Hybrid OLED having phosphorescent and fluorescent emitters

• US 20060232194A1
• Filed: 04/13/2005
• Published: 10/19/2006
• Est. Priority Date: 04/13/2005
• Status: Active Grant

• Current Assignee: Universal Display Corporation
• Original Assignee: Universal Display Corporation
• Inventors: Tung, Yeh-Jiun, Weaver, Michael S., Esler, James, Hack, Michael
• Granted Patent: US 9,070,884 B2
• Time in Patent Office: Days
• US Class Current: 313/504
• CPC Class Codes: C09K 11/06 containing organic luminescent materials
• CPC Class Codes: C09K 2211/1011 Condensed systems
• 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 2101/27 Combination of fluorescent and phosphorescent emission
• CPC Class Codes: H10K 2101/30 Highest occupied molecular orbital [HOMO], lowest unoccupied molecular orbital [LUMO] or Fermi energy values
• CPC Class Codes: H10K 2101/40 Interrelation of parameters between multiple constituent active layers or sublayers, e.g. HOMO values in adjacent layers
• CPC Class Codes: H10K 2102/351 Thickness
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 50/13 comprising stacked EL layers within one EL unit
• CPC Class Codes: H10K 50/131 with spacer layers between the electroluminescent layers
• CPC Class Codes: H10K 50/15 Hole transporting layers
• CPC Class Codes: H10K 50/19 Tandem OLEDs
• CPC Class Codes: H10K 59/32 Stacked devices having two or more layers, each emitting at different wavelengths
• CPC Class Codes: H10K 85/324 comprising aluminium, e.g. Alq3
• CPC Class Codes: H10K 85/342 comprising iridium
• CPC Class Codes: H10K 85/615 Polycyclic condensed aromatic hydrocarbons, e.g. anthracene
• CPC Class Codes: H10K 85/622 containing four rings, e.g. pyrene
• CPC Class Codes: H10K 85/626 containing more than one polycyclic condensed aromatic rings, e.g. bis-anthracene
• 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: H10K 85/6572 : comprising only nitrogen in the heteroaromatic polycondensed ring system, e.g. phenanthroline or carbazole

Abstract

The present invention provides organic light emitting devices having a combined emission from at least two emissive materials, a fluorescent blue emissive material and a phosphorescent emissive material. The device may further comprise additional fluorescent or phosphorescent emissive materials. In preferred embodiments, the invention provides OLEDs having three different emissive materials—a red emissive material, a green emissive material and a blue emissive material. The invention provides a device architecture which is optimized for efficiency and lifetime by using a combination of fluorescent and phosphorescent emitters. Further, in preferred embodiments the device architecture provides a high color-stability of the light emission over a wide range of currents or luminances.

Claims

1. An organic light emitting device comprising:

a cathode

a first emissive layer comprising a fluorescent blue emitting material as a dopant in a host material;

a second emissive layer comprising a phosphorescent emitting material as a dopant in a host material; and

an anode

wherein, a combined emission of the emitting materials gives a white emission from the device.

2. The organic light emitting device of claim 1, wherein the blue emitting material is a blue emitting arylpyrene.

3. The organic light emitting device of claim 1, wherein the blue emitting material is 1,3,6,8-tetra(2-naphthyl)pyrene.

4. The organic light emitting device of claim 1, wherein the blue emitting material is a blue emitting arylenevinylene compound.

5. The organic light emitting device of claim 1, wherein the device further comprises a separate non-emitting hole transporting layer.

6. The organic light emitting device of claim 1, wherein the device further comprises a spacer layer between the first emissive layer and the second emissive layer.

7. The organic light emitting device of claim 1, wherein the second emissive layer comprises a phosphorescent green emitting material and a phosphorescent red emitting material.

8. The organic light emitting device of claim 1, wherein the emissive region comprises:

a first emissive layer comprising the fluorescent blue emitting material;

a second emissive layer comprising a phosphorescent green emitting material; and

a third emissive layer comprising a phosphorescent red emitting material.

9. The organic light emitting device of claim 1, wherein the emissive region comprises:

a first emissive layer comprising the fluorescent blue emitting material and a fluorescent green emitting material; and

a second emissive layer comprising a phosphorescent red emitting material.

10. 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.

11. The organic light emitting device of claim 1, wherein the device has a maximum external quantum efficiency of at least about 5.0%.

12. The organic light emitting device of claim 1, wherein the device has a maximum external quantum efficiency of at least about 6.0%.

13. An organic light emitting device comprising in order:

a cathode

a first emissive layer comprising a fluorescent emitting material;

a second emissive layer comprising a phosphorescent emitting material; and

an anode

wherein, when a voltage is applied across the device light is emitted from the emitting materials.

14. The organic light emitting device of claim 13, wherein the first emissive layer comprises a host material and the fluorescent emitting material as a dopant in the host material.

15. The organic light emitting device of claim 14, wherein the fluorescent emitting material is a blue emitting material.

16. The organic light emitting device of claim 15, wherein the fluorescent emitting material is a blue emitting arylpyrene.

17. The organic light emitting device of claim 16, wherein the blue emitting material is 1,3,6,8-tetra(2-naphthyl)pyrene.

18. The organic light emitting device of claim 13, wherein the blue emitting material is a blue emitting arylenevinylene compound.

19. The organic light emitting device of claim 13, wherein the device further comprises a spacer layer between the first emissive layer and the second emissive layer.

20. The organic light emitting device of claim 13, wherein the second emissive layer comprises a phosphorescent green emitting material and a phosphorescent red emitting material.

21. The organic light emitting device of claim 13, wherein the emissive region comprises:

a first emissive layer comprising the fluorescent blue emitting material;

a second emissive layer comprising a phosphorescent green emitting material; and

a third emissive layer comprising a phosphorescent red emitting material.

22. The organic light emitting device of claim 13, wherein the emissive region comprises:

a first emissive layer comprising the fluorescent blue emitting material and a fluorescent green emitting material; and

a second emissive layer comprising a phosphorescent red emitting material.

23. The organic light emitting device of claim 13, wherein a combined emission of the emitting materials gives a white emission from the device.

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

0.07, and Y=0.37±

0.07.

25. The organic light emitting device of claim 13, wherein the device has a maximum external quantum efficiency of at least about 5.0%.

26. The organic light emitting device of claim 13, wherein the device has a maximum external quantum efficiency of at least about 6.0%.