Light-emitting element, and display device including the same

Patent metadata

Field	Value
Publication number	US-2025212665-A1
Application number	US-202418954314-A
Country	US
Kind code	A1
Filing date	Nov 20, 2024
Priority date	Dec 21, 2023
Publication date	Jun 26, 2025
Grant date	—

Abstract

Provided is a light-emitting element including a first electrode, a second electrode facing the first electrode, an emission structure between the first electrode and the second electrode, a first capping layer which is on the second electrode and includes a first compound having a first refractive index of about 1.9 or greater at a wavelength of about 550 nm and a metal dopant having an absorption ratio of about 40% at the wavelength of about 550 nm, and a second capping layer which is on the first capping layer and includes a second compound having second refractive index smaller than the first refractive index, and thus reflectance for external light decrease, thereby exhibiting excellent efficiency characteristics.

First claim

What is claimed is:

1 . A light-emitting element comprising:
a first electrode; a second electrode facing the first electrode; an emission structure between the first electrode and the second electrode; a first capping layer on the second electrode and comprising a first compound having a first refractive index of about 1.9 or greater at a wavelength of about 550 nm and a metal dopant having an absorption ratio of about 40% or more at the wavelength of about 550 nm; and a second capping layer on the first capping layer and comprising a second compound having a second refractive index smaller than the first refractive index.

2 . The light-emitting element of claim 1 , wherein a difference between the first refractive index and the second refractive index is about 0.2 or greater.

3 . The light-emitting element of claim 2 , wherein the second refractive index is about 1.4 to about 1.7.

4 . The light-emitting element of claim 1 , wherein the metal dopant is an alkali metal, an alkaline earth metal, a lanthanide metal, and/or a transition metal.

5 . The light-emitting element of claim 1 , wherein the metal dopant is lithium (Li) and/or ytterbium (Yb).

6 . The light-emitting element of claim 1 , wherein a volume ratio of the first compound to the metal dopant in the first capping layer is about 99:1 to about 95:5.

7 . The light-emitting element of claim 1 , wherein thicknesses of the first capping layer and the second capping layer are each independently about 100 Å to about 500 Å.

8 . The light-emitting element of claim 1 , wherein the emission structure comprises an emission layer on the first electrode, a hole transport region between the first electrode and the emission layer, and an electron transport region between the emission layer and the second electrode.

9 . The light-emitting element of claim 1 , wherein the emission structure comprises:
a plurality of emission units, which are sequentially stacked and each comprises a hole transport region, an emission layer and an electron transport region, and a charge generation layer, which are between each of the plurality of emission units between the first electrode and the second electrode.

10 . The light-emitting element of claim 1 , wherein the emission structure emits blue light.

11 . The light-emitting element of claim 1 , wherein the first compound is an organic material, and the second compound is an organic material or inorganic material.

12 . A display device comprising:
a light-emitting element that emits a source light; and an optical control layer on the light-emitting element and configured to transmit the source light or convert a wavelength of the source light, wherein the light-emitting element comprises: a first electrode; a second electrode facing the first electrode; an emission structure between the first electrode and the second electrode; a first capping layer on the second electrode and comprising a first compound having a first refractive index of about 1.9 or greater at a wavelength of 550 nm, and a metal dopant having an absorption ratio of about 40% or more at the wavelength of 550 nm; and a second capping layer on the first capping layer and comprising a second compound having a second refractive index smaller than the first refractive index.

13 . The display device of claim 12 , wherein a difference between the first refractive index and the second refractive index is about 0.2 or greater, and the second refractive index is about 1.4 to about 1.7.

14 . The display device of claim 12 , wherein the metal dopant is an alkali metal, an alkaline earth metal, a lanthanide metal, and/or a transition metal.

15 . The display device of claim 12 , wherein a volume ratio of the first compound to the metal dopant in the first capping layer is about 99:1 to about 95:5.

16 . The display device of claim 12 , wherein thicknesses of the first capping layer and the second capping layer are each independently about 100 Å to about 500 Å.

17 . The display device of claim 12 comprising:
a first pixel region that emits red light;
a second pixel region that emits green light; and
a third pixel region that emits blue light, wherein the first pixel region, the second pixel region, and the third pixel region do not overlap on a plane,
wherein the optical control layer comprises:
a first optical control member provided corresponding to the first pixel region and comprising a first quantum dot which converts a wavelength of the source light;
a second optical control member provided corresponding to the second pixel region and comprising a second quantum dot which converts a wavelength of the source light; and
a third optical control member provided corresponding to the third pixel region.

18 . A display device comprising:
a circuit layer; a light-emitting element on the circuit layer; and an encapsulation layer on the light-emitting element, wherein the light-emitting element comprises: a first electrode; a second electrode facing the first electrode; an emission structure between the first electrode and the second electrode; a first capping layer on the second electrode and comprising a first compound having a first refractive index of about 1.9 or greater at a wavelength of 550 nm and a metal dopant having an absorption ratio of about 40% or more at the wavelength of 550 nm, and a second capping layer on the first capping layer and comprising a second compound having a second refractive index smaller than the first refractive index.

19 . The display device of claim 18 , wherein the encapsulation layer is directly on the second capping layer.

20 . The display device of claim 18 , wherein a volume ratio of the first compound to the metal dopant in the first capping layer is about 99:1 to about 95:5.

Assignees

• Samsung Display Co Ltd

Inventors

• Lee Hakchoong
• Lee Jongwon
• Lee Chang-Min
• Cho Yoonhyeung
• Hwang Jaehoon

Classifications

• H10H20/852

  Encapsulations · CPC title

• H10H20/812

  within the light-emitting regions, e.g. having quantum confinement structures · CPC title

• H10H29/142

  Two-dimensional arrangements, e.g. asymmetric LED layout · CPC title

• H10H20/84 Primary

  Coatings, e.g. passivation layers or antireflective coatings · CPC title

• H10K59/8792

  comprising light absorbing layers, e.g. black layers · CPC title