Method to improve the morphology of core/shell quantum dots for highly luminescent nanostructures

Patent metadata

Field	Value
Publication number	US-10316250-B2
Application number	US-201715599848-A
Country	US
Kind code	B2
Filing date	May 19, 2017
Priority date	May 19, 2016
Publication date	Jun 11, 2019
Grant date	Jun 11, 2019

Abstract

Highly luminescent nanostructures, particularly highly luminescent quantum dots, comprising a nanocrystal core are provided. Also provided are methods of increasing the sphericity of nanostructures comprising subjecting nanocrystal cores to an acid etch step, an annealing step, or a combination of an acid etch step and an annealing step.

First claim

What is claimed is:

1. A population of nanostructures comprising a core comprising InP and at least one shell wherein the population of nanostructures deviate from a perfect sphere shape by between about 1% and about 8% and have a full width at half-maximum (FWHM) of between 10 nm and 60 nm.

2. The population of nanostructures of claim 1 , wherein the population of nanostructures displays a photoluminescence quantum yield between 70% and 99%.

3. The population of nanostructures of claim 1 , wherein the at least one shell comprises at least one of zinc, sulfur, selenium, or tellurium.

4. The population of nanostructures of claim 1 , wherein the population of nanostructures has a FWHM of between 10 nm and 50 nm.

5. The population of nanostructures of claim 1 , wherein the population of nanostructures deviate from a perfect sphere shape by between about 1% and about 4%.

6. The population of nanostructures of claim 1 , wherein the population of nanostructures displays a photoluminescence quantum yield between 75% and 99%.

7. The population of nanostructures of claim 1 , wherein the at least one shell comprises zinc and selenium or zinc and sulfur.

8. The population of nanostructures of claim 1 , wherein the population of nanostructures comprises two shells, wherein a first shell comprises zinc and selenium and a second shell comprises zinc and sulfur.

9. A method of producing the population of nanostructures of claim 1 comprising:
(a) contacting a nanocrystal core comprising InP with an organic acid, wherein the molar ratio of the nanocrystal core to the organic acid is between about 1:1 and about 1:1000; and
(b) heating (a) at a temperature between about 50° C. and about 250° C. to provide a nanostructure.

10. The method of claim 9 , wherein the organic acid is a carboxylic acid, a phosphonic acid, or a sulfonic acid.

11. The method of claim 9 , wherein the organic acid is selected from the group consisting of lauric acid, hexanoic acid, oleic acid, trifluoromethanesulfonic acid, octyl phosphonic acid, 2-ethylhexanoic acid, myristic acid, decanoic acid, palmitic acid, stearic acid, linoleic acid, and mixtures thereof.

12. The method of claim 9 , wherein the nanostructure produced is substantially spherical.

13. The method of claim 9 , wherein the nanostructure produced in (b) shows an increase in sphericity compared to the starting nanocrystal core in (a) of between about 1% and about 10%.

14. The method of claim 9 , further comprising:
(c) heating the nanostructure of (b) at a temperature between about 200° C. and 350° C. for between about 1 minute and 2 hours.

15. The method of claim 14 , further comprising:
(d) contacting the nanostructure of (c) with a shell material; and
(e) heating (d) at a temperature between about 200° C. and about 310° C.;
to provide a nanostructure with at least one shell.

16. The method of claim 9 , further comprising:
(d) contacting the nanostructure of (b) with a shell material; and
(e) heating (d) at a temperature between about 200° C. and about 310° C.;
to provide a nanostructure with at least one shell.

17. The method of claim 15 , wherein the shell material comprises at least two of a zinc source, a sulfur source, a selenium source, and a tellurium source.

18. The method of claim 9 , wherein the organic acid is lauric acid, the heating in (b) is conducted for between about 10 minutes and 50 minutes, and the heating in (b) is at a temperature between about 50° C. and about 100° C.

19. A method of producing the population of nanostructures of claim 1 comprising:
(a) heating a nanocrystal core comprising InP at a temperature between about 150° C. and 350° C. for between about 1 minute and 2 hours to provide a nanostructure;
(b) contacting the nanostructure of (a) with a shell material; and
(c) heating (b) at a temperature between about 200° C. and about 310° C.;
to provide a nanostructure with at least one shell.

20. The method of claim 19 , wherein the nanostructure produced in (c) is substantially spherical.

21. The method of claim 19 , wherein the nanostructure produced in (c) shows an increase in sphericity compared to the starting nanocrystal core in (a) of between about 1% and about 10%.

22. The method of claim 19 , wherein the shell material of (b) comprises at least two of a zinc source, a sulfur source, a selenium source, and a tellurium source.

Assignees

• Nanosys Inc

Inventors

• Guo Wenzhou
• Ippen Christian
• Hotz Charles
• BEELER Rose
• Lynch Jared
• Kan Shihai
• Truskier Jonathan
• Tu Minghu

Classifications

• C09K11/565

  with zinc cadmium · CPC title

• C09K11/70

  containing phosphorus · CPC title

• C09K11/883 Primary

  with zinc or cadmium · CPC title

• C09K11/02 Primary

  Use of particular materials as binders, particle coatings or suspension media therefor · CPC title

• B82Y40/00

  Manufacture or treatment of nanostructures · CPC title