Organic light emitting devices

• US 9,871,219 B2
• Filed: 03/30/2017
• Issued: 01/16/2018
• 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:
  US15/474,184
• Publication Number:
  US 20170207408A1
• Time in Patent Office: 292 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:

a cathode;

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; and

an anode;

wherein, the spacer layer is between the first emissive layer and the second emissive layer, the spacer layer inhibits quenching of the triplet excitons in the second emissive layer;

an interface between the spacer layer and one of the first and second emissive layers forming a heterojunction; and

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 second emissive layer comprises a phosphorescent green emitting material and a phosphorescent red emitting material;

(b) the second emissive layer comprises a phosphorescent green emitting material and the organic light emitting device further comprises a third emissive layer comprising a phosphorescent red emitting material;

or

(c) the first emissive layer further comprising a fluorescent green emitting material; and

the second emissive layer comprising a phosphorescent red emitting material; and

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 device further comprises a separate non-emitting hole transporting layer.

3. 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.

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

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

6. The organic light emitting device of claim 1, wherein the host material of the first emissive layer and the host material of the second emissive layer are different chemical compounds.

7. The organic light emitting device of claim 6, wherein the material of the spacer layer is different than the host material of the first emissive layer.

8. The organic light emitting device of claim 6, wherein the spacer layer is comprised of the host material of the second emissive layer.

9. An organic light emitting device comprising in order:

a cathode;

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; and

an anode;

wherein the spacer layer inhibits quenching of the triplet excitons in the second emissive layer;

an interface between the spacer layer and one of the first and second emissive layers forming a heterojunction; and

the spacer layer comprises a material that has a triplet energy that is higher than the triplet energy of the phosphorescent emitting material; and

wherein one of the following is true;

(a) the second emissive layer comprises a phosphorescent green emitting material and a phosphorescent red emitting material;

(b) the second emissive layer comprises a phosphorescent green emitting material and the organic light emitting device further comprises a third emissive layer comprising a phosphorescent red emitting material;

or

(c) the first emissive layer further comprises a fluorescent green emitting material; and

the second emissive layer comprising a phosphorescent red emitting material; and

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

10. The organic light emitting device of claim 9, wherein a combined emission of the emitting materials gives a white emission from the device.

11. The organic light emitting device of claim 9, wherein the host material of the first emissive layer and the host material of the second emissive layer are different chemical compounds.

12. A consumer product comprising 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 spacer layer;

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

an anode;

wherein, the spacer layer is between the first emissive layer and the second emissive layer, the spacer layer inhibits quenching of the triplet excitons in the second emissive layer;

an interface between the spacer layer and one of the first and second emissive layers forming a heterojunction; and

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 second emissive layer comprises a phosphorescent green emitting material and a phosphorescent red emitting material;

(b) the second emissive layer comprises a phosphorescent green emitting material and the organic light emitting device further comprises a third emissive layer comprising a phosphorescent red emitting material;

or

(c) the first emissive layer further comprising a fluorescent green emitting material; and

the second emissive layer comprising a phosphorescent red emitting material; and

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

13. The consumer product of claim 12, wherein the consumer product is selected from the group consisting of flat panel displays, computer monitors, televisions, billboards, lights for interior or exterior illumination and/or signaling, heads-up displays, fully transparent displays, flexible displays, laser printers, telephones, cell phones, personal digital assistants (PDAs), laptop computers, digital cameras, camcorders, viewfinders, micro-displays, vehicles, a large area wall, theater or stadium screen, or a sign.