Binuclear compounds

• US 20040197600A1
• Filed: 04/01/2003
• Published: 10/07/2004
• Est. Priority Date: 04/01/2003
• Status: Active Grant

• Current Assignee: University of Southern California
• Original Assignee: University of Southern California
• Inventors: Thompson, Mark E., Djurovich, Peter, Alleyne, Bert
• Granted Patent: US 7,090,928 B2
• Time in Patent Office: Days
• US Class Current: 428/690
• 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 85/30 Coordination compounds
• CPC Class Codes: H10K 85/346 comprising platinum
• CPC Class Codes: H10K 85/361 Polynuclear complexes, i.e. complexes comprising two or more metal centers
• CPC Class Codes: H10K 85/633 comprising polycyclic condensed aromatic hydrocarbons as substituents on the nitrogen atom
• CPC Class Codes: H10K 85/657 Polycyclic condensed heteroaromatic hydrocarbons
• CPC Class Codes: Y10S 428/917 Electroluminescent

Abstract

Devices are provided having an anode, a cathode, and an emissive layer disposed between and electrically connected to the anode and the cathode. The emissive layer includes an emissive material having more than one metal center. In one embodiment, first and second metal centers are independently selected from the group consisting of d7, d8 and d9 metals. A bridging ligand is coordinated to the first metal center and to the second metal center. In one embodiment, the first and second metal centers each have coordination numbers of at least 3, and more preferably each have coordination numners of 4. In one embodiment, photoactive ligands are coordinated to the first and second metal centers. In one embodiment, there are no photoactive ligands. In one embodiment, a charge neutral bi-nuclear emissive material is provided. In one embodiment the first and metal centers have a co-facial configuration, and preferably a square planar co-facial configuration. In one embodiment, the metal centers are selected from metals having an atomic number greater than or equal to 40.

Claims

1. An organic light emitting device, comprising:

an anode;

a cathode; and

an emissive layer disposed between and electrically connected to the anode and the cathode, the emissive layer further comprising an emissive material comprising;

a first metal center selected from the group consisting of d7, d8 and d9 metals;

a second metal center selected from the group consisting of d7, d8 and d9 metals; and

a bridging ligand coordinated to the first metal center and to the second metal center.

2. The device of claim 1, wherein the first metal center and the second metal center are both selected from the group consisting of d8 metals.

3. The device of claim 2, wherein the distance between the first metal center and second metal center is such that there is significant overlap between a d8 orbital of the first metal center and a d8 orbital of the second metal center.

4. The device of claim 2, wherein the first metal center and the second metal center are both the same metal.

5. The device of claim 4, wherein the first metal center and the second metal center are both Pt.

6. The device of claim 1, wherein the emissive material is a binuclear material that comprises:

a first metal center;

a second metal center; and

four bridging ligands, wherein each bridging ligand is coordinated to the first metal center and to the second metal center.

7. The device of claim 1, wherein the emissive material is a binuclear material that comprises:

a first metal center;

a second metal center;

two bridging ligands, wherein each bridging ligand is coordinated to the first metal center and to the second metal center;

a first bidentate photoactive ligand bound to the first metal center, and

a second bidentate photoactive ligand bound to the second metal center.

8. The device of claim 7, wherein the first photoactive ligand and the second photoactive ligand are held in proximity by the bridging ligand and the first and second metal centers allowing for a significant π

-π

interaction between the first and second photoactive ligands.

9. The device of claim 8, wherein the first and second photoactive ligands have the same structure.

10. The device of claim 1, wherein the emissive material is a binuclear material that comprises:

a first metal center;

a second metal center;

one bridging ligand, wherein the bridging ligand is coordinated to the first metal center and to the second metal center;

a first tridentate photoactive ligand bound to the first metal center, and

a second tridentate photoactive ligand bound to the second metal center.

11. The device of claim 10, wherein the first photoactive ligand and the second photoactive ligand are held in proximity by the bridging ligand and the first and second metal centers allowing for a significant π

-π

interaction between the first and second photoactive ligands.

12. The device of claim 11, wherein the first and second photoactive ligands have the same structure.

13. The device of claim 1, wherein the emissive layer further comprises a host material, and the emissive material is present as a dopant in the host material.

14. The device of claim 1, wherein the device comprises

an anode;

a hole transporting layer;

an electron transporting layer;

a cathode;

and an emissive layer, wherein the emissive layer is disposed between the hole transporting layer and the electron transporting layer.

15. The device of claim 1, wherein the device substantially all of the light emitted from the device results from excimer emission.

16. The device of claim 1, wherein the emissive molecule is a phosphorescent emissive material.

17. The device of claim 7, wherein the first and second photoactive ligands have the following partial structure:

18. The device of claim 1, wherein each bridging ligand is selected from the group consisting of carboxylates (RCOO⁻

), thiocarboxyloic acids (RCSS⁻

), pyrophosphate (⁻

O₃P—

O—

PO₃⁻

), or a compound of the formula

19. The device of claim 1, wherein the bridging ligand is selected from the group consisting of:

20. The device of claim 19, wherein N and N′

include heteroatoms.

21. The device of claim 1, wherein the emissive molecule has the structure:

22. The device of claim 1, wherein the distance between the first metal center and the second metal center is less than about 4 angstroms.

23. The device of claim 22, wherein the distance between the first metal center and the second metal center is about 2.5 angstroms to about 2.8 angstroms.

24. The device of claim 1, wherein the emissive material does not include a photoactive ligand.

25. An organic light emitting device, comprising:

an anode;

a cathode; and

an emissive layer disposed between and electrically connected to the anode and the cathode, the emissive layer further comprising a binuclear emissive material comprising;

a first metal center having a coordination number of at least 3;

a second metal center having a coordination number of at least 3; and

a bridging ligand coordinated to the first metal center and to the second metal center.

26. The device of claim 25, wherein the first metal center and the second metal center both have a coordination number of at least 4.

27. The device of claim 26, wherein the first metal center and the second metal center both have a coordination number of 4.

28. The device of claim 25, wherein the emissive material does not include a photoactive ligand.

29. The device of claim 25, wherein:

the first metal center and the second metal center have the same coordination number; and

the emissive material further comprises a plurality of bridging ligands coordinated to the first metal center and the second metal center, such that the number of bridging ligands is equal to the coordination number of the first metal center.

30. An organic light emitting device, comprising:

an anode;

a cathode; and

an emissive layer disposed between and electrically connected to the anode and the cathode, the emissive layer further comprising a binuclear emissive material comprising;

a first metal center;

a second metal center;

a bridging ligand coordinated to the first metal center and to the second metal center;

a first photoactive ligand coordinated to the first metal center;

a second photoactive ligand coordinated to the second metal center.

31. The device of claim 30, wherein the first and second photoactive ligands have the following partial structure:

32. The device of claim 30, wherein each bridging ligand is selected from the group consisting of carboxylates (RCOO⁻

), thiocarboxyloic acids (RCSS⁻

), pyrophosphate (⁻

O₃P—

O—

PO₃⁻

), or a compound of the formula

33. The device of claim 30, wherein the bridging ligand is selected from the group consisting of:

34. The device of claim 33, wherein N and N′

include heteroatoms.

35. An organic light emitting device, comprising:

an anode;

a cathode; and

an emissive layer disposed between and electrically connected to the anode and the cathode, the emissive layer further comprising a binuclear emissive material comprising;

a first metal center;

a second metal center; and

a bridging ligand coordinated to the first metal center and to the second metal center;

wherein the binuclear emissive material is charge neutral.

36. An organic light emitting device, comprising:

an anode;

a cathode; and

an emissive layer disposed between and electrically connected to the anode and the cathode, the emissive layer further comprising a binuclear emissive material comprising;

a first metal center;

a second metal center; and

a bridging ligand coordinated to the first metal center and to the second metal center;

wherein the metal centers are held in a co-facial configuration by the bridging ligand.

37. The device of claim 36, wherein the first and second metal centers each have a square planar configuration.

38. An organic light emitting device, comprising:

an anode;

a cathode; and

an emissive layer disposed between and electrically connected to the anode and the cathode, the emissive layer further comprising an emissive material comprising;

a first metal center selected from the group consisting of metals having an atomic number greater than or equal to 40;

a second metal center selected from the group consisting of metals having an atomic number greater than or equal to 40; and

a bridging ligand coordinated to the first metal center and to the second metal center.