Materials and structures for enhancing the performance of organic light emitting devices

• US 7,198,859 B2
• Filed: 07/25/2003
• Issued: 04/03/2007
• Est. Priority Date: 07/25/2003
• Status: Active Grant

• Current Assignee: Universal Display Corporation
• Original Assignee: Universal Display Corporation
• Inventors: Knowles, David B., Ma, Bin, Kwong, Raymond, Tung, Yeh-Jiun
• Primary Examiner(s): YAMNITZKY, MARIE ROSE
• Application Number:
  US10/626,730
• Publication Number:
  US 20050019605A1
• Time in Patent Office: 1,348 Days
• Field of Search: None
• US Class Current: 428/690
• CPC Class Codes: C09K 11/06 containing organic luminescent materials
• CPC Class Codes: C09K 2211/185 of the platinum group, i.e. Os, Ir, Pt, Ru, Rh or Pd
• CPC Class Codes: H05B 33/14 characterised by the chemical or physical composition or the arrangement of the electroluminescent material , or by the simultaneous addition of the electroluminescent material in or onto the light source
• CPC Class Codes: H10K 2101/10 Triplet emission
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 50/18 Carrier blocking layers
• CPC Class Codes: H10K 50/181 Electron blocking layers
• CPC Class Codes: H10K 85/321 Metal complexes comprising a group IIIA element, e.g. Tris (8-hydroxyquinoline) gallium [Gaq3]
• CPC Class Codes: Y10S 428/917 Electroluminescent
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree

Abstract

A device is provided, having an anode, a cathode, and a first organic layer disposed between the anode and the cathode. The first organic layer produces phosphorescent emission when a voltage is applied between the anode and the cathode. An organic enhancement layer disposed between the first organic layer and the cathode is also provided. The organic enhancement layer is in direct contact with the first organic layer. The organic enhancement layer may comprise a material of structure (I):

The material of structure I is thermally stable and is a high energy band gap material.

Claims

1. A device comprising,

an anode;

a cathode;

a first organic layer disposed between the anode and the cathode, wherein the first organic layer produces phosphorescent emission when a voltage is applied between the anode and the cathode; and

an organic enhancement layer disposed between the first organic layer and the cathode, wherein the organic enhancement layer is in physical contact with the first organic layer, and wherein the organic enhancement layer comprises a material having the structure;

2. The device of claim 1, wherein y is zero.

3. The device of claim 1, wherein R₃–

R₁₀ are each hydrogen.

4. The device of claim 1, wherein the organic enhancement layer comprises a material of Formula X having the structure:

5. The device of claim 1, wherein the organic enhancement layer comprises a material of Formula XI having the structure:

6. The device of claim 5, wherein the material of Formula XI has a glass transition temperature of at least about 108°

C.

7. The device of claim 5, wherein the material of Formula XI present in the device has a fluorescence peak at less than about 430 nm.

8. The device of claim 1, wherein the material has a glass transition temperature of at least about 95°

C.

9. The device of claim 1, wherein the material has a fluorescence peak at less than about 450 nm.

10. The device of claim 1, wherein the organic enhancement layer is in physical contact with the cathode.

11. The device of claim 1, further comprising an additional organic layer disposed between the organic enhancement layer and the cathode.

12. The device of claim 1, wherein the first organic layer comprises a hole transporting material.

13. The device of claim 12, wherein the organic enhancement material comprises a material having a lowest unoccupied molecular orbital energy level that is not more than 0.3 eV less than the energy level of the lowest unoccupied molecular orbital of the hole transporting material in the first organic layer.

14. The device of claim 13, wherein the organic enhancement material comprises a material having a lowest unoccupied molecular orbital energy level that is not more than 0.15 eV less than the energy level of the lowest unoccupied molecular orbital of the hole transporting material in the first organic layer.

15. The device of claim 12, wherein the organic enhancement material comprises a material having a lowest unoccupied molecular orbital energy level that is greater than the energy level of the lowest unoccupied molecular orbital of the hole transporting material in the first organic layer.

16. A device comprising

an anode;

a cathode;

a first organic layer disposed between the anode and the cathode, wherein the first organic layer produces phosphorescent emission when a voltage is applied between the anode and the cathode; and

an organic enhancement layer disposed between the first organic layer and the cathode, wherein the organic enhancement layer is in physical contact with the first organic layer, and wherein the organic enhancement layer comprises a material of Formula IX having the structure;

17. A device, comprising:

an anode;

a cathode;

a first organic layer disposed between the anode and the cathode, wherein the first organic layer produces phosphorescent emission when a voltage is applied between the anode and the cathode; and

an organic enhancement layer disposed between the first organic layer and the cathode, wherein the organic enhancement layer is in physical contact with the first organic layer, and wherein the organic enhancement layer comprises a material which comprises a ligand having the structure;

18. The device of claim 17, wherein R₃, R₄, R₅ and R₆ are each hydrogen.

19. The device of claim 17, wherein the first organic layer comprises a hole transporting material.

20. The device of claim 19, wherein the organic enhancement material comprises a material having a lowest unoccupied molecular orbital energy level that is not more than 0.3 eV less than the energy level of the lowest unoccupied molecular orbital of the hole transporting material in the first organic layer.

21. The device of claim 20, wherein the organic enhancement material comprises a material having a lowest unoccupied molecular orbital energy level that is not more than 0.15 eV less than the energy level of the lowest unoccupied molecular orbital of the hole transporting material in the first organic layer.

22. The device of claim 19, wherein the organic enhancement material comprises a material having a lowest unoccupied molecular orbital energy level that is greater than the energy level of the lowest unoccupied molecular orbital of the hole transporting material in the first organic layer.

23. A device comprising:

an anode;

a cathode;

a first organic layer disposed between the anode and the cathode, wherein the first organic layer produces phosphorescent emission when a voltage is applied between the anode and the cathode; and

an organic enhancement layer disposed between the first organic layer and the cathode, wherein the organic enhancement layer is in physical contact with the first organic layer, and wherein the organic enhancement layer comprises a material of Formula V having the structure;

24. The device of claim 23, wherein y is zero and x is the maximum number of ligands that may be attached to the metal M.

25. The device of claim 23, wherein R₃–

R₁₀ are each hydrogen.

26. The device of claim 23, wherein y is zero.

27. The device of claim 23, wherein the material has a glass transition temperature of at least about 95°

C.

28. The device of claim 23, wherein the material has a fluorescence peak at less than about 450 nm.

29. The device of claim 23, wherein the organic enhancement layer is in physical contact with the cathode.

30. The device of claim 23, further comprising an additional organic layer disposed between the organic enhancement layer and the cathode.

31. The device of claim 23, wherein the first organic layer comprises a hole transporting material.

32. The device of claim 31, wherein the organic enhancement material comprises a material having a lowest unoccupied molecular orbital energy level that is not more than 0.3 eV less than the energy level of the lowest unoccupied molecular orbital of the hole transporting material in the first organic layer.

33. The device of claim 32, wherein the organic enhancement material comprises a material having a lowest unoccupied molecular orbital energy level that is not more than 0.15 eV less than the energy level of the lowest unoccupied molecular orbital of the hole transporting material in the first organic layer.

34. The device of claim 31, wherein the organic enhancement material comprises a material having a lowest unoccupied molecular orbital energy level that is greater than the energy level of the lowest unoccupied molecular orbital of the hole transporting material in the first organic layer.

35. A device, comprising:

an anode;

a cathode;

a first organic layer disposed between the anode and the cathode, wherein the first organic layer produces phosphorescent emission when a voltage is applied between the anode and the cathode; and

an organic enhancement layer disposed between the first organic layer and the cathode, wherein the organic enhancement layer is in physical contact with the first organic layer, and wherein the organic enhancement layer comprises a material which comprises a ligand having the structure;