Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

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

Searching for errors in the quantum world September 21st, 2018

Viral RNA sensing: Optical detection of picomolar concentrations of RNA using switches in plasmonic chirality September 21st, 2018

UT engineers develop first method for controlling nanomotors: Breakthrough for nanotechnology as UT engineers develop first method for switching the mechanical motion of nanomotors September 21st, 2018

Nanobiotix: Update on Head and Neck Phase I/II Trial with NBTXR3 and Other program data presented at ImmunoRad 2018 September 20th, 2018

Chemistry

Halas wins American Chemical Society Award in Colloid Chemistry: Rice University nanophotonics pioneer honored for colloid research September 18th, 2018

How a tetrahedral substance can be more symmetrical than a spherical atom: A new type of symmetry September 14th, 2018

Terahertz spectroscopy enters the single-molecule regime September 7th, 2018

Peering into private life of atomic clusters -- using the world's tiniest test tubes September 6th, 2018

Govt.-Legislation/Regulation/Funding/Policy

UT engineers develop first method for controlling nanomotors: Breakthrough for nanotechnology as UT engineers develop first method for switching the mechanical motion of nanomotors September 21st, 2018

Researchers develop microbubble scrubber to destroy dangerous biofilms September 19th, 2018

Researchers managed to prevent the disappearing of quantum information September 14th, 2018

New photonic chip promises more robust quantum computers September 14th, 2018

Possible Futures

Searching for errors in the quantum world September 21st, 2018

Viral RNA sensing: Optical detection of picomolar concentrations of RNA using switches in plasmonic chirality September 21st, 2018

UT engineers develop first method for controlling nanomotors: Breakthrough for nanotechnology as UT engineers develop first method for switching the mechanical motion of nanomotors September 21st, 2018

Leti Announces EU Project to Develop Powerful, Inexpensive Sensors with Photonic Integrated Circuits: REDFINCH Members Initially Targeting Applications for Gas Detection and Analysis For Refineries & Petrochemical Industry and Protein Analysis for Dairy Industry September 19th, 2018

Academic/Education

The Institute of Applied Physics at the University of Tsukuba near Tokyo in Japan uses Deben's ARM2 detector to better understand catalytic reaction mechanisms June 27th, 2018

Powering the 21st Century with Integrated Photonics: UCSB-Led Team Selected for Demonstration of a Novel Waveguide Platform Which is Transparent Throughout the MWIR and LWIR Spectral Bands June 19th, 2018

SUNY Poly Professor Eric Lifshin Selected for ‘Fellow of the Microanalysis Society’ Position for Significant Contributions to Microanalysis June 13th, 2018

Grand Opening of UC Irvine Materials Research Institute (IMRI) to Spotlight JEOL Center for Nanoscale Solutions: Renowned Materials Scientists to Present at the 1st International Symposium on Advanced Microscopy and Spectroscopy (ISAMS) April 18th, 2018

Announcements

Searching for errors in the quantum world September 21st, 2018

Viral RNA sensing: Optical detection of picomolar concentrations of RNA using switches in plasmonic chirality September 21st, 2018

UT engineers develop first method for controlling nanomotors: Breakthrough for nanotechnology as UT engineers develop first method for switching the mechanical motion of nanomotors September 21st, 2018

Nanobiotix: Update on Head and Neck Phase I/II Trial with NBTXR3 and Other program data presented at ImmunoRad 2018 September 20th, 2018

Homeland Security

Northwestern researchers achieve unprecedented control of polymer grids: Materials could find applications in water purification, solar energy storage, body armor June 22nd, 2018

Powering the 21st Century with Integrated Photonics: UCSB-Led Team Selected for Demonstration of a Novel Waveguide Platform Which is Transparent Throughout the MWIR and LWIR Spectral Bands June 19th, 2018

Squeezing light at the nanoscale: Ultra-confined light could detect harmful molecules June 17th, 2018

The dispute about the origins of terahertz photoresponse in graphene results in a draw April 26th, 2018

Military

Ultracold atoms used to verify 1963 prediction about 1D electrons: Rice University, University of Geneva study focuses on theory that's increasingly relevant to chipmakers September 5th, 2018

Neutrophil nanosponges soak up proteins that promote rheumatoid arthritis September 3rd, 2018

Virginia Tech researchers develop novel process to 3D print one of the strongest materials on Earth August 23rd, 2018

Biomimetic micro/nanoscale fiber reinforced composites August 10th, 2018

Environment

Silver nanoparticles are toxic for aquatic organisms: A research team at the UPV/EHU-University of the Basque Country has analysed how zebrafish are affected in the long term by exposure to silver particles September 19th, 2018

Carbon nanodots do an ultrafine job with in vitro lung tissue: New experiments highlight the role of charge and size when it comes to carbon nanodots that mimic the effect of nanoscale pollution particles on the human lung. September 12th, 2018

A human enzyme can biodegrade graphene August 28th, 2018

Large scale preparation method of high quality SWNT sponges August 24th, 2018

Industrial

Graphene nanotubes outperform ammonium salts and carbon black in PU applications September 11th, 2018

Carbon in color: First-ever colored thin films of nanotubes created: A method developed at Aalto University, Finland, can produce large quantities of pristine single-walled carbon nanotubes in select shades of the rainbow; the secret is a fine-tuned fabrication process -- and a s August 29th, 2018

Connecting the (Nano) Dots: NIST Says Big-Picture Thinking Can Advance Nanoparticle Manufacturing August 22nd, 2018

A colossal breakthrough for topological spintronics: BiSb expands the potential of topological insulators for ultra-low-power electronic devices August 2nd, 2018

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



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project