Light-Emitting Device

Patent metadata

Field	Value
Publication number	US-2025151612-A1
Application number	US-202418932954-A
Country	US
Kind code	A1
Filing date	Oct 31, 2024
Priority date	Nov 2, 2023
Publication date	May 8, 2025
Grant date	—

Abstract

A light-emitting device with high reliability is provided. The light-emitting device includes a first electrode, a second electrode, and an EL layer. The EL layer is positioned between the first electrode and the second electrode. The EL layer includes a light-emitting layer and an electron-injection layer. The electron-injection layer contains a metal or an oxide of the metal, a first organic compound, and a second organic compound. The first organic compound includes a first π-electron deficient heteroaromatic ring with an electron-donating group. The second organic compound includes a second π-electron deficient heteroaromatic ring. The LUMO level of the second organic compound is lower than that of the first organic compound by 0.20 eV or more.

First claim

What is claimed is:

1 . A light-emitting device comprising:
a first electrode; a second electrode; and an EL layer, wherein the EL layer is positioned between the first electrode and the second electrode, wherein the EL layer comprises a light-emitting layer and an electron-injection layer, wherein the electron-injection layer comprises a metal or an oxide of the metal, a first organic compound, and a second organic compound, wherein the first organic compound is an organic compound comprising a first π-electron deficient heteroaromatic ring with an electron-donating group, wherein the second organic compound is an organic compound comprising a second π-electron deficient heteroaromatic ring, and wherein a LUMO level of the second organic compound is lower than a LUMO level of the first organic compound by 0.20 eV or more.

2 . The light-emitting device according to claim 1 ,
wherein the electron-injection layer is a mixed layer comprising the metal or the oxide of the metal, the first organic compound, and the second organic compound.

3 . The light-emitting device according to claim 1 ,
wherein the electron-injection layer comprises a stacked-layer structure of a first layer comprising the metal and a second layer comprising the first organic compound and the second organic compound, and wherein the first layer is closer to a cathode side than the second layer is.

4 . The light-emitting device according to claim 1 ,
wherein a relation LUMO1−0.80≤LUMO2≤LUMO1−0.20 is satisfied where the LUMO level of the first organic compound is LUMO1 (eV) and the LUMO level of the second organic compound is LUMO2 (eV).

5 . The light-emitting device according to claim 1 ,
wherein the first π-electron deficient heteroaromatic ring is a heteroaromatic ring comprising two or more pyridine rings.

6 . The light-emitting device according to claim 1 ,
wherein the first organic compound is an organic compound having an acid dissociation constant pK a larger than or equal to 8.

7 . The light-emitting device according to claim 1 ,
wherein the first π-electron deficient heteroaromatic ring and the second π-electron deficient heteroaromatic ring are different from each other.

8 . The light-emitting device according to claim 1 ,
wherein the second organic compound comprises at least one of an imidazole ring, a pyrazole ring, an oxazole ring, a thiazole ring, a triazole ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, and a triazine ring.

9 . The light-emitting device according to claim 1 ,
wherein the second organic compound has an acid dissociation constant pK a less than 4.

10 . The light-emitting device according to claim 1 ,
wherein the light-emitting layer comprises a third organic compound, wherein the third organic compound comprises a third π-electron deficient heteroaromatic ring, and wherein the third π-electron deficient heteroaromatic ring is the same as the second it-electron deficient heteroaromatic ring.

11 . The light-emitting device according to claim 1 ,
wherein the electron-donating group is any one or more of an alkyl group, an alkoxy group, an aryloxy group, an alkylamino group, an arylamino group, and a heterocyclic amino group.

12 . A light-emitting device that is one light-emitting device of a plurality of light-emitting devices included in a light-emitting device group, the light-emitting device group comprising:
a first electrode group formed over one insulating surface; a second electrode group facing the first electrode group; and an EL layer group positioned between the first electrode group and the second electrode group, wherein the light-emitting device comprises a first electrode, a second electrode, and an EL layer, wherein the first electrode is one included in the first electrode group, wherein the first electrode is independent for each of the plurality of light-emitting devices, wherein the EL layer is one included in the EL layer group, wherein the EL layer is independent for each of the plurality of light-emitting devices, wherein the second electrode is a continuous conductive layer shared by the plurality of light-emitting devices, wherein the second electrode and the EL layer overlap with the first electrode, wherein the EL layer comprises a light-emitting layer and an electron-injection layer, wherein the electron-injection layer comprises a metal or an oxide of the metal, a first organic compound, and a second organic compound, wherein the first organic compound is an organic compound comprising a first π-electron deficient heteroaromatic ring with an electron-donating group, wherein the second organic compound is an organic compound comprising a second π-electron deficient heteroaromatic ring, wherein a LUMO level of the second organic compound is lower than a LUMO level of the first organic compound by 0.20 eV or more, and wherein a distance between the EL layer included in the light-emitting device and the EL layer included in another light-emitting device adjacent to the light-emitting device is greater than or equal to 0.5 μm and less than or equal to 5 μm.

13 . The light-emitting device according to claim 12 ,
wherein the electron-injection layer is a mixed layer comprising the metal or the oxide of the metal, the first organic compound, and the second organic compound.

14 . The light-emitting device according to claim 12 ,
wherein the electron-injection layer comprises a stacked-layer structure of a first layer comprising the metal and a second layer comprising the first organic compound and the second organic compound, and wherein the first layer is closer to a cathode side than the second layer is.

15 . The light-emitting device according to claim 12 ,
wherein a relation LUMO1−0.80≤LUMO2≤LUMO1−0.20 is satisfied where the LUMO level of the first organic compound is LUMO1 (eV) and the LUMO level of the second organic compound is LUMO2 (eV).

16 . The light-emitting device according to claim 12 ,
wherein the first π-electron deficient heteroaromatic ring is a heteroaromatic ring comprising two or more pyridine rings.

17 . The light-emitting device according to claim 12 ,
wherein the first organic compound is an organic compound having an acid dissociation constant pK a larger than or equal to 8.

18 . The light-emitting device according to claim 12 ,
wherein the first π-electron deficient heteroaromatic ring and the second π-electron deficient heteroaromatic ring are different from each other.

19 . The light-emitting device according to claim 12 ,
wherein the second organic compound comprises at least one of an imidazole ring, a pyrazole ring, an oxazole ring, a thiazole ring, a triazole ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, and a triazine ring.

20 . The light-emitting device according to claim 12 ,
wherein the second organic compound has an acid dissociation constant pK a less than 4.

21 . The light-emitting device according to claim 12 ,
wherein the light-emitting layer comprises a third organic compound, wherein the third organic compound comprises a third π-electron deficient heteroaromatic ring, and wherein the third π-electron deficient heteroaromatic ring is the same as the second it-electron deficient heteroaromatic ring.

22 . The light-emitting device according to claim 12 ,
wherein the electron-donating group is any one or more of an alkyl group, an alkoxy group, an aryloxy

Assignees

• Semiconductor Energy Lab

Inventors

• Sasaki Toshiki
• Ohsawa Nobuharu
• Seo Hiromi
• Fukuzaki Shinya

Classifications

• H10K50/11 Primary

  characterised by the electroluminescent [EL] layers · CPC title

• H10K50/171

  Electron injection layers · CPC title

• H10K85/342

  comprising iridium · CPC title

• H10K85/633

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

• H10K85/6576

  comprising only sulfur in the heteroaromatic polycondensed ring system, e.g. benzothiophene · CPC title