Light-emitting device and display device

Patent metadata

Field	Value
Publication number	US-2025386702-A1
Application number	US-202519232097-A
Country	US
Kind code	A1
Filing date	Jun 9, 2025
Priority date	Jun 13, 2024
Publication date	Dec 18, 2025
Grant date	—

Abstract

A light-emitting device having favorable characteristics is provided. In the light-emitting device, an intermediate layer is positioned between first and second electrodes. A first light-emitting layer is positioned between the first electrode and the intermediate layer. A second light-emitting layer is positioned between the intermediate layer and the second electrode. The first light-emitting layer includes a first emission center substance and a first organic compound. The first organic compound includes deuterium. The second light-emitting layer includes a second emission center substance. The first emission center substance is a phosphorescent substance having an emission peak in a wavelength range of 440 nm to 500 nm. The difference between the maximum peak wavelengths of the PL spectra of the first and second emission center substances is 30 nm or less. The first and second light-emitting layers each emit light with a color gamut different from a color gamut of light emitted by a light-emitting layer included in at least one of adjacent light-emitting devices.

First claim

What is claimed is:

1 . A light-emitting device comprising:
a first electrode; a second electrode; an intermediate layer; a first light-emitting layer; and a second light-emitting layer, wherein the intermediate layer is between the first electrode and the second electrode, wherein the first light-emitting layer is between the first electrode and the intermediate layer, wherein the second light-emitting layer is between the intermediate layer and the second electrode, wherein the first light-emitting layer comprises a first emission center substance and a first organic compound, wherein the first organic compound comprises deuterium, wherein the second light-emitting layer comprises a second emission center substance, wherein the first emission center substance is a phosphorescent substance having an emission peak at a wavelength longer than or equal to 440 nm and shorter than or equal to 500 nm, wherein a difference between a maximum peak wavelength of a PL spectrum of the first emission center substance and a maximum peak wavelength of a PL spectrum of the second emission center substance is less than or equal to 30 nm, and wherein the first light-emitting layer and the second light-emitting layer each emit light with a color gamut different from a color gamut of light emitted by a light-emitting layer included in at least one of a plurality of adjacent light-emitting devices.

2 . A light-emitting device comprising:
a first electrode; a second electrode; an intermediate layer; a first light-emitting layer; and a second light-emitting layer, wherein the intermediate layer is between the first electrode and the second electrode, wherein the first light-emitting layer is between the first electrode and the intermediate layer, wherein the second light-emitting layer is between the intermediate layer and the second electrode, wherein the first light-emitting layer comprises a first emission center substance, a first organic compound, and a second organic compound, wherein at least one of the first organic compound and the second organic compound comprises deuterium, wherein the second light-emitting layer comprises a second emission center substance, wherein the first emission center substance is a phosphorescent substance having an emission peak at a wavelength longer than or equal to 440 nm and shorter than or equal to 500 nm, wherein a difference between a maximum peak wavelength of a PL spectrum of the first emission center substance and a maximum peak wavelength of a PL spectrum of the second emission center substance is less than or equal to 30 nm, and wherein the first light-emitting layer and the second light-emitting layer each emit light with a color gamut different from a color gamut of light emitted by a light-emitting layer included in at least one of a plurality of adjacent light-emitting devices.

3 . The light-emitting device according to claim 2 ,
wherein the first organic compound comprises a π-electron deficient heteroaromatic ring, and wherein the second organic compound comprises at least one of a π-electron rich heteroaromatic ring and an aromatic amine skeleton.

4 . The light-emitting device according to claim 3 ,
wherein the second light-emitting layer comprises the second emission center substance, a third organic compound, and a fourth organic compound, wherein the third organic compound comprises a π-electron deficient heteroaromatic ring, wherein the fourth organic compound comprises at least one of a-electron rich heteroaromatic ring and an aromatic amine skeleton, wherein at least one of the third organic compound and the fourth organic compound comprises deuterium, wherein a combination of the first organic compound and the second organic compound forms a first exciplex, wherein a combination of the third organic compound and the fourth organic compound forms a second exciplex, wherein an emission edge on a shorter wavelength side of a PL spectrum of the first exciplex is positioned at a shorter wavelength than an absorption edge on a longer wavelength side of an absorption spectrum of the first emission center substance, and wherein an emission edge on a shorter wavelength side of a PL spectrum of the second exciplex is positioned at a shorter wavelength than an absorption edge on a longer wavelength side of an absorption spectrum of the second emission center substance.

5 . The light-emitting device according to claim 4 ,
wherein a difference between a lowest triplet excitation energy level of the first organic compound and a lowest triplet excitation energy level of the second organic compound is less than or equal to 0.20 eV, and wherein a difference between a lowest triplet excitation energy level of the third organic compound and a lowest triplet excitation energy level of the fourth organic compound is less than or equal to 0.20 eV.

6 . The light-emitting device according to claim 4 ,
wherein a phosphorescence lifetime or a delayed fluorescence lifetime at 77 K of the first organic compound is 1.20 times or more a phosphorescence lifetime or a delayed fluorescence lifetime at 77 K of a fifth organic compound that is a non-deuterated substance of the first organic compound, and wherein a phosphorescence lifetime or a delayed fluorescence lifetime at 77 K of the second organic compound is 1.05 times or more a phosphorescence lifetime or a delayed fluorescence lifetime at 77 K of a sixth organic compound that is a non-deuterated substance of the second organic compound.

7 . The light-emitting device according to claim 4 , wherein a product of X and Y is greater than or equal to 1.26 when a phosphorescence lifetime or a delayed fluorescence lifetime at 77 K of the first organic compound is X times a phosphorescence lifetime or a delayed fluorescence lifetime at 77 K of a fifth organic compound that is a non-deuterated substance of the first organic compound and a phosphorescence lifetime or a delayed fluorescence lifetime at 77 K of the second organic compound is Y times a phosphorescence lifetime or a delayed fluorescence lifetime at 77 K of a sixth organic compound that is a non-deuterated substance of the second organic compound.

8 . The light-emitting device according to claim 1 , wherein the first emission center substance is the same substance as the second emission center substance.

9 . The light-emitting device according to claim 1 , wherein the first emission center substance is a platinum complex.

10 . The light-emitting device according to claim 1 , further comprising:
a first hole-transport layer between the first electrode and the first light-emitting layer; and a second hole-transport layer between the intermediate layer and the second light-emitting layer, wherein the first hole-transport layer or the second hole-transport layer has a stacked-layer structure comprising at least a first layer comprising a seventh organic compound and a second layer comprising an eighth organic compound, wherein the second layer is in contact with the first light-emitting layer or the second light-emitting layer, wherein the seventh organic compound comprises an amine skeleton and a polycyclic hydrocarbon, and wherein the eighth organic compound comprises a π-electron rich polycyclic heteroaromatic ring.

11 . The light-emitting device according to claim 1 , further comprising:
a first electron-transport layer between the second light-emitting layer and the second electrode, wherein the first electron-transport layer comprises a layer comprising a ninth organic compound comprising a triazine skeleton, and wherein the intermediate layer comprises a first mixed layer of lithium o

Assignees

• Semiconductor Energy Lab

Inventors

• Seo Satoshi
• Ohsawa Nobuharu
• Seo Hiromi
• Kido Hiromitsu
• Hayashi Yuki

Classifications

• H10K50/11

  characterised by the electroluminescent [EL] layers · CPC title

• H10K85/346

  comprising platinum · CPC title

• H10K85/40

  Organosilicon compounds, e.g. TIPS pentacene · CPC title

• H10K85/6574

  comprising only oxygen in the heteroaromatic polycondensed ring system, e.g. cumarine dyes · CPC title

• H10K85/342

  comprising iridium · CPC title