Electroluminescent devices and cathodes

• US 20040075382A1
• Filed: 10/22/2002
• Published: 04/22/2004
• Est. Priority Date: 10/22/2002
• Status: Active Grant

• Current Assignee: Pictiva Displays International Limited (f/k/a Dolya Holdco 5 Limited) (Key Patent Innovations Limited)
• Original Assignee: Osram Opto Semiconductors GmbH (Ams-Osram AG)
• Inventors: Cumpston, Brian H., Stegamat, Reza
• Granted Patent: US 7,015,639 B2
• Time in Patent Office: Days
• US Class Current: 313/506
• CPC Class Codes: H05B 33/10 Apparatus or processes specially adapted to the manufacture of electroluminescent light sources
• CPC Class Codes: H05B 33/28 of translucent electrodes
• CPC Class Codes: H10K 2102/3026 Top emission
• CPC Class Codes: H10K 50/828 Transparent cathodes, e.g. comprising thin metal layers
• CPC Class Codes: H10K 50/86 Arrangements for improving contrast, e.g. preventing reflection of ambient light
• CPC Class Codes: H10K 59/32 Stacked devices having two or more layers, each emitting at different wavelengths

Abstract

An embodiment of the present invention pertains to an electrode that is substantially transparent and conductive and that is incorporated within an organic electronic device. This electrode includes a first layer and a second layer that is on the first layer. The electrode optionally includes a third layer on the second layer. The first layer, the second layer, and the third layer are exposed to a medium and reactions between various combinations of the first layer, the second layer, the third layer, and the medium produce the substantially transparent and conductive electrode.

Claims

1. A substantially transparent and conductive electrode, comprising:

a first layer; and

a second layer on the first layer,

wherein the first layer and the second layer are exposed to a medium and the second layer reacts with at least one of;

(1) the first layer and (2) the medium to produce the substantially transparent and conductive electrode.

2. The electrode of claim 1 wherein the first layer is comprised of an electron injecting material.

3. The electrode of claim 1 wherein the first layer is comprised of a low work function metal.

4. The electrode of claim 1 wherein the second layer is comprised of a conductive material.

5. The electrode of claim 1 wherein the medium is at least one of a gas and a liquid.

6. The electrode of claim 1 wherein the medium is comprised of at least one of argon, nitrogen, oxygen, moisture, residual solvent, and a mixture thereof.

7. The electrode of claim 1 further comprising a barrier layer between the first layer and the second layer.

8. The electrode of claim 7 wherein the barrier layer minimizes the reaction between the first layer and the second layer.

10. The electrode of claim 1 wherein its transparency is greater than sixty percent.

13. The electrode of claim 1 wherein the electrode is a top electrode and is incorporated in an organic light emitting device (“

OLED”

) that includes

a substrate;

a bottom electrode on the substrate; and

at least one organic layer on the bottom electrode,

wherein the top electrode is on the at least one organic layer.

14. The electrode of claim 13 further comprising a capping layer deposited on the top electrode.

15. The electrode of claim 14 wherein the capping layer is comprised of an electrically conductive layer.

16. The electrode of claim 14 wherein the capping layer is comprised of a conductive and transparent material.

17. The electrode of claim 1 incorporated in a top-emitting OLED.

18. The electrode of claim 1 incorporated in a top and bottom emitting OLED.

19. The electrode of claim 1 incorporated in each of a plurality of OLEDs of a stacked OLED device.

20. The electrode of claim 1 wherein the electrode is incorporated in an OLED that includes

a barrier layer on the electrode,

wherein the barrier layer includes a barrier material selected from the group consisting of molybdenum oxide, boron oxide, vanadium oxide, molybdenum carbide, vanadium carbide, an oxide of a molybdenum alloy, an oxide of a boron alloy, an oxide of a vanadium alloy, a composition comprising sodium, aluminum, and fluorine, and mixtures thereof.

21. The electrode of claim 1 wherein the electrode is incorporated in a substantially transparent OLED of an OLED display, and

wherein a low-reflectance absorber is on the electrode.

22. The electrode of claim 21 wherein the low-reflectance absorber is a black absorber, or a colored absorber that absorbs only part of a light-spectrum emitted from the substantially transparent OLED.

23. An organic electronic device comprising the electrode of claim 1.

24. The electrode of claim 1 incorporated in any one of an organic light emitting device, a solar cell, a phototransistor, a photodetector, a laser, or an opto-coupler.

9. The electrode of claim I further comprising a third layer on the second layer wherein the third layer is comprised of a reactive metal.

11. The electrode of claim 9 wherein

the first layer is comprised of a barium layer that has a thickness from about 0.5 nm to about 10 nm,

the second layer is comprised of a silver layer that has a thickness from about 5 nm to about 200 nm, and

the third layer is comprised of a barium layer that has a thickness from about 5 nm to about 200 nm.

12. The electrode of claim 9 wherein

the first layer is comprised of a barium layer that has a thickness from about 1 nm to about 4 nm,

the second layer is comprised of a silver layer that has a thickness from about 20 nm to about 30 nm, and

the third layer is comprised of a barium layer that has a thickness from about 20 nm to about 30 nm.

25. A substantially transparent and conductive electrode, comprising:

a first layer;

a second layer on the first layer; and

a third layer on the second layer,

wherein the first layer, the second layer, and the third layer are exposed to a medium and wherein to produce the substantially transparent and conductive electrode any one of;

(1) the second layer reacts with the third layer or (2) the second layer reacts with the medium and the third layer reacts with the medium.

26. The electrode of claim 25 wherein the first layer, the second layer, and the third layer react together to produce the substantially transparent and conductive electrode.

27. The electrode of claim 25 wherein the first layer, the second layer, the third layer, and the medium react together to produce the substantially transparent and conductive electrode.

28. The electrode of claim 25 further comprising a barrier layer between the first layer and the second layer.

29. The electrode of claim 28 wherein the barrier layer minimizes the reaction between the first layer and at least one of:

(1) the second layer and (2) the third layer.

30. The electrode of claim 25 wherein

the first layer is comprised of an electron injecting material that has a thickness from about 1 nm to about 4 nm,

the second layer is comprised of a conductive material that has a thickness from about 20 nm to about 30 nm, and

the third layer is comprised of a reactive metal that has a thickness from about 20 nm to about 30 nm.

31. The electrode of claim 25 further comprising a capping layer deposited on the electrode.

32. The electrode of claim 31 wherein the capping layer is comprised of a conductive and transparent material.

33. The electrode of claim 25 wherein the electrode is incorporated in a substantially transparent OLED of an OLED display, and

wherein a low-reflectance absorber is on the electrode.

34. An organic electronic device comprising the electrode of claim 25.

35. A method to produce a substantially transparent and conductive electrode, comprising:

depositing a first layer; and

depositing a second layer on the first layer,

wherein the first layer and the second layer are exposed to a medium and the second layer reacts with at least one of;

(1) the first layer, and (2) the medium to produce the substantially transparent and conductive electrode.

36. The method of claim 35 further comprising

upon depositing the first layer, depositing a barrier layer on the first layer.

37. The method of claim 35 further comprising

upon depositing the second layer, depositing a third layer on the second layer.

38. The method of claim 35 wherein

the first layer is comprised of a barium layer that has a thickness from about 1 nm to about 4 nm thick;

the second layer is comprised of a silver layer that has a thickness from about 20 nm to about 30 nm; and

the medium is comprised of at least one of argon, nitrogen, oxygen, moisture, residual solvent, and a mixture thereof.