Efficiency transparent cathode

• US 20040032206A1
• Filed: 08/16/2002
• Published: 02/19/2004
• Est. Priority Date: 08/16/2002
• Status: Active Grant

• Current Assignee: Universal Display Corporation
• Original Assignee: Universal Display Corporation
• Inventors: Weaver, Michael S., Lu, Min-Hao Michael, Zhou, Theodore
• Granted Patent: US 7,061,175 B2
• Time in Patent Office: Days
• US Class Current: 313/504
• CPC Class Codes: H05B 33/28 of translucent electrodes
• CPC Class Codes: H10K 2102/3031 Two-side emission, e.g. transparent OLEDs [TOLED]
• CPC Class Codes: H10K 50/171 Electron injection layers

Abstract

An organic light emitting device is provided. The device includes an anode, an organic layer disposed over the anode, a layer comprising an alkaline metal compound disposed over the organic layer, a layer comprising Mg or a Mg-metal alloy disposed over the layer comprising an alkaline metal compound, and a layer comprising a transparent conductive metal oxide disposed over the layer comprising Mg or Mg-metal alloy. A method of fabricating an organic light emitting device is also provided. An organic layer is deposited over an anode. An electron injection enhancement layer consisting essentially of an alkaline metal compound is deposited over the organic layer. A transparent cathode, including a layer of Mg or Mg-metal alloy and a layer of metal oxide, is deposited over the layer of alkaline metal compound. A device fabricated by this process is also provided.

Claims

1. An organic light emitting device, comprising:

(a) an anode;

(b) an organic layer disposed over the anode;

(c) a layer comprising an alkaline metal compound disposed over the organic layer;

(d) a layer comprising Mg or a Mg-metal alloy disposed over the layer comprising an alkaline metal compound, and

(e) a layer comprising a transparent conductive metal oxide disposed over the layer comprising Mg or Mg-metal alloy.

2. The device of claim 1, wherein the layer comprising an alkaline metal compound consists essentially of an alkaline halide.

3. The device of claim 1, wherein the layer comprising Mg or a Mg-metal alloy consists essentially of Mg or a Mg metal alloy.

4. The device of claim 1, wherein the layer comprising Mg or a Mg-metal alloy consists essentially of Mg:

Ag.

5. The device of claim 1, wherein the layer comprising a transparent conductive metal oxide consists essentially of indium tin oxide.

6. The device of claim 1, wherein the layer comprising a transparent conductive metal oxide consists essentially of indium zinc oxide.

7. The device of claim 1, wherein:

the layer comprising an alkaline metal compound consists essentially of an alkaline metal compound;

the layer comprising Mg or Mg-metal alloy consists essentially of Mg;

Ag; and

the layer comprising a metal oxide consists essentially of indium tin oxide.

8. The device of claim 1, wherein the layer comprising alkaline metal compound comprises LiF.

9. The device of claim 1, wherein the layer comprising alkaline metal compound consists essentially of LiF.

10. The device of claim 1, wherein the layer comprising alkaline metal compound comprises LiO.

11. The device of claim 1, wherein the layer comprising alkaline metal compound consists essentially of LiO.

12. The device of claim 1, wherein the layer comprising an alkaline metal compound has a thickness of about 0.3 to 5 nm.

13. The device of claim 1, wherein the layer comprising an alkaline metal compound has a thickness of about 0.5 to 1 nm.

14. The device of claim 1, wherein the organic layer further comprises a layer consisting essentially of CuPc, a layer consisting essentially of NPD, a light emitting layer, a layer consisting essentially of BAlq, and a layer consisting essentially of Alq3, disposed in that order over the anode.

15. The device of claim 1, wherein the device is incorporated into an active matrix display.

16. An organic light emitting device, comprising:

(a) an anode;

(b) an organic layer disposed over and electrically connected to the anode;

(c) a transparent cathode disposed over and electrically connected to the organic layer; and

(d) an electron injection enhancement layer comprising an alkaline metal compound disposed between and electrically connected to the organic layer and the transparent cathode.

17. An organic light emitting device, comprising:

(a) an anode;

(b) an organic layer adapted to emit light disposed over the anode;

(c) a transparent cathode disposed over the layer of alkaline metal compound.

(d) means for enhancing the injection of electrons from the cathode into the organic layer.

18. The device of claim 17, wherein the means for enhancing the injection of electrons includes LiF.

19. A device fabricated by the process of:

(a) depositing an organic material over an anode;

(b) depositing an alkaline metal compound over the organic material;

(c) depositing Mg or a Mg-metal alloy over the alkaline metal compound; and

(e) depositing a metal oxide over the Mg or Mg-metal alloy.

20. The device of claim 19, wherein the alkaline metal compound if LiF.

21. The device of claim 19, wherein the Mg or Mg-metal alloy is Mg:

Ag.

22. The device of claim 19, wherein the metal oxide is indium tin oxide.

23. The device of claim 19, wherein the metal oxide is deposited by sputtering.

24. The device of claim 19, wherein the metal oxide is deposited by thermal vapor phase deposition.

25. A method of fabricating an organic light emitting device, comprising:

(a) depositing an organic layer over an anode;

(b) depositing an electron injection enhancement layer consisting essentially of an alkaline metal compound over the organic layer; and

(c) depositing a transparent cathode, including a layer of Mg or Mg-metal alloy and a layer of metal oxide, over the layer of alkaline metal compound.

26. The method of claim 25, wherein the electron injection enhancement layer is deposited by thermal deposition.

27. The method of claim 25, wherein the electron injection enhancement layer includes LiF.

28. The method of claim 25, wherein the metal oxide layer is deposited by sputtering.

29. The method of claim 25, wherein the metal oxide layer is deposited by thermal vapor phase deposition.

30. An organic light emitting device, comprising:

(a) an anode;

(b) an organic layer disposed over the anode;

(c) a layer comprising Mg or a Mg-metal alloy disposed over the organic layer, and

(d) a layer comprising a transparent conductive metal oxide disposed over the layer comprising Mg or Mg-metal alloy;

wherein the organic layer includes an alkaline metal dopant, and the layer comprising Mg or Mg-metal alloy includes fluorine or oxygen as a dopant.