Light-emitting element, light-emitting device, electronic device, lighting device, and organic compound

Patent metadata

Field	Value
Publication number	US-12127479-B2
Application number	US-202318381846-A
Country	US
Kind code	B2
Filing date	Oct 19, 2023
Priority date	Jul 25, 2014
Publication date	Oct 22, 2024
Grant date	Oct 22, 2024

Abstract

To provide a light-emitting element with an improved reliability, a light-emitting element with a high current efficiency (or a high quantum efficiency), and a novel dibenzo[f,h]quinoxaline derivative that is favorably used in a light-emitting element which is one embodiment of the present invention. A light-emitting element includes an EL layer between an anode and a cathode. The EL layer includes a light-emitting layer; the light-emitting layer contains a first organic compound having an electron-transport property and a hole-transport property, a second organic compound having a hole-transport property, and a light-emitting substance; the combination of the first organic compound and the second organic compound forms an exciplex; the HOMO level of the first organic compound is lower than the HOMO level of the second organic compound; and a difference between the HOMO level of the first organic compound and the HOMO level of the second organic compound is less than or equal to 0.4 eV.

First claim

What is claimed is:

1. A light-emitting element comprising:
a light-emitting layer between an anode and a cathode,
wherein the light-emitting layer comprises a first organic compound, a second organic compound, and a phosphorescent compound,
wherein an emission spectrum of a mixed film of the first organic compound and the second organic compound is located on a longer wavelength side than a fluorescence spectrum of a film of the first organic compound and a fluorescence spectrum of a film of the second organic compound,
wherein the first organic compound comprises a 6-membered nitrogen-containing heteroaromatic ring and a carbazole skeleton and does not comprise a triarylamine skeleton,
wherein the 6-membered nitrogen-containing heteroaromatic ring is pyrazine, pyridazine, triazine, or tetrazine,
wherein a HOMO level of the first organic compound is lower than a HOMO level of the second organic compound, and
wherein a difference between the HOMO level of the first organic compound and the HOMO level of the second organic compound is less than or equal to 0.4 eV.

2. A light-emitting element comprising:
a light-emitting layer between an anode and a cathode,
wherein the light-emitting layer comprises a first organic compound, a second organic compound, and a phosphorescent compound,
wherein the first organic compound and the second organic compound form an exciplex,
wherein the first organic compound comprises a 6-membered nitrogen-containing heteroaromatic ring and a carbazole skeleton and does not comprise a triarylamine skeleton,
wherein the 6-membered nitrogen-containing heteroaromatic ring is pyrazine, pyridazine, triazine, or tetrazine,
wherein a HOMO level of the first organic compound is lower than a HOMO level of the second organic compound, and
wherein a difference between the HOMO level of the first organic compound and the HOMO level of the second organic compound is less than or equal to 0.4 eV.

3. A light-emitting element comprising:
a light-emitting layer between an anode and a cathode,
wherein the light-emitting layer comprises a first organic compound, a second organic compound, and a phosphorescent compound,
wherein an emission spectrum of a mixed film of the first organic compound and the second organic compound is located on a longer wavelength side than a fluorescence spectrum of a film of the first organic compound and a fluorescence spectrum of a film of the second organic compound,
wherein the first organic compound comprises a 6-membered nitrogen-containing heteroaromatic ring and a carbazole skeleton and does not comprise a triarylamine skeleton,
wherein a HOMO level of the first organic compound is lower than a HOMO level of the second organic compound,
wherein a difference between the HOMO level of the first organic compound and the HOMO level of the second organic compound is less than or equal to 0.4 eV, and wherein the 6-membered nitrogen-containing heteroaromatic ring is condensed with a benzene ring.

4. The light-emitting element according to claim 1 , wherein the phosphorescent compound comprises iridium.

5. The light-emitting element according to claim 1 , wherein the difference between the HOMO level of the first organic compound and the HOMO level of the second organic compound is less than or equal to 0.3 eV.

6. The light-emitting element according to claim 2 , wherein the phosphorescent compound comprises iridium.

7. The light-emitting element according to claim 2 , wherein the difference between the HOMO level of the first organic compound and the HOMO level of the second organic compound is less than or equal to 0.3 eV.

8. The light-emitting element according to claim 3 , wherein the phosphorescent compound comprises iridium.

9. The light-emitting element according to claim 3 , wherein the difference between the HOMO level of the first organic compound and the HOMO level of the second organic compound is less than or equal to 0.3 eV.

10. The light-emitting element according to claim 3 , wherein the first organic compound and the second organic compound form an exciplex.

11. The light-emitting element according to claim 3 , wherein the 6-membered nitrogen-containing heteroaromatic ring is pyridine, pyrazine, pyrimidine, pyridazine, triazine, or tetrazine.

12. The light-emitting element according to claim 3 , wherein the 6-membered nitrogen-containing heteroaromatic ring condensed with the benzene ring is quinoline, isoquinoline, dibenzo[f,h]quinoline, naphthyridine, dibenzo[f,h]quinoxaline, oρ dibenzo[f,h]quinazoline.

13. A light-emitting device comprising the light-emitting element according to claim 1 .

14. An electronic device comprising:
the light-emitting device according to claim 13 ; and
at least one of a connection terminal and an operation key.

15. A light-emitting device comprising the light-emitting element according to claim 2 .

16. An electronic device comprising:
the light-emitting device according to claim 15 ; and
at least one of a connection terminal and an operation key.

17. A light-emitting device comprising the light-emitting element according to claim 3 .

18. An electronic device comprising:
the light-emitting device according to claim 17 ; and
at least one of a connection terminal and an operation key.

Assignees

• Semiconductor Energy Lab

Inventors

• Seo Satoshi
• Hamada Takao
• Takahashi Tatsuyoshi
• Kitano Yasushi
• Suzuki Hiroki
• Inoue Hideko

Classifications

• H10K85/636

  comprising heteroaromatic hydrocarbons as substituents on the nitrogen atom · CPC title

• H10K85/633

  comprising polycyclic condensed aromatic hydrocarbons as substituents on the nitrogen atom · CPC title

• H10K85/342

  comprising iridium · CPC title

• Y02P20/582

  Recycling of unreacted starting or intermediate materials · CPC title

• C07D403/14 Primary

  containing three or more hetero rings · CPC title