Organometallic complexes as phosphorescent emitters in organic LEDs

• US 6,830,828 B2
• Filed: 06/18/2001
• Issued: 12/14/2004
• Est. Priority Date: 09/14/1998
• 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., Lamansky, Sergey, Djurovich, Peter, Burrows, Paul E., Forrest, Stephen R., Thompson, Mark E.
• Primary Examiner(s): YAMNITZKY, MARIE ROSE
• Application Number:
  US09/883,734
• Publication Number:
  US 20020034656A1
• Time in Patent Office: 1,275 Days
• Field of Search: 428/690, 428/917, 313/504, 313/506, 252/301.16, 257/102, 257/103
• US Class Current: 428/690
• CPC Class Codes: C07D 209/86 with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, directly attached to carbon atoms of the ring system
• CPC Class Codes: C09K 11/06 containing organic luminescent materials
• CPC Class Codes: C09K 2211/1007 Non-condensed systems
• CPC Class Codes: C09K 2211/1014 bridged by heteroatoms, e.g. N, P, Si or B
• CPC Class Codes: C09K 2211/1029 containing one nitrogen atom as the heteroatom
• CPC Class Codes: C09K 2211/1033 with oxygen
• CPC Class Codes: C09K 2211/1037 with sulfur
• CPC Class Codes: C09K 2211/1092 containing sulfur as the only heteroatom
• CPC Class Codes: C09K 2211/185 of the platinum group, i.e. Os, Ir, Pt, Ru, Rh or Pd
• CPC Class Codes: C09K 2211/186 of the light metals other than alkali metals and alkaline earth metals, i.e. Be, Al or Mg
• 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 2102/103 comprising indium oxides, e.g. ITO
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 50/18 Carrier blocking layers
• CPC Class Codes: H10K 85/146 poly N-vinylcarbazol; Derivatives thereof
• CPC Class Codes: H10K 85/30 Coordination compounds
• CPC Class Codes: H10K 85/324 comprising aluminium, e.g. Alq3
• CPC Class Codes: H10K 85/342 comprising iridium
• CPC Class Codes: H10K 85/346 comprising platinum
• 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 85/633 : comprising polycyclic condensed aromatic hydrocarbons as substituents on the nitrogen atom
• CPC Class Codes: H10K 85/649 : Aromatic compounds comprising a hetero atom
• CPC Class Codes: H10K 85/653 : comprising only oxygen as heteroatom
• CPC Class Codes: H10K 85/654 : comprising only nitrogen as heteroatom H10K85/652 takes precedence
• CPC Class Codes: H10K 85/655 : comprising only sulfur as heteroatom
• CPC Class Codes: H10K 85/657 : Polycyclic condensed heteroaromatic hydrocarbons
• CPC Class Codes: H10K 85/6572 : comprising only nitrogen in the heteroaromatic polycondensed ring system, e.g. phenanthroline or carbazole
• CPC Class Codes: Y10S 428/917 : Electroluminescent

Abstract

Organic light emitting devices are described wherein the emissive layer comprises a host material containing an emissive molecule, which molecule is adapted to luminesce when a voltage is applied across the heterostructure, and the emissive molecule is selected from the group of phosphorescent organometallic complexes, including cyclometallated platinum, iridium and osmium complexes. The organic light emitting devices optionally contain an exciton blocking layer. Furthermore, improved electroluminescent efficiency in organic light emitting devices is obtained with an emitter layer comprising organometallic complexes of transition metals of formula L₂MX, wherein L and X are distinct bidentate ligands. Compounds of this formula can be synthesized more facilely than in previous approaches and synthetic options allow insertion of fluorescent molecules into a phosphorescent complex, ligands to fine tune the color of emission, and ligands to trap carriers.

Claims

1. An organic light emitting device comprising an anode, a cathode and an emissive layer, wherein the emissive layer is located between the anode and the cathode and the emissive layer comprises a phosphorescent organometallic compound, wherein the phosphorescent organometallic compound is an iridium compound including a carbon-metal bond.

2. The organic light emitting device of claim 1, wherein the iridium compound includes a cyclometallated ring having a carbon-metal bond.

3. The organic light emitting device of claim 1, wherein the iridium compound is fac-tris(2-phenylpyridine) iridium, as denoted by the formula:

4. The organic light emitting device of claim 1, wherein the phosphorescent organometallic compound is a cyclometallated compound including a cycle closed with at least one metal-X bond, wherein X is selected from the group consisting of nitrogen, sulfur, phosphorous, arsenic and oxygen, and including a cycle closed with at least one carbon-metal bond.

5. The organic light emitting device of claim 4, wherein X is nitrogen.

6. The organic light emitting device of claim 1, wherein the iridium compound is denoted by the formula:

wherein R is an alkyl or aryl group.

7. The organic light emitting device of claim 6, wherein the R group an alkyl group.

8. The organic light emitting device of claim 6, wherein the R group is an aryl group.

9. An organic light emitting device comprising an anode, a cathode and an emissive layer, wherein the emissive layer is located between the anode and the cathode, and the emissive layer comprises a host material and a phosphorescent organometallic compound present as a dopant in said host material, wherein the phosphorescent organometallic compound includes a carbon-metal bond and is selected from the group consisting of osmium compounds including a cyclometallated ring having a carbon-metal bond, iridium compounds and platinum compounds.

10. The organic light emitting device of claim 9, wherein the phosphorescent organometallic compound is an iridium compound.

11. The organic light emitting device of claim 10, wherein the iridium compound includes a cyclometallated ring having a carbon-metal bond.

12. The organic light emitting device of claim 10, wherein the iridium compound is fac-tris(2-phenylpyridine) iridium, as denoted by the formula:

13. The organic light emitting device of claim 10, wherein the iridium compound is denoted by the formula:

wherein R is an alkyl or aryl group.

14. The organic light emitting device of claim 13, wherein the R group is an alkyl group.

15. The organic light emitting device of claim 13, wherein the R group is an aryl group.

16. The organic light emitting device of claim 9, wherein the phosphorescent organometallic compound is a cyclometallated osmium compound.

17. The organic light emitting device of claim 9, wherein the phosphorescent organometallic compound is a platinum compound.

18. The organic light emitting device of claim 9, wherein the phosphorescent organometallic compound is a cyclometallated compound including a cycle closed with at least one metal-X bond, wherein X is selected from the group consisting of nitrogen, sulfur, phosphorous, arsenic and oxygen, and including a cycle closed with at least one carbon-metal bond.

19. The organic light emitting device of claim 18, wherein the phosphorescent organometallic compound is a cyclometallated platinum compound.

20. The organic light emitting device of claim 18, wherein X is nitrogen.

21. The organic light emitting device of claim 9, wherein the host material is a polymeric host material.

22. The organic light emitting device of claim 21, wherein the polymeric host material is a polyvinylcarbazole.

23. The organic light emitting device of claim 9, wherein the phosphorescent organometallic compound is substituted with an electron donor group.

24. The organic light emitting device of claim 9, wherein the phosphorescent organometallic compound is substituted with an electron acceptor group.

25. An organic light emitting device comprising an anode, a cathode and an emissive layer, wherein the emissive layer is located between the anode and the cathode and the emissive layer comprises a phosphorescent organometallic compound, wherein the phosphorescent organometallic compound is a cyclometallated compound including a cyclometallated ring having a carbon-metal bond.

26. The organic light emitting device of claim 25, wherein the cyclometallated compound is a platinum compound.

27. The organic light emitting device of claim 25, wherein the cyclometallated compound further includes a cycle closed with at least one metal-X bond, wherein X is selected from the group consisting of nitrogen, sulfur, phosphorous, arsenic and oxygen.

28. The organic light emitting device of claim 27, wherein the cyclometallated compound is a platinum compound.

29. The organic light emitting device of claim 27, wherein X is nitrogen.