Light emitting element, method for manufacturing same, and light emitting device

• US 8,921,838 B2
• Filed: 01/11/2013
• Issued: 12/30/2014
• Est. Priority Date: 08/06/2010
• Status: Active Grant

• Current Assignee: JDI Design and Development GK
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Takeuchi, Takayuki, Nishiyama, Seiji
• Primary Examiner(s): Such, Matthew W
• Assistant Examiner(s): Kilpatrick, Warren H
• Application Number:
  US13/739,384
• Publication Number:
  US 20130126842A1
• Time in Patent Office: 718 Days
• Field of Search: 257/40
• US Class Current: 257/40
• CPC Class Codes: H10K 50/17 Carrier injection layers
• CPC Class Codes: H10K 50/818 Reflective anodes, e.g. ITO combined with thick metallic layers
• CPC Class Codes: H10K 59/122 Pixel-defining structures or layers, e.g. banks
• CPC Class Codes: H10K 71/00 Manufacture or treatment specially adapted for the organic devices covered by this subclass

Abstract

Each of organic light-emitting elements 100a, 100b and 100c includes an anode, a functional layer including a hole-injection layer, a hole-transport layer and an organic light-emitting layer, and a cathode layered on a substrate in the stated order. Also, a bank defines a formation area of the organic light-emitting layer. Here, the hole-injection layer is a metal oxide layer formed by oxidizing an upper surface portion of the anode composed of the metal layer. Also, a portion of the hole-injection layer that is positioned under the area is depressed so as to form a recess, and upper peripheral edge of the recess is covered with a portion of the bank.

Claims

1. A light-emitter, comprising:

a first electrode;

a layered body disposed on the first electrode, the layered body including a charge injection layer, a charge transport layer, and a light-emitting layer;

a second electrode disposed on the layered body; and

a bank that defines a position of the light-emitting layer,

wherein the charge injection layer is formed by oxidation of an upper portion of a metal,

the first electrode includes a metal layer that is a lower portion of the metal,

an inner portion of the charge injection layer is depressed to define a recess,

an upper peripheral edge of the recess is covered with a part of the bank, the upper peripheral edge of the recess comprising at least a portion of a side surface of the recess, and

a lower surface of the charge transport layer faces a portion of the recess not covered with the part of the bank.

2. The light-emitter of claim 1, wherein the charge transport layer is in contact with the part of the bank covering the upper peripheral edge of the recess.

3. The light-emitter of claim 1, wherein the charge transport layer is surrounded by a portion of the recess in an area defined by the bank, and the part of the bank covering the upper peripheral edge of the recess.

4. The light-emitter of claim 1, wherein

the bank is formed by a solution, and

the solution is erosive to the charge injection layer formed by oxidation of the upper portion of the metal.

5. The light-emitter of claim 1, wherein

the part of the bank covering the upper peripheral edge of the recess is adjacent the recess, and

an inner side wall of the bank slopes upwardly with respect to a bottom surface of the recess.

6. The light-emitter of claim 1, wherein the part of the bank covering the upper peripheral edge of the recess is displaced from a bottom surface of the recess.

7. The light-emitter of claim 1, wherein the first electrode has one of a monolayer structure and a layer structure.

8. The light-emitter of claim 7, wherein the first electrode has the layer structure including the metal layer over a lower layer having a visible light reflectance of at least approximately 60%.

9. The light-emitter of claim 7, wherein

the first electrode has the layer structure including the metal layer over a lower layer,

the metal layer comprises at least one of molybdenum, chrome, vanadium, tungsten, nickel and iridium, and

the lower layer is an alloy that comprises at least one of aluminum and silver.

10. The light-emitter of claim 1, wherein the metal layer has a thickness of at most approximately 20 nm.

11. The light-emitter of claim 1, wherein the light-emitting layer is an organic EL layer.

12. The light-emitter of claim 1, wherein the charge injection layer protrudes along a base of the bank.

13. The light-emitter of claim 1, wherein the upper peripheral edge of the recess is defined by an angle formed between two surfaces, one of the two surfaces being a top surface of the charge injection layer in which the recess is not formed and the other of the two surfaces being the side surface of the recess.

14. A light-emitting device including a plurality of the light-emitter of claim 1.

15. A method for manufacturing a light-emitter including a first electrode;

a layered body that is over the first electrode and includes a charge injection layer, a charge transport layer, and a light-emitting layer, a second electrode over the layered body; and

a bank that defines a position of the light-emitting layer, the method comprising;

forming a metal layer;

forming a first metal oxide layer by oxidizing an upper portion of the metal layer;

forming a bank material layer on the first metal oxide layer;

removing a portion of the bank material layer and a portion of the first metal oxide layer to expose an exposed surface of an unoxidized portion of the metal layer and to define an area from which the portion of the bank material layer and the portion of the first metal oxide layer have been removed;

forming a second metal oxide layer by oxidizing an upper portion of the unoxidized portion of the metal layer around the exposed surface to form the charge injection layer, the charge injection layer including the second metal oxide layer and an unremoved portion of the first metal oxide layer, the first electrode including a portion of the metal layer that has not been oxidized;

thermally treating an unremoved portion of the bank material layer, the unremoved portion of the bank material layer being on the unremoved portion of the metal oxide layer;

forming the charge transport layer on the charge injection layer after thermally treating the unremoved portion of the bank material layer, and

forming the light-emitting layer on the charge transport layer,

wherein the charge injection layer comprises a material that is erosive by a solution used for removing the portion of the bank material layer,

an inner portion of the charge injection layer is eroded by the solution to define a recess having a bottom surface corresponding to the exposed surface so that the exposed surface is lower than a bottom surface of a portion of the unremoved portion of the bank material layer,

when thermally treating the unremoved portion of the bank material layer, the unremoved portion of the bank material layer is fluid so that the bank material layer extends to cover an upper peripheral edge of the recess, the upper peripheral edge of the recess comprising at least a portion of a side surface of the recess, and

the charge transport layer is formed on an exposed surface of the recess not covered with a part of the bank material layer.

16. The method for manufacturing the light-emitter of claim 15, wherein the first metal oxide layer and the second metal oxide layer are formed by one of natural oxidization by air exposure and oxidization in an oxidizing process.

17. The method for manufacturing the light-emitter of claim 15, wherein the first metal oxide layer and the second metal oxide layer are formed by natural oxidization by air expo sure.

18. The method for manufacturing the light-emitter of claim 15, wherein the first electrode has one of a monolayer structure and a layer structure.

19. The method for manufacturing the light-emitter of claim 15, wherein

the metal layer is formed on a lower layer having a visible reflectance of at least approximately 60%, and

the first electrode has a layer structure including the metal layer over the lower layer.

20. The method for manufacturing the light-emitter of claim 15, wherein

the metal layer is formed on a lower layer that is an alloy including at least one of aluminum and silver,

the metal layer includes at least one of molybdenum, chrome, vanadium, tungsten, nickel and iridium, and

the first electrode has a layer structure including the metal layer over the lower layer.

21. The method for manufacturing the light-emitter of claim 15, wherein the portion of the metal layer included in the first electrode has a film thickness of at most approximately 20 nm.