Intersystem crossing agents for efficient utilization of excitons in organic light emitting devices

• US 6,515,298 B2
• Filed: 07/25/2001
• Issued: 02/04/2003
• Est. Priority Date: 07/21/1999
• Status: Expired due to Term

• Current Assignee: The Trustees of Princeton University (Princeton University), University of Southern California
• Original Assignee: The Trustees of Princeton University (Princeton University), University of Southern California
• Inventors: Baldo, Marc A., Forrest, Stephen R., Thompson, Mark E.
• Primary Examiner(s): Lee, Eddie
• Assistant Examiner(s): RICHARDS, N DREW
• Application Number:
  US09/915,130
• Publication Number:
  US 20020008233A1
• Time in Patent Office: 559 Days
• Field of Search: 257/40, 257/87, 257/89, 257/102, 257/103, 438/22, 438/29, 438/47, 438/99, 313/498, 313/502, 313/503, 313/504, 313/506
• US Class Current: 257/40
• CPC Class Codes: H10K 2101/10 Triplet emission
• CPC Class Codes: H10K 2102/103 comprising indium oxides, e.g. ITO
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 50/121 for assisting energy transfer, e.g. sensitization
• CPC Class Codes: H10K 50/18 Carrier blocking layers
• CPC Class Codes: H10K 85/324 comprising aluminium, e.g. Alq3
• 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 85/348 comprising osmium
• 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

Abstract

Organic light emitting devices are described wherein the emissive layer comprises a host material containing a fluorescent or phosphorescent emissive molecule, which molecule is adapted to luminesce when a voltage is applied across the heterostructure, wherein an intersystem crossing molecule of optical absorption spectrum matched to the emission spectrum of the emissive molecule enhances emission efficiency.

Claims

1. An organic light emitting device, comprising:

an anode;

a cathode; and

an emissive layer between the anode and the cathode, wherein the emissive layer comprises a host material, a fluorescent emissive molecule present as a dopant in said host material, and an intersystem crossing agent which transfers energy to the fluorescent emissive molecule, wherein the fluorescent emissive molecule exhibits fluorescence when a voltage is applied across the anode and the cathode.

2. The device of claim 1, wherein the intersystem crossing agent comprises a phosphorescent organometallic compound.

3. The device of claim 2, wherein the phosphorescent organometallic compound includes a metal selected from the group consisting of tungsten, platinum, gold, iridium and osmium.

4. The device of claim 3, wherein the phosphorescent organometallic compound comprises iridium.

5. The device of claim 3, wherein the phosphorescent organometallic compound comprises platinum.

6. The device of claim 1, wherein the intersystem crossing agent is selected from the group consisting of acridines, acridones, brominated polycyclic aromatic compounds, anthraquinones, alpha-beta-diketones, phenazines, benzoquinones, biacetyls, fullerenes, thiophenes, pyrazines, quinoxalines and thianthrenes.

7. The device of claim 1, wherein the intersystem crossing agent comprises fac tris(2-phenylpyridine)iridium.

8. The device of claim 1, wherein the fluorescent emissive molecule comprises [2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-ylidene]propane-dinitrile].

9. The device of claim 1, wherein the host material comprises 4,4′

-N,N′

-dicarbazole-biphenyl.

10. The device of claim 1, the emissive layer further comprising a polarization molecule, present as a dopant in said host material and having a dipole moment.

54. The organic light emitting device of claim 1, wherein the host material comprises a polyvinylcarbazole.

11. An organic light emitting device, comprising:

an anode;

a cathode; and

an emissive layer between the anode and the cathode, wherein the emissive layer comprises a host material, a phosphorescent emissive molecule present as a dopant in said host material, and an intersystem crossing agent which transfers energy to the phosphorescent emissive molecule, wherein the phosphorescent emissive molecule exhibits phosphorescence when a voltage is applied across the anode and the cathode, and wherein the intersystem crossing agent is different from the phosphorescent emissive molecule.

12. The device of claim 11, wherein the phosphorescent emissive molecule exhibits phosphorescence from a triplet molecular excited state.

13. The device of claim 12, wherein the intersystem crossing agent comprises a phosphorescent organometallic compound.

14. The device of claim 13, wherein the phosphorescent organometallic compound includes a metal selected from the group consisting of tungsten, platinum, gold, iridium and osmium.

15. The device of claim 14, wherein the phosphorescent organometallic compound comprises iridium.

16. The device of claim 14, wherein the phosphorescent organometallic compound comprises platinum.

17. The device of claim 11, wherein the intersystem crossing agent is selected from the group consisting of acridines, acridones, brominated polycyclic aromatic compounds, anthraquinones, alpha-beta-diketones, phenazines, benzoquinones, biacetyls, fullerenes, thiophenes, pyrazines, quinoxalines and thianthrenes.

18. The device of claim 11, wherein the intersystem crossing agent comprises fac tris(2-phenylpyridine)iridium.

19. The device of claim 11, wherein the phosphorescent emissive molecule comprises platinum octaethyl porphyrin.

20. The device of claim 11, wherein the host material comprises 4,4′

-N,N′

-dicarbazole-biphenyl.

21. The device of claim 11, the emissive layer further comprising a polarization molecule, present as a dopant in said host material and having a dipole moment.

46. A display device incorporating at least one of the organic light emitting device of claim 20.

47. The display device of claim 46 wherein the display device is incorporated into a system selected from the group of systems consisting of a larger display, a vehicle, a computer, a television, a printer, a large area wall, theater or stadium screen, a billboard and a sign.

48. A display device incorporating at least one of the organic light emitting device of claim 11.

49. The display device of claim 48 wherein the display device is incorporated into a system selected from the group of systems consisting of a larger display, a vehicle, a computer, a television, a printer, a large area wall, theater or stadium screen, a billboard and a sign.

55. The organic light emitting device of claim 11, wherein the host material comprises a polyvinylcarbazole.

22. An organic light emitting device, comprising:

a hole transporting layer;

a thin layer over the hole transporting layer, wherein the thin layer comprises an intersystem crossing agent;

an electron transporting layer over the thin layer, wherein the electron transporting layer comprises a host material and an emissive molecule, present as a dopant in said host material, wherein the emissive molecule exhibits luminescence when a voltage is applied across the organic light emitting device.

23. The device of claim 22, wherein the emissive molecule is phosphorescent and exhibits phosphorescence from a triplet molecular excited state.

24. The device of claim 22, wherein the emissive molecule is fluorescent and exhibits fluorescence from a singlet molecular excited state.

25. The device of claim 22, wherein the intersystem crossing agent comprises a phosphorescent organometallic compound.

26. The device of claim 25, wherein the phosphorescent organometallic compound includes a metal selected from the group consisting of tungsten, platinum, gold, iridium and osmium.

27. The device of claim 26, wherein the phosphorescent organometallic compound comprises iridium.

28. The device of claim 26, wherein the phosphorescent organometallic compound comprises platinum.

29. The device of claim 22, wherein the intersystem crossing agent is selected from the group consisting of acridines, acridones, brominated polycyclic aromatic compounds, anthraquinones, alpha-beta-diketones, phenazines, benzoquinones, biacetyls, fullerenes, thiophenes, pyrazines, quinoxalines and thianthrenes.

30. The device of claim 22, wherein the intersystem crossing agent comprises fac tris(2-phenylpyridine)iridium.

31. The device of claim 22, wherein the intersystem crossing agent comprises 2,7diphenyl fluorenone.

32. The device of claim 22, wherein the host material comprises tris-(8-hydroxyquinoline)aluminum.

33. The device of claim 22, the electron transporting layer further comprising a polarization molecule, present as a dopant in said host material and having a dipole moment.

50. A display device incorporating at least one of the organic light emitting device of claim 22.

51. The display device of claim 50 wherein the display device is incorporated into a system selected from the group of systems consisting of a larger display, a vehicle, a computer, a television, a printer, a large area wall, theater or stadium screen, a billboard and a sign.

56. The organic light emitting device of claim 22, wherein the host material comprises a polyvinylcarbazole.

34. An organic light emitting device, comprising:

a hole transporting layer comprising a host material and an emissive molecule, present as a dopant in said host material, wherein the emissive molecule exhibits luminescence when a voltage is applied across the organic light emitting device;

a thin layer over the hole transporting layer, wherein the thin layer comprises an intersystem crossing agent; and

an electron transporting layer over the thin layer.

35. The device of claim 34, wherein the emissive molecule is phosphorescent and exhibits phosphorescence from a triplet molecular excited state.

36. The device of claim 34, wherein the emissive molecule is fluorescent and exhibits fluorescence from a singlet molecular excited state.

37. The device of claim 34, wherein the intersystem crossing agent comprises a phosphorescent organometallic compound.

38. The device of claim 37, wherein the phosphorescent organometallic compound includes a metal selected from the group consisting of tungsten, platinum, gold, iridium and osmium.

39. The device of claim 38, wherein the phosphorescent organometallic compound comprises iridium.

40. The device of claim 38, wherein the phosphorescent organometallic compound comprises platinum.

41. The device of claim 34, wherein the intersystem crossing agent is selected from the group consisting of acridines, acridones, brominated polycyclic aromatic compounds, anthraquinones, alpha-beta-diketones, phenazines, benzoquinones, biacetyls, fallerenes, thiophenes, pyrazines, quinoxalines and thianthrenes.

42. The device of claim 34, wherein the intersystem crossing agent comprises fac tris(2-phenylpyridine)iridium.

43. The device of claim 34, wherein the intersystem crossing agent comprises 2,7diphenyl fluorenone.

44. The device of claim 34, wherein the host material comprises 4,4′

-N,N′

-dicarbazole-biphenyl.

45. The device of claim 34, the hole transporting layer further comprising a polarization molecule, present as a dopant in said host material and having a dipole moment.

52. A display device incorporating at least one of the organic light emitting device of claim 34.

53. The display device of claim 52 wherein the display device is incorporated into a system selected from the group of systems consisting of a larger display, a vehicle, a computer, a television, a printer, a large area wall, theater or stadium screen, a billboard and a sign.

57. The organic light emitting device of claim 34, wherein the host material comprises a polyvinylcarbazole.