Light emitting element, light emitting device, and method for manufacturing light emitting element

Patent metadata

Field	Value
Publication number	US-2021351244-A1
Application number	US-201817277627-A
Country	US
Kind code	A1
Filing date	Sep 21, 2018
Priority date	Sep 21, 2018
Publication date	Nov 11, 2021
Grant date	—

Abstract

A light-emitting element includes: pixel electrodes provided for individual subpixels of at least three colors; a common electrode provided facing each of the pixel electrodes; and light-emitting layers of each color provided between the common electrode and, respectively, each of the pixel electrodes, wherein one of each of the pixel electrodes and the common electrode is a cathode electrode and the other is an anode electrode and among the light-emitting layers of the at least three colors, a light-emitting layer of a color having a largest electron affinity extends in a state of being layered between the cathode electrode and each light-emitting layer of the other colors as well.

First claim

1 . A light-emitting element comprising:
pixel electrodes provided for individual subpixels of at least three colors; a common electrode provided facing each of the pixel electrodes; and light-emitting layers of each color provided between the common electrode and, respectively, each of the pixel electrodes, wherein one of each of the pixel electrodes and the common electrode is a cathode electrode and the other is an anode electrode and among the light-emitting layers of the at least three colors, a light-emitting layer of a color having a largest electron affinity extends in a state of being layered between the cathode electrode and each light-emitting layer of the other colors as well.

2 . The light-emitting element according to claim 1 ,
wherein, among the light-emitting layers of each color, a light-emitting layer of a color having a second largest electron affinity extends in a state of being layered between the light-emitting layer of the color having the largest electron affinity and a light-emitting layer of a remaining color among the light-emitting layers as well.

3 . The light-emitting element according to claim 1 ,
wherein the subpixels of at least three colors are a red subpixel, a green subpixel, and a blue subpixel and among a red light-emitting layer, a green light-emitting layer, and a blue light-emitting layer serving as the light-emitting layers of each color, the red light-emitting layer having the largest electron affinity extends in a state of being layered between the cathode electrode and the green light-emitting layer and the blue light-emitting layer of the other colors.

4 . The light-emitting element according to claim 2 ,
wherein the subpixels of at least three colors are a red subpixel, a green subpixel, and a blue subpixel and among a red light-emitting layer, a green light-emitting layer, and a blue light-emitting layer serving as the light-emitting layers of each color, the green light-emitting layer having the second largest electron affinity extends in a state of being layered between the red light-emitting layer having the largest electron affinity and the blue light-emitting layer of the remaining color as well.

5 . The light-emitting element according to claim 3 ,
wherein the red light-emitting layer, the green light-emitting layer, and the blue light-emitting layer each include quantum dot particles and in the light-emitting layers of each color being layered, a particle size of the quantum dot particles included in the light-emitting layers of each color positioned closer to the cathode electrode than the anode electrode is long.

6 . The light-emitting element according to claim 5 ,
wherein a light-emitting layer closest to the anode electrode among the light-emitting layers includes five or more layers of quantum dot particles.

7 . The light-emitting element according to claim 1 ,
wherein, among the light-emitting layers, a light-emitting layer formed on a patterned light-emitting layer differs in film thickness for each of the subpixels and among the light-emitting layers, a light-emitting layer of an upper layer of a subpixel in which light-emitting layers are layered has a film thickness thinner than a film thickness of a light-emitting layer of a subpixel in which light-emitting layers are not layered.

8 . The light-emitting element according to claim 1 ,
wherein the pixel electrodes of the anode electrode, the light-emitting layers of each color, and the common electrode of the cathode electrode are layered in this order and the light-emitting layers of each color being layered are layered between the anode electrode and the cathode electrode in ascending order of electron affinity.

9 . The light-emitting element according to any one of claim 1 ,
wherein the pixel electrodes of the cathode electrode, the light-emitting layers of each color, and the common electrode of the anode electrode are layered in this order and the light-emitting layers of each color being layered are layered between the cathode electrode and the anode electrode in descending order of electron affinity.

10 . The light-emitting element according to claim 1 ,
wherein an electron transport layer is provided between the light-emitting layers of each color and the cathode electrode and a hole transport layer is provided between the light-emitting layers of each color and the anode electrode.

11 . The light-emitting element according to claim 10 ,
wherein the electron affinity increases in the order of the electron transport layer, the red light-emitting layer, the green light-emitting layer, and the blue light-emitting layer.

12 . The light-emitting element according to claim 10 ,
wherein, among the light-emitting layers of each color being layered, a light-emitting layer of a color existing closer to the cathode electrode has a larger electron affinity than a light-emitting layer of a color existing closer to the hole transport layer.

13 . The light-emitting element according to claim 10 ,
wherein a difference between electron affinities of the hole transport layer and, among the light-emitting layers, a light-emitting layer in contact with the hole transport layer is greater than a difference in electron affinities between light-emitting layers being layered.

14 . The light-emitting element according to claim 10 ,
wherein a charge transport stopper layer having a larger band gap than those of the light-emitting layers of each color is provided between the light-emitting layers of each color and the electron transport layer.

15 . The light-emitting element according to claim 1 ,
wherein the light-emitting layers of each color contain a photosensitive resin.

16 . The light-emitting element according to claim 1 ,
wherein planar shapes of the light-emitting layers of each color differ from one another according to each color.

17 . The light-emitting element according to claim 10 ,
wherein a charge injection layer is provided between the light-emitting layers and the cathode electrode, or between the light-emitting layers and the anode electrode, or between the electron transport layer and the cathode electrode, or between the hole transport layer and the anode electrode.

18 . The light-emitting element according to claim 17 ,
wherein the electron transport layer, the hole transport layer, and the charge injection layer are each formed of a common material regardless of the subpixels of at least three colors.

19 . The light-emitting element according to claim 1 ,
wherein an insulating layer configured to partition the subpixels is provided between the subpixels and the light-emitting layer of the color having the largest electron affinity among the light-emitting layers of at least three colors is formed between the insulating layer and the common electrode as well.

20 . The light-emitting element according to claim 1 ,
wherein the light-emitting layer of the color having the largest electron affinity among the light-emitting layers of at least three colors is formed covering the subpixels of at least three colors.

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

22 . A manufacturing method of a light-emitting element including
pixel electrodes provided for individual subpixels of at least three colors, a common electrode provided facing each of the pixel electrodes, and light-emitting layers of each color provided between the common

Assignees

• Sharp Kk

Inventors

• Asaoka Yasushi
• Kamada Tsuyoshi
• Aomori Shigeru

Classifications

• H10K59/353

  characterised by the geometrical arrangement of the RGB subpixels · CPC title

• H10K2102/321

  Inverted OLED, i.e. having cathode between substrate and anode · CPC title

• H05B33/22

  characterised by the chemical or physical composition or the arrangement of auxiliary dielectric or reflective layers · CPC title

• H10K71/00

  Manufacture or treatment specially adapted for the organic devices covered by this subclass · CPC title

• H10K59/35

  comprising red-green-blue [RGB] subpixels · CPC title