Light-emitting element, light-emitting device, display device, electronic appliance, and lighting device

Patent metadata

Field	Value
Publication number	US-12439814-B2
Application number	US-202418606779-A
Country	US
Kind code	B2
Filing date	Mar 15, 2024
Priority date	Aug 3, 2012
Publication date	Oct 7, 2025
Grant date	Oct 7, 2025

Abstract

A multicolor light-emitting element using fluorescence and phosphorescence, which has a small number of manufacturing steps owing to a relatively small number of layers to be formed and is advantageous for practical application can be provided. In addition, a multicolor light-emitting element using fluorescence and phosphorescence, which has favorable emission efficiency is provided. A light-emitting element which includes a light-emitting layer having a stacked-layer structure of a first light-emitting layer exhibiting light emission from a first exciplex and a second light-emitting layer exhibiting phosphorescence is provided.

First claim

The invention claimed is:

1. A light-emitting element comprising:
an anode;
a hole-transport layer over the anode;
a first light-emitting layer over the hole-transport layer, the first light-emitting layer comprising a first organic compound and a phosphorescent compound;
a second light-emitting layer over and in contact with the first light-emitting layer, the second light-emitting layer comprising a second organic compound and a third organic compound;
an electron-transport layer over the second light-emitting layer; and
a cathode over the electron-transport layer,
wherein each of a triplet excited level of the second organic compound and the third organic compound is higher than a triplet excited level of the phosphorescent compound,
wherein a combination of the second organic compound and the third organic compound forms a first exciplex,
wherein light emitted from the first light-emitting layer has an emission peak at 600 nm to 700 nm, and
wherein light emitted from the second light-emitting layer has an emission peak at 500 nm to 600 nm.

2. The light-emitting element according to claim 1 , wherein the second light-emitting layer further comprises a dopant.

3. The light-emitting element according to claim 2 , wherein the dopant is a light-emitting substance.

4. A light-emitting module including the light-emitting element according to claim 1 , the light-emitting module comprising:
a current controlling transistor electrically connected to the light-emitting element.

5. A display module including the light-emitting element according to claim 1 in a display portion, the display module comprising:
a current controlling transistor electrically connected to the light-emitting element.

6. A lighting device including the light-emitting element according to claim 1 .

7. A light-emitting device comprising:
the light-emitting element according to claim 1 ; and
a current controlling transistor electrically connected to the light-emitting element.

8. A display device comprising:
the light-emitting element according to claim 1 in a display portion; and
a current controlling transistor electrically connected to the light-emitting element.

9. An electronic appliance comprising the light-emitting element according to claim 1 .

10. A light-emitting element comprising:
an anode;
a hole-transport layer over the anode;
a first light-emitting layer over the hole-transport layer, the first light-emitting layer comprising a first organic compound and a phosphorescent compound;
a second light-emitting layer between the hole-transport layer and the first light-emitting layer, the second light-emitting layer comprising a second organic compound and a third organic compound;
an electron-transport layer over the second light-emitting layer; and
a cathode over the electron-transport layer,
wherein the second light-emitting layer is in contact with the first light-emitting layer,
wherein each of a triplet excited level of the second organic compound and the third organic compound is higher than a triplet excited level of the phosphorescent compound,
wherein a combination of the second organic compound and the third organic compound forms a first exciplex,
wherein light emitted from the first light-emitting layer has an emission peak at 600 nm to 700 nm, and
wherein light emitted from the second light-emitting layer has an emission peak at 500 nm to 600 nm.

11. The light-emitting element according to claim 10 , wherein the second light-emitting layer further comprises a dopant.

12. The light-emitting element according to claim 11 , wherein the dopant is a light-emitting substance.

13. A light-emitting module including the light-emitting element according to claim 10 , the light-emitting module comprising:
a current controlling transistor electrically connected to the light-emitting element.

14. A display module including the light-emitting element according to claim 10 in a display portion, the display module comprising:
a current controlling transistor electrically connected to the light-emitting element.

15. A lighting device including the light-emitting element according to claim 10 .

16. A light-emitting device comprising:
the light-emitting element according to claim 10 ; and
a current controlling transistor electrically connected to the light-emitting element.

17. A display device comprising:
the light-emitting element according to claim 10 in a display portion; and
a current controlling transistor electrically connected to the light-emitting element.

18. An electronic appliance comprising the light-emitting element according to claim 10 .

Assignees

• Semiconductor Energy Lab

Inventors

• Seo Satoshi
• Seo Hiromi
• Takahashi Tatsuyoshi
• Ishisone Takahiro

Classifications

• H10K50/16

  Electron transporting layers · CPC title

• H10K50/15

  Hole transporting layers · CPC title

• H10K50/82

  Cathodes · CPC title

• H10K50/81

  Anodes · CPC title

• H10K2101/25

  using exciplex · CPC title