Organic light emitting devices

• US 9,647,227 B2
• Filed: 05/29/2015
• Issued: 05/09/2017
• 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., Hack, Michael, Esler, James R.
• Primary Examiner(s): Bohaty, Andrew K
• Application Number:
  US14/725,065
• Publication Number:
  US 20150303395A1
• Time in Patent Office: 711 Days
• Field of Search: 428690, 428691, 428917, 4284114, 428336, 427 58, 427 66, 313500-512, 257 40, 257 88-104, 257E51001-E51052, 25230116-30135
• 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 an emissive region in 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 emissive region may further comprise additional fluorescent or phosphorescent emissive materials. Preferably, the emissive region has three different emissive materials—a red emissive material, a green emissive material and a blue emissive material. Organic light emitting devices incorporating the emissive region 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 an emissive region, wherein the emissive region comprises:

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

a spacer layer;

a second emissive layer comprising a phosphorescent emitting material as a dopant in a host material, wherein the spacer layer is between the first emissive layer and the second emissive layer, wherein the spacer layer inhibits quenching of the triplet excitons in the second emissive layer, wherein an interface between the spacer layer and one of the first and second emissive layers forming a heterojunction, and wherein the spacer layer comprises a material that has a triplet energy that is higher than the triplet energy of the phosphorescent emitting material,

wherein one of the following is true;

(a) the phosphorescent emitting material in the second emissive layer is a phosphorescent green emitting material and the second emissive layer further comprises a phosphorescent red emitting material as a second dopant;

(b) the phosphorescent emitting material in the second emissive layer is a phosphorescent green emitting material and the emissive region further comprises a third emissive layer on the same side of the spacer layer as the second emissive layer, wherein the third emissive layer comprises a phosphorescent red emitting material as a dopant in a host material;

or

(c) the phosphorescent emitting material in the second emissive layer is a phosphorescent red emitting material and the first emissive layer further comprises a fluorescent green emitting material as a second dopant.

2. The organic light emitting device of claim 1, wherein a combined emission of the emitting materials provides a white emission from the device.

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

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

5. 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.

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

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

8. The organic light emitting device of claim 1, wherein only (a) is true.

9. The organic light emitting device of claim 1, wherein only (b) is true.

10. The organic light emitting device of claim 1, wherein only (c) is true.

11. An emissive region in an organic light emitting device, the emissive region comprising in order:

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

a spacer layer; and

a second emissive layer comprising a phosphorescent emitting material as a dopant in a host material, wherein the spacer layer inhibits quenching of the triplet excitons in the second emissive layer,

wherein an interface between the spacer layer and one of the first and second emissive layers forms a heterojunction, and the spacer layer comprises a material that has a triplet energy that is higher than the triplet energy of the phosphorecent emitting material,

wherein one of the following is true;

(a) the phosphorescent emitting material in the second emissive layer is a phosphorescent green emitting material and the second emissive layer further comprises a phosphorescent red emitting material as a second dopant;

(b) the phosphorescent emitting material in the second emissive layer is a phosphorescent green emitting material and the emissive region further comprises a third emissive layer on the same side of the spacer layer as the second emissive layer, wherein the third emissive layer comprises a phosphorescent red emitting material as a dopant in a host material;

or

(c) the phosphorescent emitting material in the second emissive layer is a phosphorescent red emitting material and the first emissive layer further comprises a fluorescent green emitting material as a second dopant.

12. The emissive region of claim 11, wherein the fluorescent emitting material is a blue emitting material.

13. The emissive region of claim 11, wherein a combined emission of the emitting materials gives a white emission from the device.

14. The emissive region of claim 13, wherein the device emits light having CIE coordinates of X=0.37±

0.07, and Y=0.37±

0.07.

15. The emissive region of claim 11, wherein the device has a maximum external quantum efficiency of at least about 5.0%.

16. The emissive region of claim 11, wherein the device has a maximum external quantum efficiency of at least about 6.0%.

17. The emissive region of claim 11, wherein only (a) is true.

18. The emissive region of claim 11, wherein only (b) is true.

19. The emissive region of claim 11, wherein only (c) is true.