Quantum dot and method of producing the same; and wavelength converting member, lighting member, back light unit, and display device using quantum dot

Patent metadata

Field	Value
Publication number	US-11845890-B2
Application number	US-202117405687-A
Country	US
Kind code	B2
Filing date	Aug 18, 2021
Priority date	Oct 12, 2017
Publication date	Dec 19, 2023
Grant date	Dec 19, 2023

Abstract

Provided is a Cd-free blue fluorescent quantum dot with a narrow fluorescence FWHM. The quantum dot does not contain cadmium and its fluorescence FWHM is 25 nm or less. The quantum dot is preferably a nanocrystal containing zinc and selenium or zinc and selenium and sulfur. Further, the quantum dot preferably has a core-shell structure in which the nanocrystal serves as a core and the surface of the core is coated with a shell.

First claim

The invention claimed is:

1. A quantum dot,
wherein the quantum dot:
does not contain cadmium,
has a fluorescence FWHM of 25 nm or less, and
is a nanocrystal containing:
zinc, selenium, and copper, or
zinc, selenium, sulfur, and copper; and

an amount of the copper contained in the nanocrystal is 100 ppm or less, excluding 0 ppm.

2. The quantum dot according to claim 1 , wherein the quantum dot has a core-shell structure in which:
the nanocrystal serves as a core and
a surface of the core is coated with a shell.

3. The quantum dot according to claim 1 ,
wherein a fluorescence wavelength of the quantum dot is 410 nm or more and 470 nm or less.

4. The quantum dot according to claim 1 ,
comprising ligands placed on the surface of the quantum dot.

5. The quantum dot according to claim 4 ,
wherein the ligands are comprised of at least one selected from aliphatic amines, phosphines, and aliphatic carboxylic acids.

6. A wavelength converting member comprising the quantum dot according to claim 1 .

7. A lighting member comprising the quantum dot according to claim 1 .

8. A back light unit comprising the quantum dot according to claim 1 .

9. A display device comprising the quantum dot according to claim 1 .

10. The quantum dot according to claim 1 ,
wherein the nanocrystals are formed by a metal exchange reaction between Cu and Zn.

11. The quantum dot according to claim 1 ,
wherein an amount of Cu remaining in the nanocrystal is 50 ppm or less.

12. The quantum dot according to claim 1 ,
wherein an amount of Cu remaining in the nanocrystal is 10 ppm or less.

Assignees

• Ns Mat Inc

Inventors

• Ogura Yuko
• Takamizuma Yuka
• Iida Kazunori
• Tsutsumi Emi
• Tanaka Masanori
• Nikata Soichiro

Classifications

• H10H20/851

  Wavelength conversion means · CPC title

• H10H20/8513

  having two or more wavelength conversion materials · CPC title

• C09K11/883 Primary

  with zinc or cadmium · CPC title

• C09K11/025

  non-luminescent particle coatings or suspension media · CPC title

• F21V9/30

  Elements containing photoluminescent material distinct from or spaced from the light source (shades F21V1/17; globes, bowls or cover glasses F21V3/08, F21V3/12; refractors F21V5/10; reflectors F21V7/26, F21V7/30; elements with provision for controlling the spectral properties or intensity F21V9/40) · CPC title