Organic light emitting devices

• US 20060251919A1
• Filed: 05/04/2005
• Published: 11/09/2006
• Est. Priority Date: 05/04/2005
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Hu, Nan-Xing, Aziz, Hany, Coggan, Jennifer A., Popovic, Zoran D.
• Granted Patent: US 8,487,527 B2
• Time in Patent Office: Days
• US Class Current: 428/690
• CPC Class Codes: H10K 2102/351 Thickness
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 85/654 comprising only nitrogen as heteroatom H10K85/652 takes precedence

Abstract

The present invention relates to organic light emitting devices (OLEDs) comprising an electroluminescent material layer comprising a mixture of at least two materials having different electron and hole transport capacities, and an electron transport layer comprising a triazine. Display devices comprising the OLEDs are also disclosed.

Claims

1. An organic light emitting device, comprising:

(a) an anode;

(b) a hole transport layer;

(c) an electroluminescent material layer comprising at least two materials having different electron and hole transport capacities;

(d) an electron transport layer comprising a triazine; and

(e) a cathode,

wherein said electroluminescent material layer has a thickness of less than 50 nm.

2. The device according to claim 1, wherein the triazine is present in the electron transport layer in an amount of at least about 50% by volume, relative to the total volume of the electron transport material.

3. The device according to claim 1, wherein said triazine is 4,4′

-bis[2-(4,6-diphenyl-1,3,5-triazinyl)]-1,1′

-biphenyl.

4. The device according to claim 1, wherein said triazine is doped with at least one of inorganic and organic materials.

5. The device according to claim 1, wherein at least one of the two materials having different electron and hole capacities is tris(8-hydroxyquinoline) aluminum.

6. The device according to claim 1, wherein one of the two materials having different electron and hole capacities is tris(8-hydroxyquinoline) aluminum and the other is selected from tertiary aromatic amines, anthracenes and tetracenes.

7. The device according to claim 6, wherein the tertiary aromatic amine is N,N′

-di(naphthalene-1-yl)-N,N′

-diphenyl-benzidine), the anthracene is 2-t-butyl-9,10-di-(2-naphthyl) anthracene, and the tetracene is rubrene

8. The device according to claim 1, wherein the electroluminescent material comprises an electron transport material and a hole transport material.

9. The device according to claim 1, wherein the electroluminescent material layer comprises an electron transport material and a bipolar transport material.

10. The device according to claim 1, wherein the electroluminescent material layer comprises a hole transport material and a bipolar transport material.

11. The device according to claim 1, wherein the electroluminescent material layer comprises at least one material capable of emitting light as a result of hole and electron recombination.

12. The device according to claim 11, wherein said material capable of emitting light is selected from fluorescent and phosphorescent materials.

13. The device according to claim 1, wherein said device is capable of operating at a driving voltage of less than 5V at a current density of at least 20 mA/cm².

14. The device according to claim 1, wherein said device has an operational stability characterized by a half life of at least 1000 hours at an initial brightness of at least 500 cd/m².

15. The device according to claim 1, wherein the thickness of the electroluminescent layer ranges from about 10 to less than about 50 nm.

16. The device according to claim 1, wherein the thickness of the electroluminescent layer ranges from about 10 to about 30 nm.

17. The device according to claim 1, wherein the device emits light having a wavelength of from about 400 nm to about 700 nm.

18. A display comprising at least one organic light emitting device comprising:

(a) an anode;

(b) a hole transport layer;

(c) an electroluminescent material layer comprising at least two materials having different electron and hole transport capacities;

(d) an electron transport layer comprising a triazine; and

(e) a cathode,

wherein said electroluminescent material layer has a thickness of less than 50 nm.

19. An organic light-emitting device comprising:

(a) an anode;

(b) a hole transport layer;

(c) an electroluminescent material layer comprising at least two of;

(i) an electron transport material,

(ii) a hole transport material, and

(iii) a bipolar transport material;

(d) an electron transport layer comprising a triazine; and

(e) a cathode,

wherein said electroluminescent material layer has a thickness of less than 50 nm.

20. The device according to claim 19, wherein two of (i), (ii), and (iii) are present in a ratio ranging from 5:

95 to 95;

5.