Light emitting device and method of fabricating the same

• US 9,608,225 B2
• Filed: 01/21/2010
• Issued: 03/28/2017
• Est. Priority Date: 01/21/2010
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd., Regents of the University of California (University of California)
• Original Assignee: Samsung Electronics Co. Ltd., Regents of the University of California (University of California)
• Inventors: Lee, Jae-Kwan, Kim, Do-Hwan, Lee, Sang-Yoon, Lee, Kwanghee, Park, Sung Heum, Cho, Shinuk, Heeger, Alan J.
• Primary Examiner(s): Yang, J. L.
• Application Number:
  US12/656,225
• Publication Number:
  US 20110175064A1
• Time in Patent Office: 2,623 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H10K 50/00 Organic light-emitting devices integrated devices or assemblies of multiple devices H10K59/00, H10K65/00; organic semiconductor lasers H01S5/36
• CPC Class Codes: H10K 50/125 specially adapted for multicolour light emission, e.g. for emitting white light
• CPC Class Codes: H10K 50/14 Carrier transporting layers
• CPC Class Codes: H10K 50/805 Electrodes
• CPC Class Codes: H10K 59/32 Stacked devices having two or more layers, each emitting at different wavelengths
• CPC Class Codes: H10K 59/805 Electrodes
• CPC Class Codes: H10K 71/00 Manufacture or treatment specially adapted for the organic devices covered by this subclass

Abstract

A light emitting device may include a first electrode on a substrate, a first emission layer on the first electrode, a buffer layer on the first emission layer, a middle electrode on the buffer layer, a second emission layer on the middle electrode, and a second electrode on the second emission layer. The buffer layer may include a material selected from the group consisting of a metal oxide, a polyelectrolyte, and a combination thereof. The first emission layer, buffer layer, middle electrode, and second emission layer may be fabricated using a wet process.

Claims

1. A light emitting device comprising:

a first electrode on a substrate;

a first emission layer on the first electrode;

a buffer layer on the first emission layer;

a middle electrode directly disposed on the buffer layer;

a second emission layer on the middle electrode; and

a second electrode on the second emission layer,

wherein the buffer layer includes a hole transporting polymer,

wherein the middle electrode includes a conductive polymer different from the hole transporting polymer, and

wherein the hole transporting polymer is represented by one of the following Chemical Formulae 1 to 3;

2. The light emitting device of claim 1, wherein the substrate includes a material selected from the group consisting of glass, quartz, silicon, a synthetic resin, a metal, and a combination thereof.

3. The light emitting device of claim 1, wherein the first electrode includes a material having a work function of about 4.3 eV to about 5.0 eV, and the second electrode includes a material having a work function of about 2.3 eV to about 2.7 eV.

4. The light emitting device of claim 1, wherein the middle electrode includes a material having a work function of about 4.3 eV to about 5.0 eV.

5. The light emitting device of claim 1, wherein the conductive polymer includes polythiophene, polyaniline, polypyrrole, polyacene, polyphenylene, polyphenylenevinylene, a derivative thereof, a copolymer thereof, or a mixture thereof.

6. The light emitting device of claim 1, wherein the conductive polymer includes polypyrrole, poly(3-methylpyrrole), poly(3-butylpyrrole), poly(3-octylpyrrole), poly(3-decylpyrrole), poly(3,4-dimethylpyrrole), poly(3,4-dibutylpyrrole), poly(3-hydroxylpyrrole), poly(3-methyl-4-hydroxylpyrrole), poly(3-methoxypyrrole), poly(3-ethoxypyrrole), poly(3-octoxypyrrole), poly(3-carboxylpyrrole), poly(3-methyl-4-carboxylpyrrole), poly(N-methylpyrrole), polythiophene, poly(3-methylthiophene), poly(3-butylthiophene), poly(3-octylthiophene), poly(3-decylthiophene), poly(3-dodecylthiophene), poly(3-methoxythiophene), poly(3-ethoxythiophene), poly(3-octoxythiophene), poly(3-carboxylthiophene), poly(3-methyl-4-carboxylthiophene), poly(3,4-ethylenedioxythiophene), polyaniline, poly(2-methylaniline), poly(2-octylaniline), poly(2-isobutylaniline), poly(3-isobutylaniline), poly(2-anilinesulfonic acid), poly(3-anilinesulfonic acid), or a mixture thereof.

7. The light emitting device of claim 1, wherein the conductive polymer is doped with a dopant.

8. The light emitting device of claim 1, wherein the hole transporting polymer has a weight average molecular weight of about 500 to about 20,000 g/mol.

9. The light emitting device of claim 1, further comprising:

a buffer layer between at least one of the first electrode and the first emission layer, and the second emission layer and the second electrode.

10. The light emitting device of claim 1, further comprising:

a hole blocking layer (HBL) between at least one of the first electrode and the first emission layer, and the second electrode and the second emission layer.

14. The light emitting device of claim 1, further comprising:

an electron transport layer (ETL) between at least one of the first electrode and the first light emission layer, and the second light emission layer and the second electrode.

11. A method of manufacturing a light-emitting device comprising:

providing a first electrode on a substrate;

providing a first emission layer on the first electrode;

providing a buffer layer on the first emission layer;

providing a middle electrode directly disposed on the buffer layer;

providing a second emission layer on the middle electrode; and

providing a second electrode on the second emission layer,

wherein the first emission layer, the buffer layer, the middle electrode, and the second emission layer are made using a wet process,

wherein the buffer layer includes a hole transporting polymer,

wherein the middle electrode includes a conductive polymer different from the hole transporting polymer, and

wherein the hole transporting polymer is represented by one of the following Chemical Formulae 1 to 3;

12. The method of claim 11, wherein the wet process includes at least one of gravure printing, off-set printing, screen printing, inkjet printing, spin coating, spray coating, or combinations thereof.

13. The method of claim 11, wherein the buffer layer is formed by coating a composition including a polyelectrolyte on the first emission layer directly.