Method of preparing quantum dot, optical member comprising quantum dot, and apparatus comprising quantum dot

Patent metadata

Field	Value
Publication number	US-11649402-B2
Application number	US-202017034861-A
Country	US
Kind code	B2
Filing date	Sep 28, 2020
Priority date	Jan 10, 2020
Publication date	May 16, 2023
Grant date	May 16, 2023

Abstract

A method of preparing a quantum dot, a quantum dot prepared by the method, an optical member including the quantum dot, and an apparatus including the quantum dot. The quantum dot may include: a core including a III-V compound; a first shell surrounding the core and including ZnSe; a second shell surrounding the first shell and including ZnSe1-xSx, wherein x may be a real number greater than 0 and smaller than 1; and a third shell surrounding the second shell and including ZnS. The method may include: forming the first shell from a first material including zinc and a second material including selenium in a solution; forming the second shell by adding to the solution a third material including zinc and a fourth material including selenium and sulfur; and forming the third shell by adding to the solution a fifth material including zinc.

First claim

What is claimed is:

1. A method of preparing a quantum dot, wherein the quantum dot comprises:
a core comprising a III-V compound;
a first shell surrounding the core and comprising ZnSe;
a second shell surrounding the first shell and comprising ZnSe 1-x S x , wherein x is a real number greater than 0 and smaller than 1; and
a third shell surrounding the second shell and comprising ZnS, the method comprising:
forming the first shell from a first solution comprising a first material comprising zinc and a second material comprising selenium;
forming the second shell by adding a third material comprising zinc and a fourth material comprising selenium and sulfur to the first solution to form a second solution; and
forming the third shell by adding a fifth material comprising zinc to the second solution, wherein
the forming of the first shell comprises act (a) of adding the first material and act (b) of adding the second material,
the forming of the second shell comprises act (c) of adding the third material and act (d) of adding the fourth material, and
wherein the fourth material is about 0.1:1 to about 0.0005:1 in molar ratio of the selenium to the sulfur.

2. The method of claim 1 , wherein the forming of the first shell comprises performing each of act (a) and act (b) at least two times.

3. The method of claim 1 , wherein the forming of the first shell comprises sequentially conducting following acts:
act (a1) of adding the first material;
act (b1) of adding the second material;
act (a2) of adding the first material; and
act (b2) of adding the second material,
wherein as act (a1), act (b1), act (a2), and act (b2) are sequentially performed, a reaction temperature gradually increases.

4. The method of claim 1 , wherein the forming of the second shell comprises repeatedly performing each of act (c) and act (d) at least two times.

5. The method of claim 1 , wherein the forming of the second shell comprises sequentially conducting following acts:
act (c1) of adding the third material;
act (d1) of adding the fourth material;
act (c2) of adding the third material; and
act (d2) of adding the fourth material,
wherein as act (c1), act (d1), act (c2), and act (d2) are sequentially performed, a reaction temperature gradually increases.

6. The method of claim 1 , wherein the first material and the third material each comprise zinc stearate.

7. The method of claim 1 , wherein
the second material comprises selenium powder, and
the fourth material comprises selenium powder and sulfur powder.

8. The method of claim 1 , wherein selenium in ZnSe 1-x S x comprised in the second shell is greater in content toward the first shell and lower in content toward the third shell, thus forming a concentration gradient.

9. The method of claim 1 , wherein the III-V compound is selected from GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InGaP, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, and a combination thereof.

10. The method of claim 1 , wherein the method further comprises forming the core comprising the III-V compound from a Group III precursor and a Group V precursor.

11. The method of claim 1 , wherein the forming of the third shell is performed at a temperature lower than a temperature in the forming of the second shell.

12. The method of claim 1 , wherein the fifth material comprises zinc acetate.

13. The method of claim 1 , wherein the first solution further comprises a zinc precursor and an organic ligand.

14. A quantum dot prepared according to the method of claim 1 .

15. An optical member comprising the quantum dot of claim 14 .

16. The optical member of claim 15 , wherein the optical member is a color-conversion member.

17. An apparatus comprising the quantum dot of claim 14 .

18. The apparatus of claim 17 comprising:
a light source to emit light; and
a color-conversion member located on a pathway of light emitted from the light source,
wherein the color-conversion member comprises the quantum dot.

19. The apparatus of claim 18 , wherein the light source is an organic light-emitting device (OLED) or a light-emitting diode (LED), and
the light source is to emit blue light having a maximum emission wavelength in a range of about 400 nanometers (nm) to about 490 nm.

20. The apparatus of claim 19 , wherein at least one portion of the color-conversion member comprises the quantum dot, and the at least one portion is to absorb the blue light emitted from the light source and to emit visible light other than blue light.

Assignees

• Samsung Display Co Ltd
• Univ Hannam Inst Ind Acad Coop

Inventors

• Ko Yunhyuk
• Lee Kwangsup
• Prem Prabhakaran
• Lee Changhee
• Kim Gyeongju
• Choi Sinil

Classifications

• H10H20/855

  Optical field-shaping means, e.g. lenses · CPC title

• H10H20/824

  comprising only Group III-V materials, e.g. GaP · CPC title

• H10H20/823

  comprising only Group II-VI materials, e.g. ZnO · CPC title

• H10H20/812

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

• H10H20/8512

  Wavelength conversion materials · CPC title