Nanotechnology Now

Our NanoNews Digest Sponsors


Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Study Improves Understanding of Method for Creating Multi-Metal Nanoparticles

This diagram shows how researchers created the core/shell nanoparticles, and alloy nanoparticles, from gold and silver.
This diagram shows how researchers created the core/shell nanoparticles, and alloy nanoparticles, from gold and silver.

Abstract:
A new study from researchers at North Carolina State University sheds light on how a technique that is commonly used for making single-metal nanoparticles can be extended to create nanoparticles consisting of two metals - and that have tunable properties. The study also provides insight into the optical properties of some of these nanoparticles.

Study Improves Understanding of Method for Creating Multi-Metal Nanoparticles

Raleigh, NC | Posted on December 16th, 2010

Tuning the optical properties of nanoparticles is of interest for applications such as security technology, and for use in making chemical reactions more efficient - which has multiple industrial and environmental applications.

The researchers created core/shell nanoparticles with a gold core and silver shell, as well as alloy nanoparticles, which mix the gold and silver. The researchers also characterized the optical properties of these nanoparticles. "Silver and gold have unique optical properties arising from their specific interactions with the electric field of light," says Dr. Joe Tracy, an assistant professor of materials science and engineering at NC State and co-author of a paper describing the study. "By manipulating the ratio of the metals, and whether the nanoparticles have core/shell or alloy structures, we can alter their optical properties with control."

The researchers synthesized the nanoparticles using a technique called "digestive ripening." The technique has been used to create single-metal particles for approximately a decade, but there have been limited studies of core/shell and alloy nanoparticles created using digestive ripening. However, the comprehensive nature of this study may make it more common.

"This study, along with related work by others, shows that digestive ripening is a viable method for creating multi-component metal nanoparticles. We used gold and silver, but the same principles would likely apply to other metals," Tracy says. "Our detailed evaluation of this synthetic approach should help other researchers explore other kinds of binary metal nanoparticles."

Digestive ripening relies on the use of ligands, which are small organic molecules with parts that bond directly to metals. The ligands are usually anchored to the metal cores of the nanoparticles and prevent the nanoparticles from clumping together, which allows them to be suspended in solution. Digestive ripening occurs when the ligands are able to transport metal atoms from the core of one nanoparticle to another - resulting in a more homogenous size distribution among the nanoparticles.

The researchers used digestive ripening to create a solution of gold nanoparticles of similar size. When they introduced silver acetate into the solution, the ligands transported silver atoms to the surfaces of the gold nanoparticles, resulting in nanoparticles with gold cores and silver shells.

Researchers then transferred the nanoparticles into a second solution, containing a different ligand. Heating this second solution to 250 degrees Celsius caused the metals to diffuse into each other - creating nanoparticles made of a gold-silver alloy.

The researchers also created gold-silver alloy nanoparticles by skipping the shell-creation step, introducing silver acetate into the second solution, and raising the temperature to 250 degrees Celsius. This "shortcut" method has the benefit of simplifying control over the gold-to-silver ratio of the alloy.

The paper, "Synthesis of Au(core)/Ag(shell) Nanoparticles and their Conversion to AuAg Alloy Nanoparticles," was published online Dec. 13 by the journal Small. The research was funded by the National Science Foundation and NC State. The lead author of the paper is Matthew Shore, who was an undergraduate at NC State when the research was done. Co-authors include Tracy, NC State Ph.D. student Aaron Johnston-Peck, former NC State postdoc Dr. Junwei Wang, and University of North Carolina at Chapel Hill assistant professor Dr. Amy Oldenburg.

NC State's Department of Materials Science and Engineering is part of the university's College of Engineering.

Note to Editors: The study abstract follows.

"Synthesis of Au(core)/Ag(shell) Nanoparticles and their Conversion to AuAg Alloy Nanoparticles"

Authors: Matthew S. Shore, Junwei Wang, Aaron C. Johnston-Peck, Joseph B.
Tracy, North Carolina State University; Amy L. Oldenburg, University of North Carolina at Chapel Hill

Published: online Dec. 13, in Small

Abstract: Au(core)/Ag(shell) and AuAg alloy nanoparticles are synthesized with stoichiometric control through digestive ripening, a potentially general approach for synthesizing core/shell and alloy nanoparticles. AuAg alloy nanoparticles are obtained by annealing Au(core)/Ag(shell) nanoparticles. These bimetal nanoparticles have a tunable surface plasmon resonance absorbance and of interest for use in catalysis and as taggants for security applications.

####

For more information, please click here

Contacts:
Matt Shipman
News Services
919.515.6386

Dr. Joe Tracy
919.515.2623

Copyright © North Carolina State University

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Cooling graphene-based film close to pilot-scale production April 30th, 2016

Personal cooling units on the horizon April 29th, 2016

Exploring phosphorene, a promising new material April 29th, 2016

The Translational Research Center at the University Hospital of Erlangen in Germany uses the ZetaView from Particle Metrix to quantify extracellular vesicles such as exosomes April 28th, 2016

Chemistry

Adding some salt to the recipe for energy storage materials: Researchers use common table salt as growth template April 22nd, 2016

NRL reveals novel uniform coating process of p-ALD April 21st, 2016

Team builds first quantum cascade laser on silicon: Eliminates the need for an external light source for mid-infrared silicon photonic devices or photonic circuits April 21st, 2016

McMaster researchers achieve a first by coaxing molecules into assembling themselves: Major advance creates the potential for useful new materials April 21st, 2016

Govt.-Legislation/Regulation/Funding/Policy

Cooling graphene-based film close to pilot-scale production April 30th, 2016

Personal cooling units on the horizon April 29th, 2016

Exploring phosphorene, a promising new material April 29th, 2016

Nanoparticles hold promise as double-edged sword against genital herpes April 28th, 2016

Possible Futures

Cooling graphene-based film close to pilot-scale production April 30th, 2016

Personal cooling units on the horizon April 29th, 2016

Exploring phosphorene, a promising new material April 29th, 2016

Hybrid nanoantennas -- next-generation platform for ultradense data recording April 28th, 2016

Academic/Education

JPK reports on the use of a NanoWizard AFM system at the University of Kaiserslautern to study the interaction of bacteria with microstructured surfaces April 28th, 2016

The Ottawa Hospital Research Institute uses the ZetaView from Particle Metrix to study membrane microparticles as potential biomarkers for underlying diseases April 12th, 2016

FEI Partners with Five Pharmaceutical Companies, the Medical Research Council and the University of Cambridge to form Cryo-EM Research Consortium April 5th, 2016

SUNY Poly, in Collaboration with the George Washington School of Medicine and Health Sciences and Stony Brook University, Demonstrates Pioneering Method to Visualize and Identify Engineered Nanoparticles in Tissue March 25th, 2016

Announcements

Cooling graphene-based film close to pilot-scale production April 30th, 2016

Personal cooling units on the horizon April 29th, 2016

Exploring phosphorene, a promising new material April 29th, 2016

The Translational Research Center at the University Hospital of Erlangen in Germany uses the ZetaView from Particle Metrix to quantify extracellular vesicles such as exosomes April 28th, 2016

Homeland Security

Team builds first quantum cascade laser on silicon: Eliminates the need for an external light source for mid-infrared silicon photonic devices or photonic circuits April 21st, 2016

Nanoporous material's strange "breathing" behavior April 7th, 2016

Sniffing out a dangerous vapor: University of Utah engineers develop material that can sense fuel leaks and fuel-based explosives March 28th, 2016

Detecting and identifying explosives with single test December 10th, 2015

Military

Nanograft seeded with 3 cell types promotes blood vessel formation to speed wound healing April 27th, 2016

The light stuff: A brand-new way to produce electron spin currents - Colorado State University physicists are the first to demonstrate using non-polarized light to produce a spin voltage in a metal April 26th, 2016

NRL reveals novel uniform coating process of p-ALD April 21st, 2016

Team builds first quantum cascade laser on silicon: Eliminates the need for an external light source for mid-infrared silicon photonic devices or photonic circuits April 21st, 2016

Environment

Team builds first quantum cascade laser on silicon: Eliminates the need for an external light source for mid-infrared silicon photonic devices or photonic circuits April 21st, 2016

Atomically thin sensor detects harmful air pollution in the home April 18th, 2016

Catalyst could make production of key chemical more eco-friendly April 10th, 2016

Nanoporous material's strange "breathing" behavior April 7th, 2016

Industrial

Novel anti-biofilm nano coating developed at Ben-Gurion U.: Offers significant anti-adhesive potential for a variety of medical and industrial applications April 25th, 2016

Model aids efforts to reduce cost of carbon nanostructures for industry, research April 5th, 2016

Molecular-scale ALD discovery could have industrial-sized impact: New atomic layer deposition technique reduces waste March 31st, 2016

Transparent wood could one day help brighten homes and buildings March 31st, 2016

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







Car Brands
Buy website traffic