STABLE BLUE PHOSPHORESCENT ORGANIC LIGHT EMITTING DEVICES

• US 20090278444A1
• Filed: 10/24/2008
• Published: 11/12/2009
• Est. Priority Date: 11/09/2007
• Status: Active Grant

• Current Assignee: Board of Regents of the University of Michigan (University of Michigan), University of Southern California
• Original Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Inventors: Forrest, Stephen R., Thompson, Mark, Giebink, Noel
• Granted Patent: US 8,815,411 B2
• Time in Patent Office: Days
• US Class Current: 313/504
• CPC Class Codes: C07F 15/0033 Iridium compounds
• CPC Class Codes: C09K 11/06 containing organic luminescent materials
• CPC Class Codes: C09K 2211/1059 containing three nitrogen atoms as heteroatoms
• CPC Class Codes: C09K 2211/185 of the platinum group, i.e. Os, Ir, Pt, Ru, Rh or Pd
• CPC Class Codes: H10K 2101/10 Triplet emission
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 50/121 for assisting energy transfer, e.g. sensitization
• 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: Y10S 428/917 Electroluminescent

Abstract

Novel combination of materials and device architectures for organic light emitting devices is provided. An organic light emitting device, is provided, having an anode, a cathode, and an emissive layer disposed between the anode and the cathode. The emissive layer includes a host and a phosphorescent emissive dopant having a peak emissive wavelength less than 500 nm, and a radiative phosphorescent lifetime less than 1 microsecond. Preferably, the phosphorescent emissive dopant includes a ligand having a carbazole group.

Claims

1. An organic light emitting device, comprising:

an anode,

a cathode,

an emissive layer disposed between the anode and the cathode, the emissive layer further comprising a host and a phosphorescent emissive dopant having a peak emissive wavelength less than 500 nm, and a radiative phosphorescent lifetime less than 1 microsecond.

2. The device of claim 1, wherein the phosphorescent emissive dopant includes a carbazole group.

3. The device of claim 2, wherein the phosphorescent emissive dopant comprises a structure selected from the group consisting of:

where R₁-R₄ are independently selected from the group consisting of;

H, aryl and alkyl, where the aryl and alkyl may be further substituted,

Ar is an aryl that may be further substituted, and

M is a metal having an atomic weight greater than 40.

4. The device of claim 3, wherein M is iridium.

5. The device of claim 3, wherein additional ligands are coordinated to the metal M.

6. The device of claim 4, wherein three identical ligands are coordinated to the metal M.

7. The device of claim 1, wherein the device has a graded interface.

8. An organic light emitting device, comprising:

an anode,

a cathode,

an emissive layer disposed between the anode and the cathode, the emissive layer further comprising;

an phosphorescent emissive dopant including a steric bulky spacer group having a size of at least 10 angstroms.

9. The device of claim 8, wherein the phosphorescent emissive dopant has a peak emissive wavelength less than 500 nm.

10. The device of claim 8, wherein the steric bulky spacer group is selected from the group consisting of dendrimers and alkane chains.