Fluorescent filtered electrophosphorescence

• US 20060273714A1
• Filed: 06/01/2005
• Published: 12/07/2006
• Est. Priority Date: 06/01/2005
• Status: Active Grant

• Current Assignee: The Trustees of Princeton University (Princeton University), University of Southern California
• Original Assignee: Entire Interest
• Inventors: Forrest, Stephen R., Thompson, Mark E., Giebink, Noel, Sun, Yiru
• Granted Patent: US 7,474,048 B2
• Time in Patent Office: Days
• US Class Current: 313/504
• CPC Class Codes: H10K 2101/10 Triplet emission
• CPC Class Codes: H10K 2101/27 Combination of fluorescent and phosphorescent 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 50/131 with spacer layers between the electroluminescent layers
• CPC Class Codes: H10K 85/324 comprising aluminium, e.g. Alq3
• CPC Class Codes: H10K 85/342 comprising iridium
• CPC Class Codes: H10K 85/611 Charge transfer complexes
• 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 85/654 comprising only nitrogen as heteroatom H10K85/652 takes precedence
• CPC Class Codes: H10K 85/657 Polycyclic condensed heteroaromatic hydrocarbons

Abstract

The present invention relates to organic light emitting devices (OLEDs), and more specifically to OLEDS that emit light using a combination of fluorescent emitters and phosphorescent emitters for the efficient utilization of all of the electrically generated excitons.

Claims

1. An organic light emitting device comprising:

a cathode,

an emissive region, and

an anode

wherein,

the emissive region comprises a fluorescent layer comprising a fluorescent emitting material as a dopant in a host material, and a phosphorescent layer comprising a phosphorescent emitting material as a dopant in a host material;

and wherein greater than about 50% of the excitons are generated in the fluorescent layer.

2. The device of claim 1, wherein greater than about 70% of the excitons are generated in the fluorescent layer.

3. The device of claim 1, wherein the emissive region further comprises a spacer layer between the fluorescent layer and the phosphorescent layer.

4. The device of claim 3, wherein the host material for the fluorescent layer, the host material for the phosphorescent layer and the spacer layer are comprised of the same material.

5. The device of claim 1, wherein the fluorescent emitting material is a blue emitting fluorescent material.

6. The device of claim 1, wherein the emissive region has the structure fluorescent layer/spacer/phosphorescent layer.

7. The device of claim 1, wherein the emissive region has the structure fluorescent layer/spacer/phosphorescent layer/phosphorescent layer.

8. The device of claim 1, wherein the emissive region has the structure fluorescent layer/spacer/phosphorescent layer/fluorescent layer.

9. The device of claim 1, wherein the emissive region has the structure fluorescent layer/phosphorescent layer/spacer/fluorescent layer.

10. The device of claim 1, wherein the emissive region has the structure fluorescent layer/spacer/phosphorescent layer/spacer/fluorescent layer.

11. The device of claim 1, wherein the emissive region has the structure fluorescent layer/spacer/phosphorescent layer/phosphorescent layer/fluorescent layer.

12. The device of claim 1, wherein the emissive region has the structure fluorescent layer/phosphorescent layer/phosphorescent layer/spacer/fluorescent layer.

13. The device of claim 1, wherein the emissive region has the structure fluorescent layer/spacer/phosphorescent layer/phosphorescent layer/spacer/fluorescent layer.

14. The organic light emitting device of claim 1, wherein the device emits light having CIE coordinates of X=0.37±

0.07, and Y=0.37±

0.07.

15. The organic light emitting device of claim 1, wherein the device emits light having CIE coordinates of X=0.35±

0.05, and Y=0.35±

0.05.

16. The organic light emitting device of claim 1, wherein the device emits light having CIE coordinates of X=0.33±

0.02, Y=0.33±

0.02.

17. An organic light emitting device comprising:

a cathode,

an emissive region comprising the following layers in sequence

a fluorescent layer comprising a fluorescent emitting material as a dopant in a host material,

a spacer layer,

a phosphorescent layer comprising a phosphorescent emitting material as a dopant in a host material,

a spacer layer, and

a fluorescent layer comprising a fluorescent emitting material as a dopant in a host material; and

an anode.

18. The device of claim 17, wherein greater than about 50% of the excitons are generated in the fluorescent layers.

19. The device of claim 18, wherein greater than about 70% of the excitons are generated in the fluorescent layers.

20. The device of claim 17, wherein the fluorescent material is a blue-emitting material.

21. The device of claim 20, wherein the phosphorescent layer comprises a green phosphorescent emitting material and a red phosphorescent emitting material.

22. The device of claim 17, wherein the host material for the fluorescent layers, the host material for the phosphorescent layer and the spacer layers are comprised of the same material.

23. The organic light emitting device of claim 17, wherein the device emits light having CIE coordinates of X=0.37±

0.07, and Y=0.37±

0.07.

24. The organic light emitting device of claim 17, wherein the device emits light having CIE coordinates of X=0.35±

0.05, and Y=0.35±

0.05.

25. The organic light emitting device of claim 17, wherein the device emits light having CIE coordinates of X=0.33±

0.02, Y=0.33±

0.02.