Method of preparing silver nanoparticles and silver nanorings

Patent metadata

Field	Value
Publication number	US-9745645-B2
Application number	US-201514632316-A
Country	US
Kind code	B2
Filing date	Feb 26, 2015
Priority date	Feb 26, 2015
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

A method of preparing silver nanoparticles, including silver nanorings. A zinc oxide thin film is formed initially by direct-current sputtering of a zinc target onto a substrate. A silver thin film is then formed by a similar sputtering technique, of a silver target onto the zinc oxide thin film. After that, the silver thin film is subject to an annealing treatment. The temperature, duration and atmosphere of the annealing treatment can be varied to control the average particle size, average distance between particles (density), particle size distribution of the silver nanoparticles. In at least one embodiment, silver nanoparticles of ring structure are produced.

First claim

The invention claimed is:

1. A method of forming silver nanoparticles, comprising:
forming a silver film on a zinc oxide film; and
annealing the silver film to form the silver nanoparticles from the silver film;
wherein the annealing is carried out at a temperature of 400-700° C. for a duration of 3-24 hours under an atmosphere of argon, nitrogen or air.

2. The method of claim 1 , further comprising forming the zinc oxide film by direct-current sputtering zinc onto a substrate under reactive oxygen plasma.

3. The method of claim 1 , further comprising isolating the silver nanoparticles from the zinc oxide film.

4. The method of claim 1 , wherein the silver film is formed by direct-current sputtering of silver on the zinc oxide film under argon plasma.

5. The method of claim 1 , wherein the silver nanoparticles formed by the annealing have an average particle size of 20-350 nm and the average size of the silver nanoparticles increases with the temperature.

6. The method of claim 1 , wherein the silver nanoparticles formed by the annealing have an average distance between particles of 350-3500 nm and the average distance between particles decreases with the temperature.

7. A method of forming silver nanoparticles, comprising:
forming a silver film on a zinc oxide film; and
annealing the silver film to form the silver nanoparticles from the silver film;
wherein the annealing is carried out at 500-700° C. for 5-7 hours under nitrogen to form silver nanoparticles of ring structure having an inner diameter of 250-600 nm, an outer diameter of 1000-1200 nm and a ring wall thickness of 70-90 nm.

Assignees

• Univ King Fahd Pet & Minerals

Inventors

• DRMOSH Qasem Ahmed
• Hossain Mohammad Kamal
• Tabet Nouar Amor

Classifications

• B22F1/056

  Submicron particles having a size above 100 nm up to 300 nm · CPC title

• B22F1/0553

  Complex form nanoparticles, e.g. prism, pyramid, octahedron · CPC title

• B22F1/052

  characterised by a mixture of particles of different sizes or by the particle size distribution · CPC title

• B22F1/054

  Nanosized particles · CPC title

• C22C5/06 Primary

  Alloys based on silver · CPC title