromatic tertiary amines having at least one trivalent nitrogen atom that is bonded only to carbon atoms, at least one of which is a member of an aromatic ring.

59. The stacked organic electroluminescent device of claim 52 wherein the p-type dopant in the p-type doped organic layer includes inorganic oxidizing agents capable of forming a charge transfer complex with the host material.

60. The stacked organic electroluminescent device of claim 59 where the p-type dopant in the p-type doped organic layer includes iodine, FeCl3, or SbCl5, or combinations thereof.

61. The stacked organic electroluminescent device of claim 52 wherein the p-type dopant in the p-type doped organic layer includes organic oxidizing agents with strong electron-withdrawing properties, capable of forming a charge transfer complex with the host material.

62. The stacked organic electroluminescent device of claim 61 wherein the p-type dopant in the p-type doped organic layer includes 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ) or other derivatives of TCNQ, or combinations thereof.

63. The stacked organic electroluminescent device of claim 52 wherein both the n-type and p-type doped concentration is in the range of 0.01˜

10 vol. %.

64. The stacked organic electroluminescent device of claim 52 wherein the thickness of each organic electroluminescent unit is from 2 to 200 nm.

65. The stacked organic electroluminescent device of claim 52 wherein the thickness of each doped organic connector is from 1 to 100 nm.

66. The stacked organic electroluminescent device of claim 52 wherein the organic electroluminescent units comprise non-polymeric materials.

67. The stacked organic electroluminescent device of claim 66 wherein the organic electroluminescent units comprise a hole-transporting layer and an electron-transporting layer.

68. The stacked organic electroluminescent device of claim 52 wherein the organic electroluminescent units comprise polymeric materials.

69. The stacked organic electroluminescent device of claim 68 wherein the organic electroluminescent units comprise a hole-transporting layer and an electron-transporting layer.

70. The stacked organic electroluminescent device of claim 52 comprising at least three organic electroluminescent units such that red, green, and blue-emitting units are combined to yield white light.

71. The stacked organic electroluminescent device of claim 52 wherein the organic electroluminescent units emit essentially the same color.

72. A method of making a stacked organic electroluminescent device having at least two organic electroluminescent units, comprising the steps of:

(a) providing a first organic electroluminescent unit connected to an anode, and a second organic electroluminescent unit connected to a cathode; and

(b) providing a doped organic connector to connect at least the first and second organic electroluminescent units, such doped organic connector disposed between each adjacent organic electroluminescent unit, whereby the stacked organic electroluminescent device includes only a single anode and cathode.

73. The method of claim 72 further including one or more intermediate organic electroluminescent unit(s) disposed between the first and second organic electroluminescent units, with each such intermediate organic electroluminescent unit being formed without an anode or a cathode and using a doped organic connector to secure such intermediate organic electroluminescent unit(s) within the stacked organic electroluminescent device.

74. The method according to claim 72 further including the step of selecting the organic electroluminescent units to provide improved luminance efficiency.

75. The method according to claim 74 wherein the number of organic electroluminescent units is selected to improve luminance efficiency.