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

Ultrathin, flat lens resolves chirality and color: Multifunctional lens could replace bulky, expensive machines June 25th, 2016

Nanotechnology and math deliver two-in-one punch for cancer therapy resistance June 24th, 2016

Researchers discover new chemical sensing technique: Technique allows sharper detail -- and more information -- with near infrared light June 24th, 2016

Soft decoupling of organic molecules on metal June 23rd, 2016

Chemistry

Quantum calculations broaden the understanding of crystal catalysts: Quantum mechanics and a supercomputer help scientists to identify the position of atoms on the surface of rutile June 22nd, 2016

Droplets finally all the same size -- in a nanodroplet library June 20th, 2016

Nano 'hall of mirrors' causes molecules to mix with light June 14th, 2016

Weird, water-oozing material could help quench thirst: Nanorods' behavior first theorized 20 years ago, but not seen until now June 13th, 2016

Govt.-Legislation/Regulation/Funding/Policy

Ultrathin, flat lens resolves chirality and color: Multifunctional lens could replace bulky, expensive machines June 25th, 2016

Particle zoo in a quantum computer: First experimental quantum simulation of particle physics phenomena June 23rd, 2016

New electron microscope method detects atomic-scale magnetism June 22nd, 2016

Tailored DNA shifts electrons into the 'fast lane': DNA nanowire improved by altering sequences June 22nd, 2016

Possible Futures

Nanotechnology and math deliver two-in-one punch for cancer therapy resistance June 24th, 2016

Researchers discover new chemical sensing technique: Technique allows sharper detail -- and more information -- with near infrared light June 24th, 2016

GraphExeter illuminates bright new future for flexible lighting devices June 23rd, 2016

Soft decoupling of organic molecules on metal June 23rd, 2016

Academic/Education

JPK’s NanoWizard® AFM and ForceRobot® systems are being used in the field of medical diagnostics in the Supersensitive Molecular Layer Laboratory of POSTECH in Korea June 21st, 2016

Weizmann Institute of Science Presents: Weizmann Wonder Wander - 4G - is Online June 21st, 2016

NanoLabNL boosts quality of research facilities as Dutch Toekomstfonds invests firmly June 10th, 2016

The Institute for Transfusion Medicine at the University Hospital of Duisburg-Essen in Germany uses the ZetaView from Particle Metrix to quantify extracellular vesicles June 7th, 2016

Announcements

Ultrathin, flat lens resolves chirality and color: Multifunctional lens could replace bulky, expensive machines June 25th, 2016

Nanotechnology and math deliver two-in-one punch for cancer therapy resistance June 24th, 2016

Researchers discover new chemical sensing technique: Technique allows sharper detail -- and more information -- with near infrared light June 24th, 2016

Soft decoupling of organic molecules on metal June 23rd, 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

Ultrathin, flat lens resolves chirality and color: Multifunctional lens could replace bulky, expensive machines June 25th, 2016

Scientists engineer tunable DNA for electronics applications June 21st, 2016

Marrying superconductors, lasers, and Bose-Einstein condensates: Chapman University Institute for Quantum Studies (IQS) member Yutaka Shikano, Ph.D., recently had research published in Scientific Reports June 20th, 2016

A new trick for controlling emission direction in microlasers June 20th, 2016

Environment

The use of nanoparticles and bioremediation to decontaminate polluted soils June 14th, 2016

UQ research accelerates next-generation ultra-precise sensing technology June 10th, 2016

VentureLab nanotechnology startup wins TechConnect Innovation Award June 2nd, 2016

The next generation of carbon monoxide nanosensors May 26th, 2016

Industrial

Industrial Nanotech, Inc. Signs Agreement With and Receives First Purchase Order from Major New Customer in China June 6th, 2016

GLOBALFOUNDRIES to Expand Presence in China with 300mm Fab in Chongqing: Company plans new manufacturing facility and additional design capabilities to serve customers in China May 31st, 2016

Finding a new formula for concrete: Researchers look to bones and shells as blueprints for stronger, more durable concrete May 26th, 2016

Solliance realizes first up-scaled Perovskite based PV modules with 10% efficiency: Holst Centre, imec and ECN pave the road to upscaling Perovskite PV modules May 10th, 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