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-11124703-B2
Application number	US-201816754578-A
Country	US
Kind code	B2
Filing date	Oct 12, 2018
Priority date	Oct 12, 2017
Publication date	Sep 21, 2021
Grant date	Sep 21, 2021

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 FWHIM is 25 nm or less. The quantum dot is preferably a na.nocrystal 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 method of producing a quantum dot having a core, the method comprising:
forming the core by:
synthesizing copper chalcogenide, as a precursor, from an organic copper compound or an inorganic copper compound, and an organic selenium compound;
performing metal exchange between copper in the copper chalcogenide precursor and zinc; and
synthesizing the core, which is free of cadmium and contains at least zinc and selenium,

wherein the organic selenium compound comprises a solution comprising selenium and a mixture of oleylamine and dodecanethiol, and
wherein selenium is dissolved in the mixture.

2. The method according to claim 1 , wherein the quantum dot is a nanocrystal containing zinc and selenium, or zinc and selenium and sulfur.

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

4. The method according to claim 1 , wherein ligands are placed on a surface of the quantum dot.

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

6. The method according to claim 1 , wherein the metal exchange reaction is performed at 180° C. or more and 280° C. or less.

7. The method according to claim 1 , wherein the copper chalcogenide is synthesized at a reaction temperature of 140° C. or more and 250° C. or less.

8. The method according to claim 2 , 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.

9. The method according to claim 1 , wherein an amount of copper remaining in the core is 100 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

• F21V7/30

  the coatings comprising photoluminescent substances · CPC title

• C09K11/883 Primary

  with zinc or cadmium · CPC title

• C09K11/88

  containing selenium, tellurium or unspecified chalcogen elements · CPC title