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CN-122029936-A - Light-emitting element, display device, and method for manufacturing light-emitting element

CN122029936ACN 122029936 ACN122029936 ACN 122029936ACN-122029936-A

Abstract

The light emitting element includes a plurality of quantum dots (7) each including a core (9), and a shell (10) containing the core (9) and having a first dimension (S1) in a first direction (D1) and a second dimension (S2) larger than the first dimension (S1) in a second direction (D2) perpendicular to the first direction (D1). The band gap of the base material (8) is not less than the band gap of the shell (10).

Inventors

  • Yabuuchi haruta

Assignees

  • 夏普显示科技株式会社

Dates

Publication Date
20260512
Application Date
20231016

Claims (13)

  1. 1. A light-emitting element, comprising: anode and cathode, and A light emitting layer located between the anode and the cathode and including a plurality of quantum dots and a matrix material filling between the plurality of quantum dots, The plurality of quantum dots each include: Core, and A shell containing the core, having a first dimension in a first direction and a second dimension greater than the first dimension in a second direction perpendicular to the first direction, The band gap of the matrix material is greater than or equal to the band gap of the shell.
  2. 2. A light-emitting element according to claim 1, wherein, In the second direction, the shell has a first thickness on one side of the core and a second thickness on the other side of the core, The first thickness and the second thickness are each 7.5nm or more.
  3. 3. A light-emitting element according to claim 1 or 2, wherein, The plurality of quantum dots are respectively positioned at positions where the lamination direction of the anode, the light emitting layer, and the cathode coincides with the first direction, Two quantum dots of the plurality of quantum dots are located in the stacking direction with respect to each other.
  4. 4. A light-emitting element according to claim 3, wherein the case has a columnar shape extending in the second direction.
  5. 5. A light-emitting element according to claim 3, wherein the case is plate-shaped with an upper surface of the case facing the lamination direction.
  6. 6. The light-emitting element according to claim 1 or 2, wherein the plurality of quantum dots are irregularly arranged in units of 6 or less quantum dots in a plan view.
  7. 7. The light-emitting element according to claim 1 or 2, wherein an angle between a surface of the anode, the light-emitting layer, and the cathode perpendicular to the stacking direction and the second direction is 10 ° or more among at least 1 quantum dot among the plurality of quantum dots.
  8. 8. The light-emitting element according to any one of claims 1 to 7, wherein the second size is 2 times or more and 3 times or less than the first size.
  9. 9. The light-emitting element according to any one of claims 1 to 8, wherein the second dimension is 18nm or more.
  10. 10. The light-emitting element according to any one of claims 1 to 9, wherein a ratio of a volume of the core to a volume of the shell is 20% or less.
  11. 11. The light-emitting element according to any one of claims 1 to 10, wherein the base material is an inorganic base material.
  12. 12. A display device characterized in that it comprises the light-emitting element according to any one of claims 1 to 11.
  13. 13. A method for manufacturing a light-emitting element having a light-emitting layer including a plurality of quantum dots and a base material filling between the plurality of quantum dots, the method comprising: A step of applying a coating liquid containing the plurality of quantum dots and a precursor of the base material; A step of drying the coating liquid, and Firing the coating liquid to form the precursor as the base material, The plurality of quantum dots each include: Core, and A shell containing the core, having a first dimension in a first direction and a second dimension greater than the first dimension in a second direction perpendicular to the first direction.

Description

Light-emitting element, display device, and method for manufacturing light-emitting element Technical Field The present disclosure relates to a light emitting element, a display device, and a method of manufacturing the light emitting element. Background As disclosed in patent document 1, a technique is known in which the distance between quantum dots is increased by coating a metal oxide around the shell of the quantum dots, and the Forster Resonance Energy Transfer (FRET) is suppressed. Prior art literature Patent literature Patent document 1 U.S. patent application publication No. 2017/0271605 Disclosure of Invention Problems to be solved by the invention In patent document 1, when the distance between nuclei of the quantum dots is increased by a metal oxide coating or the like, the resistance of the light-emitting layer increases, and the light-emitting efficiency may be lowered. Solution for solving the problem The light-emitting element comprises an anode, a cathode, and a light-emitting layer, wherein the light-emitting layer is positioned between the anode and the cathode and comprises a plurality of quantum dots and a matrix material filled between the plurality of quantum dots, the plurality of quantum dots respectively comprise a core, and a shell, wherein the core is contained in the shell, the shell has a first size in a first direction and a second size which is larger than the first size in a second direction perpendicular to the first direction, and the band gap of the matrix material is more than the band gap of the shell. Effects of the invention According to one aspect of the present disclosure, a light-emitting element with high light-emitting efficiency can be realized. Drawings Fig. 1 is a cross-sectional view showing a schematic configuration of a light-emitting element according to embodiment 1 of the present disclosure. Fig. 2 is a perspective view illustrating the quantum dot shown in fig. 1. Fig. 3 is a perspective view of a first modification of the quantum dot. Fig. 4 is a perspective view of a second modification of the quantum dot. Fig. 5 is a perspective view of a third modification of the quantum dot. Fig. 6 is a graph illustrating the relationship between the ratio of the volume of the core to the volume of the shell, and the luminescence spectrum and the absorption spectrum of the quantum dot. FIG. 7 is a graph comparing the case where the material of the shell is the same as that of the medium with the case where the CBM of the medium is higher than that of the shell. Fig. 8 is a cross-sectional view showing an example of a light-emitting layer formation method according to embodiment 2 of the present disclosure. Fig. 9 is a cross-sectional view of a light-emitting layer and a top view of a plurality of quantum dots according to embodiment 2 of the present disclosure. Fig. 10 is a cross-sectional view of a light-emitting layer according to embodiment 3 of the present disclosure. Fig. 11 is an explanatory view of an angle between a plane perpendicular to the lamination direction and the second direction. Fig. 12 is a cross-sectional view showing an example of a schematic configuration of a display device according to embodiment 4. Detailed Description The manner in which the present disclosure is implemented is explained. For convenience of explanation, members having the same functions as those described above are given the same reference numerals, and the description will not be repeated. Embodiment 1 Fig. 1 is a cross-sectional view showing a schematic configuration of a light-emitting device 101 according to embodiment 1 of the present disclosure. The light-emitting element 101 includes an anode 1, a hole injection layer 2, a hole transport layer 3, a light-emitting layer 4, an electron transport layer 5, and a cathode 6. The light emitting layer 4 has a plurality of quantum dots 7 and a matrix material 8. The plurality of quantum dots 7 comprises a core 9 and a shell 10, respectively. The shell 10 contains the core 9. The shell 10 has a first dimension S1 in a first direction D1. The shell 10 has a second dimension S2 in a second direction D2. The second direction D2 is a direction perpendicular to the first direction D1. The second dimension S2 is larger than the first dimension S1. The first dimension S1 is a dimension in the first direction D1 from one outer end of the shell 10 to the other outer end of the shell 10, irrespective of the presence of the core 9. The second dimension S2, which is the same as the first dimension S1, is a dimension from one outer end of the shell 10 to the other outer end of the shell 10, irrespective of the presence of the core 9 in the second direction D2. The matrix material 8 fills in between the plurality of quantum dots 7. The band gap of the base material 8 is equal to or greater than the band gap of the shell 10. According to the light emitting element 101, the interval between the cores 9 of the plurality of quantum dots 7 can