Synthesis of uniform anisotropic nanoparticles

Patent metadata

Field	Value
Publication number	US-10518331-B2
Application number	US-201515324283-A
Country	US
Kind code	B2
Filing date	Jul 13, 2015
Priority date	Jul 11, 2014
Publication date	Dec 31, 2019
Grant date	Dec 31, 2019

Abstract

Methods of synthesizing various metal nanoparticle structures having high uniformity, using iterative reduction and oxidation conditions, is provided herein.

First claim

What is claimed is:

1. A method of preparing gold circular disk nanoparticle comprising
(a) admixing gold triangular prisms, a stabilizing agent, and an oxidizing agent in an aqueous solution to form a first intermediate;
(b) admixing the first intermediate, a gold salt, and a reducing agent, and optionally a base and halide salt, in an aqueous solution to form a second intermediate;
(c) admixing the second intermediate, a stabilizing agent, and oxidizing agent in an aqueous solution to form the gold circular disk nanoparticle; and
(d) optionally repeating steps (b) and (c) at least once to increase the uniformity of the resulting circular disk nanoparticles;

wherein the gold circular disk nanoparticles are formed in a yield of at least 70%.

2. The method of claim 1 , wherein the gold circular disk nanoparticles are formed in a yield of at least 90%.

3. The method of claim 1 , wherein the circular disk nanoparticles having uniformity as measured by a coefficient of variation (CV) of less than 30%.

4. The method of claim 3 , wherein the circular disk nanoparticles have a CV of 10% or less.

5. The method of claim 1 , wherein the oxidizing agent of steps (a) and (c) comprises HAuCl 4 .

6. The method of claim 5 , wherein the HAuCl 4 concentration correlates to the gold triangular prism edge length: at 8 μM for an edge length of 60 nm or less; at 10 μM for an edge length of 80 nm to 120 nm; at 12 μM for an edge length of 140nm; and at 13 μM for an edge length of 180 nm.

7. The method of claim 1 , wherein the stabilizing agent is selected from the group consisting of cetyltrimethylammonium bromide (CTAB), cetyltrimethylammonium chloride (CTAC), cetylpyridinium chloride (CPC), and a mixture thereof.

8. The method of claim 1 , wherein the gold salt comprises HAuCl 4 .

9. The method of claim 1 , wherein the reducing agent comprises ascorbic acid.

10. The method of claim 1 , wherein steps (b) and (c) are repeated at least twice.

11. The method of claim 1 , wherein the gold triangular prisms are prepared by
(1) admixing a stabilizing agent, an iodide salt, a gold salt, a base, a reducing agent, and nanoparticle seeds to form gold triangular prisms; and
(2) isolating the gold triangular prisms.

12. The method of claim 11 , wherein the concentration of nanoparticle seeds is 20 to 300 pM for a selected edge length of the gold triangular prism of 30 nm to 250 nm.

13. The method of claim 1 , wherein the isolating comprises adding a halide salt to the mixture resulting from step (1) and the concentration of the halide salt is selected in view of the edge length of the gold triangular prisms: 0.4M halide salt for triangular prisms with an edge length of 30 nm to 80 nm; 0.2M halide salt for triangular prisms with an edge length of 90 nm to 120 nm; 0.1M halide salt for triangular prisms with an edge length of 130 nm to 170 nm; and 0.05M halide salt for triangular prisms with an edge length of 180 nm to 250 nm.

14. A method of preparing uniform gold spherical nanoparticles comprising
(a) admixing gold nanorods, a stabilizing agent, and an oxidizing agent in an aqueous solution to form a first intermediate;
(b) admixing the first intermediate, a gold salt, and a reducing agent, and optionally a base and halide salt, in an aqueous solution to form a second intermediate;
(c) admixing the second intermediate, a stabilizing agent, and an oxidizing agent in an aqueous solution to form the gold spherical nanoparticles; and
(d) optionally repeating steps (b) and (c) at least once to increase the uniformity of the resulting gold spherical nanoparticles, as measured by a coefficient of variation (CV); wherein
(1) the method is performed in the absence of ethylene glycol, dimethylformamide, diethylene glycol, dimethylsulfoxide, toluene, tetrahydrofuran, hexane, octane, and oleic acid;
(2) the gold spherical nanoparticles are formed in a yield of at least 90%; and
(3) the gold spherical nanoparticles have a diameter of 1 nm to 99 nm.

15. The method of claim 14 , wherein the spherical nanoparticles have a CV of 3% or less.

16. The method of claim 14 , wherein the oxidizing agent of steps (a) and (c) comprises HAuCl 4 .

17. The method of claim 14 , wherein the gold salt comprises HAuCl 4 .

18. The method of claim 14 , wherein the reducing agent comprises ascorbic acid.

19. The method of claim 14 , wherein any one of step (a), (b), and (c) is performed for 0.5 hr to 2 hr.

20. The method of claim 19 , wherein each of step (a), (b), and (c) is performed for 0.5 hr to 6 hr.

Assignees

• Univ Northwestern

Inventors

• Mirkin Chad A
• Jones Matthew R
• O'Brien Matthew N

Classifications

• B22F1/0551

  Flake form nanoparticles · CPC title

• B22F1/054

  Nanosized particles · CPC title

• B22F1/065

  Spherical particles · CPC title

• B22F9/24 Primary

  starting from liquid metal compounds, e.g. solutions · CPC title

• B22F2001/0033

  Operations & Transport · mapped topic