High efficiency multi-color electro-phosphorescent OLEDs

• US 7,285,907 B2
• Filed: 08/24/2005
• Issued: 10/23/2007
• Est. Priority Date: 05/16/2001
• 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: Forrest, Stephen R., Thompson, Mark E., D'Andrade, Brian
• Primary Examiner(s): Santiago; Mariceli
• Application Number:
  US11/211,385
• Publication Number:
  US 20050282036A1
• Time in Patent Office: 790 Days
• Field of Search: 313/503, 313/504, 313/506
• US Class Current: 313/504
• CPC Class Codes: C09K 11/06 containing organic luminescent materials
• CPC Class Codes: C09K 2211/1029 containing one nitrogen atom as the heteroatom
• 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: 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 50/157 between the light-emitting layer and the cathode
• CPC Class Codes: H10K 50/17 Carrier injection layers
• CPC Class Codes: H10K 50/18 Carrier blocking layers
• CPC Class Codes: Y10S 428/917 Electroluminescent
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree

Abstract

The present invention relates to efficient organic light emitting devices (OLEDs) doped with multiple light-emitting dopants, at least one dopant comprising a phosphorescent emitter, in a thin film emissive layer or layers. The present invention is directed to an efficient phosphorescent organic light emitting device utilizing a plurality of emissive dopants in an emissive region, wherein at least one of the dopants is a phosphorescent material. Thus, the present invention provides an organic light emitting device comprising an emissive region, wherein the emissive region comprises a host material, and a plurality of emissive dopants, wherein the emissive region is comprised of a plurality of bands and each emissive dopant is doped into a separate band within the emissive region, and wherein at least one of the emissive dopants emits light by phosphorescence.

Claims

1. An organic light emitting device, comprising:

an anode, a cathode, and an emissive region;

wherein

the emissive region is located between the anode and the cathode, and comprises a host material, a plurality of emissive dopants, and a plurality of bands;

wherein

each emissive dopant is doped into a separate band within the emissive region; and

the host material in at least a portion of the bands is different from one band to the next;

wherein

at least one of the emissive dopants emits light by phosphorescence from a triplet molecular excited state; and

wherein

a combined emission of the plurality of emissive dopants sufficiently spans the visible spectrum to give a white emission.

2. The device of claim 1, wherein the combined emission has a color rendering index of at least about 70.

3. The device of claim 2, wherein the combined emission has a color rendering index of at least about 80.

4. The device of claim 1, wherein more than one emissive dopant emits by phosphorescence.

5. The device of claim 1, wherein each emissive dopant emits by phosphorescence.

6. The device of claim 1, wherein at least one of the emissive dopants is an organometallic compound.

7. An organic light emitting device, comprising:

an anode, a cathode, and an emissive region;

wherein

the emissive region is located between the anode and the cathode, and comprises a host material, a plurality of emissive dopants, a host layer doped with at least one phosphorescent dopant, and a separate host layer doped with a fluorescent dopant;

wherein

the at least one phosphorescent dopant emits light by phosphorescence from a triplet molecular excited state; and

a combined emission of the plurality of emissive dopants sufficiently spans the visible spectrum to give a white emission.

8. The device of claim 7, wherein the combined emission has a color rendering index of at least about 70.

9. The device of claim 8, wherein the combined emission has a color rendering index of at least about 80.

10. The device of claim 7, wherein more than one emissive dopant emits by phosphorescence.

11. The device of claim 7, wherein at least one phosphorescent dopant is an organometallic compound.

12. The device of claim 7, wherein each phosphorescent dopant is an organometallic compound.

13. An organic light emitting device, comprising:

an anode, a cathode, and an emissive region;

wherein

the emissive region is located between the anode and the cathode, and comprises;

a host material and a plurality of emissive dopants;

wherein

the plurality of emissive dopants comprise a first phosphorescent dopant and a second phosphorescent dopant;

the first and second phosphorescent dopants emit light by phosphorescence from a triplet molecular excited state; and

a combined emission of the plurality of emissive dopants sufficiently spans the visible spectrum to give a white emission.

14. The device of claim 13, wherein the second doped region is contained in its entirety within the first doped region.

15. The device of claim 13, wherein the combined emission has a color rendering index of at least about 70.

16. The device of claim 15, wherein the combined emission has a color rendering index of at least about 80.

17. The device of claim 13, wherein at least one phosphorescent dopant is an organometallic compound.

18. The device of claim 13, wherein each phosphorescent dopant is an organometallic compound.

19. The device of claim 13, wherein a first doped region of the first phosphorescent dopant overlaps a second doped region of the second phosphorescent dopant.