Light emitting element, display device including the same, and method for manufacturing the light emitting element

Patent metadata

Field	Value
Publication number	US-12178115-B2
Application number	US-202117450160-A
Country	US
Kind code	B2
Filing date	Oct 6, 2021
Priority date	Jan 4, 2021
Publication date	Dec 24, 2024
Grant date	Dec 24, 2024

Abstract

A light emitting element includes a first electrode, a hole transport region on the first electrode, an emission layer on the hole transport region and containing a light emitting polymer compound derived from a mixture of a polyphenylene vinylene-based compound having a weight average molecular weight of about 1.3×10 6 to about 1.6×10 6 and an organic compound represented by Formula 1, and a second electrode on the emission layer, wherein, the mixture contains the polyphenylene vinylene-based compound and the organic compound in a molar ratio of about 9:1 to about 8:2, and the light emitting element may thus include an emission layer having improved flexibility and strength.

First claim

What is claimed is:

1. A light emitting element comprising:
a first electrode;
a hole transport region on the first electrode;
an emission layer on the hole transport region and comprising a light emitting polymer compound derived from a first mixture of a polyphenylene vinylene-based compound having a weight average molecular weight of about 1.3×10 6 to about 1.6×10 6 and an organic compound represented by Formula 1; and
a second electrode on the emission layer,
wherein, in the first mixture, the polyphenylene vinylene-based compound and the organic compound have a molar ratio of about 9:1 to about 8:2,
wherein the polyphenylene vinylene-based compound is poly(1,4-phenylene vinylene),

wherein in Formula 1,
n is an integer of 5 to 20, and
a and b are each independently 2, and
wherein the hole transport region comprises a hole transport polymer compound derived from a crosslinking reaction of a second mixture of a hole-transporting polymer and an organic compound, the organic compound being a crosslinking agent for the hole-transporting polymer.

2. The light emitting element of claim 1 , wherein the light emitting polymer compound is formed when the polyphenylene vinylene-based compound is cross-linked with the organic compound.

3. The light emitting element of claim 1 , wherein
the hole transport region comprises a hole injection layer, and a hole transport layer on the hole injection layer, and
at least one of the hole injection layer or the hole transport layer comprises the hole transport polymer compound.

4. The light emitting element of claim 1 , further comprising an electron transport region between the emission layer and the second electrode,
wherein the electron transport region comprises an electron transport polymer compound derived from a crosslinking reaction of a mixture of an electron-transporting polymer and an organic compound, the organic compound being a crosslinking agent for the electron-transporting polymer.

5. The light emitting element of claim 4 , wherein the electron transport region comprises an electron injection layer, and an electron transport layer on the electron injection layer, and
at least one of the electron injection layer or the electron transport layer comprises the electron transport polymer compound.

6. A display device comprising:
a base layer; and
a light emitting element on the base layer,
wherein the light emitting element comprises:
a first electrode;
a hole transport region on the first electrode;
an emission layer on the hole transport region and comprising a light emitting polymer compound derived from a first mixture of a polyphenylene vinylene-based compound having a weight average molecular weight of about 1.3×10 6 to about 1.6×10 6 and an organic compound represented by Formula 1; and
a second electrode on the emission layer,
wherein in the first mixture, the polyphenylene vinylene-based compound and the organic compound have a molar ratio of about 9:1 to about 8:2,
wherein the polyphenylene vinylene-based compound is poly(1,4-phenylene vinylene),

wherein in Formula 1,
n is an integer of 5 to 20, and
a and b are each independently 2, and
wherein the hole transport region comprises a hole transport polymer compound derived from a crosslinking reaction of a second mixture of a hole-transporting polymer and an organic compound, the organic compound being a crosslinking agent for the hole-transporting polymer.

7. The display device of claim 6 , wherein the light emitting polymer compound is formed when the polyphenylene vinylene-based compound and the organic compound are cross-linked.

8. The display device of claim 6 , wherein
the hole transport region comprises a hole injection layer, and a hole transport layer on the hole injection layer, and
at least one of the hole injection layer or the hole transport layer comprises the hole transport polymer compound.

9. The display device of claim 6 , wherein the display device comprises:
a first state having a first area on a plane; and
a second state having a second area larger than the first area on the plane.

10. The display device of claim 6 , wherein
the display device has a folded state and a non-folded state, and
in the folded state, the display device comprises a folding area that is folded with respect to a folding axis, which is a virtual line extending in a first direction, and a first non-folding area and a second non-folding area spaced apart from each other in a second direction crossing the first direction with respect to the folding area.

11. The display device of claim 6 , wherein the emission layer has flexibility.

12. A method for manufacturing a light emitting element, the method comprising:
forming a hole transport region on a first electrode;
providing a first mixture containing a polyphenylene vinylene-based compound and an organic compound represented by Formula 1 in a molar ratio of about 9:1 to about 8:2 on the hole transport region to form an emission layer; and
forming a second electrode on the emission layer,
wherein the polyphenylene vinylene-based compound is poly(1,4-phenylene vinylene),

wherein in Formula 1,
n is an integer of 5 to 20, and
a and b are each independently 2, and
wherein the hole transport region comprises a hole transport polymer compound derived from a crosslinking reaction of a second mixture of a hole-transporting polymer and an organic compound, the organic compound being a crosslinking agent for the hole-transporting polymer.

13. The method of claim 12 , wherein the forming of the emission layer comprises depositing the first mixture through inkjet printing.

14. The method of claim 12 , wherein the forming of the emission layer comprises:
depositing the first mixture; and
providing heat or ultraviolet light to the first mixture.

15. The method of claim 14 , wherein the providing of heat or ultraviolet light to the first mixture comprises crosslinking the polyphenylene vinylene-based compound and the organic compound.

Assignees

• Samsung Display Co Ltd

Inventors

• Park Junwoo

Classifications

• H10K71/40

  Thermal treatment, e.g. annealing in the presence of a solvent vapour · CPC title

• H10K85/114 Primary

  Poly-phenylenevinylene; Derivatives thereof · CPC title

• H10K50/12 Primary

  comprising dopants · CPC title

• H10K71/00

  Manufacture or treatment specially adapted for the organic devices covered by this subclass · CPC title

• H10K50/171

  Electron injection layers · CPC title