Solid state light-emitting device

• US 6,548,836 B1
• Filed: 04/29/1999
• Issued: 04/15/2003
• Est. Priority Date: 04/29/1999
• Status: Expired due to Fees

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Rubner, Michael F., Handy, Erik S., Pal, Amlan J.
• Primary Examiner(s): Lee, Eddie
• Assistant Examiner(s): RICHARDS, NORMAN DREW
• Application Number:
  US09/303,101
• Time in Patent Office: 1,447 Days
• Field of Search: 257/40, 257/103, 257/613, 257/82, 428/917, 428/690
• US Class Current: 257/103
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 85/344 comprising ruthenium
• CPC Class Codes: Y10S 428/917 Electroluminescent

Abstract

A solid state light-emitting device having a high maximum luminance, a high external efficiency, and a low operating voltage is described. The device can include a solid layer, a first inert electrode, and a second inert electrode. The solid layer includes a metal complex and has a first surface and a second surface. The first inert electrode contacts the first surface of the solid layer. The second inert electrode contacts the second surface of the solid layer. The device can have a luminance of at least 50 cd/m² at a potential of between 2.5 and 5.0 V.

Claims

1. A solid state light-emitting device comprising:

a homogeneous non-solvent-swollen-charged solid layer including a metal complex, said solid layer having a first surface and a second surface;

a first inert electrode in contact with said first surface; and

a second inert electrode in contact with said second surface;

wherein said device has a luminance of at least 50 cd/m² at a potential of between 2.5 and 5.0V.

2. The device of claim 1, wherein said metal complex is a transition metal complex.

3. The device of claim 1, wherein said device has a luminance of at least 100 cd/m² at a potential of between 2.5 and 5.0 V.

4. The device of claim 1, wherein said device has a luminance of at least 200 cd/m² at a potential of between 2.5 and 5.0 V.

5. The device of claim 1, wherein said device has an intensity drop to one-half of a maximum intensity at 2.8 V of at least 5 hours.

6. The device of claim 1, wherein said device has an intensity drop to one-half of a maximum intensity at 2.8 V of at least 20 hours.

7. The device of claim 1, wherein said device has an external efficiency of at least 0.5 percent.

8. The device of claim 1, wherein the metal is ruthenium.

9. The device of claim 1, wherein the metal is osmium.

10. The device of claim 1, wherein the metal complex is a bipyridine complex.

16. The device of claim 1, wherein said first inert electrode is selected from a group consisting of indium tin oxide, aluminum, silver, gold, platinum, and palladium.

17. The device of claim 16, wherein said second inert electrode is selected from a group consisting of indium tin oxide, silver, gold, platinum, palladium, and polypyrrole.

11. A solid state light-emitting device comprising:

a solid layer including a metal complex, said solid layer having a first surface and a second surface, wherein the metal complex is a bipyridine complex and the bipyridine has a hydroxymethyl substituent, a C1-18 alkoxycarbonyl substituent, or a hydroxy substituent;

a first inert electrode in contact with said first surface; and

a second inert electrode in contact with said second surface;

wherein said device has a luminance of at least 50 cd/M² at a potential of between 2.5 and 5.0 V.

12. The device of claim 11, wherein the bipyridine has a C-18alkoxycarbonyl substituent.

13. The device of claim 11, wherein the bipyridine has a hydroxy substituent.

40. The device of claim 11, wherein the bipyridine has a hydroxymethyl substituent.

14. A solid state light-emitting device comprising:

a solid layer including a metal complex, said solid layer having a first surface and a second surface, wherein the metal complex is non-polymeric;

a first inert electrode in contact with said first surface; and

a second inert electrode in contact with said second surface;

wherein said device has a luminance of at least 50 cd/m² at a potential of between 2.5 and 5.0 V.

15. The device of claim 14, wherein the metal complex is a hexafluorophosphate salt of a ruthenium bipyridine complex.

18. A solid state light emitting device comprising a solid layer consisting essentially of a non-polymeric ruthenium bipyridine complex.

19. The device of claim 18, wherein said device has a luminance of at least 50 cd/m² at a potential of between 2.5 and 5.0 V.

20. A solid state light emitting device comprising a solid layer consisting essentially of a ruthenium bipyridine complex, wherein the bipyridine has a hydroxymethyl substituent, a C1∝

18 alkoxycarbonyl substituent, or a hydroxy substituent.

21. The device of claim 20, wherein the bipyridine has a C-8 alkoxycarbonyl substituent.

22. The device of claim 20, wherein the bipyridine has a hydroxy substituent.

41. The device of claim 20, wherein the bipyridine has a hydroxymethyl substituent.

23. A solid state light emitting device comprising a solid layer including a non-polymeric metal bipyridine complex, said device having a luminance of at least 50 cd/m² at a potential of between 2.5 and 5.0 V.

24. The device of claim 23, wherein said metal bipyridine complex is a transition metal bipyridine complex.

25. The device of claim 24, wherein the transition metal is ruthenium.

26. The device of claim 23, wherein said device has a luminance of at least 100 cd/M² at a potential of between 2.5 and 5.0 V.

27. The device of claim 23, wherein said device has an intensity drop to one-half of a maximum intensity at 2.8 V of at least 5 hours.

28. The device of claim 23, wherein said device has an external efficiency of at least 0.5 percent.

29. The device of claim 23, wherein the metal bipyridine complex is a hexafluorophosphate salt of a ruthenium bipyridine complex.

30. A method of generating light comprising:

applying a light-generating potential of between 2.5 and 5.0 V across a first inert electrode and a second inert electrode of a solid state light-emitting device including a solid layer including a metal complex, said solid layer having a first surface and a second surface, said first inert electrode contacting said first surface, and said second inert electrode contacting with said second surface; and

generating light from the device having a luminance of at least 50 cd/m².

31. The method of claim 30, further comprising the step of applying a charging potential of greater than 5.0 V for less than 30 seconds prior to applying the light-generating potential.

32. The method of claim 30, wherein said metal complex is a transition metal complex.

33. The method of claim 30, wherein the metal is ruthenium.

34. The method of claim 33, wherein the metal complex is a bipyridine complex.

35. A method of generating light comprising:

applying a light-generating potential of between 2.5 and 5.0 V across a first inert electrode and a second inert electrode of a solid state light-emitting device including a solid layer including a metal complex, wherein the metal complex is non-polymeric, said solid layer having a first surface and a second surface, said first inert electrode contacting said first surface, and said second inert electrode contacting with said second surface; and

generating light from the device having a luminance of at least 50 cd/m².

36. The method of claim 35, wherein the metal complex is a hexafluorophosphate salt of a ruthenium bipyridine complex.

37. The method of claim 36, wherein said light from the device has a luminance of at least 100 cd/m².

38. The method of claim 36, wherein said light from the device has an intensity drop to one-half of a maximum intensity at 2.8 V of at least 5 hours.

39. The method of claim 36, wherein said device has an external efficiency of at least 0.5 percent.

42. A solid state light-emitting device comprising:

an encapsulated solid layer including a metal complex, said solid layer having a first surface and a second surface;

a first inert electrode in contact with said first surface; and

a second inert electrode in contact with said second surface;

wherein said device has a luminance of at least 50 cd/m² at a potential of between 2.5 and 5.0 V.