Light-emitting device

Patent metadata

Field	Value
Publication number	US-12200953-B2
Application number	US-201917781336-A
Country	US
Kind code	B2
Filing date	Dec 4, 2019
Priority date	Dec 4, 2019
Publication date	Jan 14, 2025
Grant date	Jan 14, 2025

Abstract

A light-emitting device includes an HTL including a metal chalcogenide between an anode and an EML, with an IL including an organic material at least between the HTL and the EML. A distance between the HTL and the EML in a light-emitting element that emits light in a wavelength band having the shortest light emission peak wavelength is greater than a distance between the HTL and the EML in each of the other light-emitting elements.

First claim

The invention claimed is:

1. A light-emitting device comprising:
a plurality of types of light-emitting elements each having a light emission peak wavelength in a different wavelength band,
wherein the plurality of types of light-emitting elements each include, in this order,
an anode,
a light-emitting layer including quantum dots, and
a cathode,
a layer having hole transport properties and including a metal chalcogenide being between the anode and the light-emitting layer, and
an intermediate layer including an organic material being between the light-emitting layer and at least the layer including the metal chalcogenide of, among the plurality of types of light-emitting elements, a light-emitting element that emits light in a wavelength band having the shortest light emission peak wavelength, and
a distance between the light-emitting layer and the layer including the metal chalcogenide of, among the plurality of types of light-emitting elements, the light-emitting element that emits light in a wavelength band having the shortest light emission peak wavelength is greater than a distance between the light-emitting layer and the layer including the metal chalcogenide of each of the other light-emitting elements,
wherein the intermediate layer is provided between the light-emitting layer and the layer including the metal chalcogenide in each of the plurality of types of light-emitting elements.

2. The light-emitting device according to claim 1 ,
wherein the metal chalcogenide is at least one type selected from the group consisting of nickel oxide, copper oxide, and copper sulfide.

3. The light-emitting device according to claim 1 ,
wherein the intermediate layer is an insulating layer.

4. The light-emitting device according to claim 3 ,
wherein the distance between the light-emitting layer and the layer including the metal chalcogenide of the light-emitting element that emits light in a wavelength band having the shortest light emission peak wavelength is within a range from 0.5 nm to 12.5 nm.

5. The light-emitting device according to claim 3 ,
wherein a difference between the distance between the light-emitting layer and the layer including the metal chalcogenide of the light-emitting element that emits light in a wavelength band having the shortest light emission peak wavelength and the distance between the light-emitting layer and the layer including the metal chalcogenide of each of the other light-emitting elements is within a range from 0.5 nm to 12.5 nm.

6. The light-emitting device according to claim 3 ,
wherein the insulating layer is composed of at least one type of insulating material selected from the group consisting of polymethyl methacrylate, polyvinyl pyrrolidone, and poly[(9,9-bis(3′-(N,N-dimethylamino) propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)].

7. The light-emitting device according to claim 1 ,
wherein the layer including the metal chalcogenide is a hole injection layer, and
the intermediate layer is a hole transport layer.

8. The light-emitting device according to claim 7 ,
wherein the distance between the light-emitting layer and the layer including the metal chalcogenide of the light-emitting element that emits light in a wavelength band having the shortest light emission peak wavelength is within a range from 30.5 nm to 60 nm.

9. The light-emitting device according to claim 7 ,
wherein the difference between the distance between the light-emitting layer and the layer including the metal chalcogenide of the light-emitting element that emits light in a wavelength band having the shortest light emission peak wavelength and the distance between the light-emitting layer and the layer including the metal chalcogenide of each of the other light-emitting elements is within a range from 0.5 nm to 30 nm.

10. The light-emitting device according to claim 7 ,
wherein the hole transport layer includes at least one type of organic hole transport material selected from the group consisting of poly(N-vinylcarbazole) and poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4′-(N-4-sec-butylphenyl))diphenylamine)].

11. The light-emitting device according to claim 1 ,
wherein the quantum dots of the plurality of types of light-emitting elements each include a core and a shell covering the core, and
a thickness of the shell of the quantum dots of the light-emitting element that emits light in a wavelength band having the shortest light emission peak wavelength is thinner than a thickness of the shell of the quantum dots of each of the other light-emitting elements.

12. The light-emitting device according to claim 1 ,
wherein the light-emitting layer of each of the plurality of types of light-emitting elements includes a ligand adsorbed on a surface of each of the quantum dots, and
a length of the ligand in the light-emitting element that emits light in a wavelength band having the shortest light emission peak wavelength is shorter than a length of the ligand in each of the other light-emitting elements.

13. The light-emitting device according to claim 1 ,
wherein the plurality of types of light-emitting elements each include an electron transport layer between the cathode and the light-emitting layer, and
a material of the electron transport layer in the light-emitting element that emits light in a wavelength band having the shortest light emission peak wavelength is the same as a material of the electron transport layer in at least a portion of light-emitting elements of the other light-emitting elements.

14. The light-emitting device according to claim 1 ,
wherein a level of a conduction band lower end of the light-emitting layer in the light-emitting element that emits light in a wavelength band having the shortest light emission peak wavelength is shallower than a level of a conduction band lower end of the light-emitting layer of each of the other light-emitting elements.

15. The light-emitting device according to claim 1 ,
wherein the light-emitting element that emits light in a wavelength band having the shortest light emission peak wavelength is a light-emitting element that emits blue light, and
the other light-emitting elements are a light-emitting element that emits red light and a light-emitting element that emits green light.

16. A light-emitting device comprising:
a plurality of types of light-emitting elements each having a light emission peak wavelength in a different wavelength band,
wherein the plurality of types of light-emitting elements each include, in this order,
an anode,
a light-emitting layer including quantum dots, and
a cathode,
a layer having hole transport properties and including a metal chalcogenide being between the anode and the light-emitting layer, and
an intermediate layer including an organic material being between the light-emitting layer and at least the layer including the metal chalcogenide of, among the plurality of types of light-emitting elements, a light-emitting element that emits light in a wavelength band having the shortest light emission peak wavelength, and
a distance between the light-emitting layer and the layer including the metal chalcogenide of, among the plurality of types of light-emitting elements, the light-emitting element that emits light in a wavelength band having the shortest light emission peak wavelength is greater than a distance between the light-emitting layer and the layer including the metal chalcogenide of each of the other light-emitting elements,
wherein the intermediate layer is an insulating layer.

17. The light-emitting device according to

Assignees

• Sharp Kk

Inventors

• Naka Takayuki
• Ueta Yoshihiro
• Iwata Noboru

Classifications

• H10K50/17 Primary

  Carrier injection layers · CPC title

• H10K50/115 Primary

  comprising active inorganic nanostructures, e.g. luminescent quantum dots · CPC title

• H10K2102/00

  Constructional details relating to the organic devices covered by this subclass · CPC title

• H10K50/15

  Hole transporting layers · CPC title

• H10K85/114

  Poly-phenylenevinylene; Derivatives thereof · CPC title