WHITE LIGHT-EMITTING DEVICE WITH IMPROVED DOPING

• US 20050048311A1
• Filed: 08/20/2003
• Published: 03/03/2005
• Est. Priority Date: 08/20/2003
• Status: Active Grant

• Current Assignee: Global OLED Technology LLC (LG Display Co., Ltd.)
• Original Assignee: Eastman Kodak Company
• Inventors: Hatwar, Tukaram K., Brown, Christopher T., Young, Ralph H.
• Granted Patent: US 6,875,524 B2
• Time in Patent Office: Days
• US Class Current: 428/690
• CPC Class Codes: H10K 50/13 comprising stacked EL layers within one EL unit
• CPC Class Codes: H10K 50/14 Carrier transporting layers
• CPC Class Codes: H10K 50/155 comprising dopants
• CPC Class Codes: H10K 50/156 comprising a multilayered structure
• CPC Class Codes: Y10S 428/917 Electroluminescent

Abstract

Organic light-emitting diodes (OLEDs) that produce white light include an anode, a hole-transporting layer disposed over the anode, a blue light-emitting layer disposed over the hole-transporting layer, an electron-transporting layer disposed over the blue light-emitting layer, and a cathode disposed over the electron-transporting layer. The hole-transporting layer is doped with both a yellow-emitting and a red-emitting dopant. When used together with red, green, and blue color filters, the OLEDs produce red, green, and blue light with good color quality and high efficiency. Also disclosed are multicolor display devices utilizing the OLEDs together with color filters or together with both color filters and liquid-crystal light valves.

Claims

1. An organic light-emitting diode (OLED) device that produces white light, including:

a) an anode;

b) a hole-transporting layer disposed over the anode;

c) a blue light-emitting layer disposed over the hole-transporting layer;

d) an electron-transporting layer disposed over the blue light-emitting layer;

e) a cathode disposed over the electron-transporting layer; and

f) the hole-transporting layer including a host material, a yellow dopant, and a red dopant.

2. The OLED of claim 1 wherein the blue light-emitting layer includes a host material and a blue dopant.

3. The OLED of claim 2 wherein the host material in the blue light-emitting layer includes an anthracene derivative having hydrocarbon or substituted-hydrocarbon substituents at the 9 and 10 positions.

4. The OLED of claim 2 wherein the host material includes 9,10-di-(2-naphthyl)anthracene (ADN) or 2-t-butyl-9,10-di-(2-naphthyl)anthracene (TBADN).

5. The OLED of claim 2 wherein the blue dopant includes perylene or a derivative of perylene.

6. The OLED of claim 2 wherein the blue dopant includes 2,5,8,11-tetra-t-butyl perylene (TBP).

7. The OLED of claim 2 wherein the blue dopant includes a blue-emitting derivative of a distyrylbenzene or a distyrylbiphenyl.

8. The OLED of claim 2 wherein the blue dopant includes a bis[2-[4-[N,N-diarylamino]phenyl]vinyl]arene.

9. The OLED of claim 2 wherein the blue dopant includes 1,4-bis[2-[4-[N,N-di(p-tolyl)amino]phenyl]vinyl]benzene (BDTAPVB).

10. The OLED of claim 2 wherein the blue dopant includes a compound of the structure

11. The OLED of claim 2 wherein the blue dopant includes a compound of the structure:

12. The OLED of claim 2 wherein the blue dopant includes a compound of the structure:

13. The OLED of claim 2 wherein the blue dopant is between 0.1 and 10% by volume of the blue light-emitting layer.

15. The OLED of claim 1 wherein the blue light-emitting layer includes NPB or TNB as a dopant.

16. The OLED of claim 1 wherein the hole-transporting layer includes a tertiary aromatic amine.

17. The OLED of claim 1 wherein the yellow dopant includes a compound of the following structure:

18. The OLED of claim 1 wherein the yellow dopant includes 5,6,11,12-tetraphenylnaphthacene (rubrene);

6,11-diphenyl-5,12-bis(4-(6-methyl-benzothiazol-2-yl)phenyl)naphthacene (DBzR);

or 5,6,11,12-tetra(2-naphthyl)naphthacene (NR).

19. The OLED of claim 1 wherein the red dopant includes a diindenoperylene compound of the following structure:

20. The OLED of claim 1 wherein the red dopant includes:

21. The OLED of claim 1 wherein the red dopant compound includes TPDBP.

22. The OLED of claim 1 wherein the red dopant includes a compound of the following structure:

23. The OLED of claim 1 wherein the red dopant includes:

24. The OLED of claim 1 wherein the red dopant is DCJTB.

25. The OLED of claim 1 wherein the yellow dopant is between 0.5 and 50% by volume of the hole-transporting layer.

26. The OLED of claim 1 wherein the red dopant is between 0.1 and 5% by volume of the hole-transporting layer.

27. The OLED of claim 1 wherein the hole-transporting layer includes two or more hole-transporting sub layers, the sublayer closest to the blue light-emitting layer including a host material, a yellow dopant, and a red dopant;

and the sublayer closest to the anode not containing the yellow dopant or not containing the red dopant.

28. The OLED of claim 27 wherein the concentration of the yellow dopant is between 0.5 and 50% by volume of the hole-transporting sublayer that is closest to the blue light-emitting layer.

29. The OLED of claim 27 wherein the concentration of the red dopant is between 0.1 and 5% by volume of the hole-transporting sublayer that is closest to the blue light-emitting layer.

30. The OLED of claim 1 wherein the electron-transporting layer includes a green dopant.

31. The OLED of claim 1 wherein the electron-transporting layer includes a coumarin compound.

32. The OLED of claim 1 wherein the electron-transporting layer includes C545T.

33. The OLED of claim 1 wherein the electron-transporting layer includes a quinacridone.

34. The OLED of claim 1 wherein the electron-transporting layer includes:

35. The OLED of claim 1 wherein the electron-transporting layer includes:

36. The OLED of claim 1 wherein the electron-transporting layer includes two or more electron-transporting sublayers, the sublayer adjacent to the blue light-emitting layer including a green dopant, and the sublayer adjacent to the cathode not containing the green dopant.

37. The OLED of claim 1 wherein the electron-transporting layer includes a red dopant.

38. The OLED of claim 1 wherein the electron-transporting layer includes a diindenoperylene compound of the following structure:

39. The OLED of claim 1 wherein the electron-transporting layer includes:

40. The OLED of claim 1 wherein the electron-transporting layer includes TPDBP.

41. The OLED of claim 1 wherein the electron-transporting layer includes a compound of the following structure:

42. The OLED of claim 1 wherein the electron-transporting layer includes:

43. The OLED of claim 1 wherein the electron-transporting layer includes DCJTB.

14. The OLED of claim I wherein the blue light-emitting layer includes a triarylamine dopant.

44. A light-emitting display including:

a) a plurality of OLEDs that produce white light when current is driven through them, each OLED including;

i) an anode;

ii) a hole-transporting layer disposed over the anode;

iii) a blue light-emitting layer disposed over the hole-transporting layer;

iv) an electron-transporting layer disposed over the blue light-emitting layer;

v) a cathode disposed over the electron-transporting layer; and

vi) the hole-transporting layer including a host material, a yellow dopant and a red dopant; and

b) an array of color filters, including red, green, and blue filters, disposed in the display, each filter corresponding to a different OLED such that the white light produced by each OLED is filtered by its corresponding filter.

45. The display of claim 44 further including a substrate, wherein the color filter array is disposed above the substrate and the anode is disposed above the color filter array, or wherein the anode is disposed over the substrate and the color filter array is disposed above the cathode.

46. A light-emitting display including:

a) one or more OLEDs that produce white light upon passage of electrical current through the OLED(s), each OLED including;

i) an anode;

ii) a hole-transporting layer disposed over the anode;

iii) a blue light-emitting layer disposed over the hole-transporting layer;

iv) an electron-transporting layer disposed over the blue light-emitting layer;

v) a cathode disposed over the electron-transporting layer; and

vi) the hole-transporting layer including a host material, a yellow dopant and a red dopant; and

b) an array of color filters, including red, green, and blue filters, disposed in the display such that the white light produced by the OLED(s) is filtered through the color filters; and

c) an array of liquid-crystal light valves, each light valve corresponding to a different color filter, disposed in the array such that the white light produced by the OLED(s) and filtered by the color filter is adjusted in brightness by the liquid-crystal light valves.