Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Wavelength-Dependent Shapeshifting: Plasmon-Mediated Growth Control

Abstract:
Methods which allow predictable and reproducible control over the shape and defect structures of nanoparticles are a sought-after ideal in research on nanoparticle synthesis. Realising this ideal for silver nanoparticles is one step closer with the discovery that the localised surface plasmon resonance feature observed for nanoscale metals - the collective oscillation of their electrons caused by incident light - can be used to predictably direct the growth of silver nanocrystals.

Wavelength-Dependent Shapeshifting: Plasmon-Mediated Growth Control

Germany | Posted on January 10th, 2013

Such plasmon-mediated growth allows control over the size and shape of the crystals by controlling the wavelength of light incident on the sample. The underlying mechanism is based on silver redox chemistry: excitation of the plasmon in an aqueous citrate solution catalyses the reduction of silver ions, the speed of which influences the dominant facets (and hence the shape) of the growing crystals. In this way, longer excitation wavelengths can be applied to produce longer edge lengths. The corresponding oxidation of seed particles causes their dissolution, increasing the bulk concentration of silver ions.

Mirkin and co-workers have refined this technique to generate twinned silver nanocrystals by controlling the defects within the crystal structure. They discovered that irradiation at higher energies increases the number of twin boundaries during growth. By adjusting the wavelength from 400 to 500 nm, bipyramids or cubes with different types of twin boundaries could be selectively produced.

More specifically, longer excitation wavelengths (500 nm) reduce silver ions more slowly, producing monodisperse planar-twinned nanostructures (right bipyramids); shorter excitation wavelengths (400 nm) increase the silver ion reduction rate, increasing the growth speed and hence producing crystals with a higher number of defects, leading to twinned structures. Using the intermediate wavelength of 450 nm, silver nanocubes with multiple twin boundaries could be selectively generated.

This plasmon-mediated shape control could also be extended to longer wavelengths, which were tuned to produce silver nanorods with controllable aspect ratios.

The challenge is now to develop this method for other nanoscale species with plasmon resonances.

####

For more information, please click here

Copyright © Wiley-VCH Materials Science Journals

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 Links

Link to the original paper on Wiley Online Library:

Related News Press

News and information

Nano Ruffles in Brain Matter: Freiburg researchers decipher the role of nanostructures around brain cells in central nervous system function October 31st, 2014

Gold nanoparticle chains confine light to the nanoscale October 31st, 2014

'Nanomotor lithography' answers call for affordable, simpler device manufacturing October 31st, 2014

Device invented at Johns Hopkins provides up-close look at cancer on the move: Microscopic view of metastasis could give insight about how to keep cancer in check October 31st, 2014

Amorphous Coordination Polymer Particles as alternative to classical nanoplatforms for nanomedicine October 30th, 2014

Chemistry

First Observation of Electronic Structure in Ag-Rh Alloy Nanoparticles Having Hydrogen Absorbing: Storage Property –Attempting to solve the mystery of why Ag-Rh alloy nanoparticles have a similar property to Pd– October 30th, 2014

A new cheap and efficient method to improve SERS, an ultra-sensitive chemical detection technique October 28th, 2014

Iranian, Malaysian Scientists Study Nanophotocatalysts for Water Purification October 23rd, 2014

Discoveries

Nano Ruffles in Brain Matter: Freiburg researchers decipher the role of nanostructures around brain cells in central nervous system function October 31st, 2014

Gold nanoparticle chains confine light to the nanoscale October 31st, 2014

'Nanomotor lithography' answers call for affordable, simpler device manufacturing October 31st, 2014

Device invented at Johns Hopkins provides up-close look at cancer on the move: Microscopic view of metastasis could give insight about how to keep cancer in check October 31st, 2014

Materials/Metamaterials

Production of Biocompatible Polymers in Iran October 30th, 2014

New solar power material converts 90 percent of captured light into heat: SunShot Project aims to make solar cost competitive October 29th, 2014

Watching the hidden life of materials: Ultrafast electron diffraction experiments open a new window on the microscopic world October 27th, 2014

Polymeric Scaffold Recreates Bladder Tissue October 27th, 2014

Announcements

Nano Ruffles in Brain Matter: Freiburg researchers decipher the role of nanostructures around brain cells in central nervous system function October 31st, 2014

Gold nanoparticle chains confine light to the nanoscale October 31st, 2014

'Nanomotor lithography' answers call for affordable, simpler device manufacturing October 31st, 2014

Device invented at Johns Hopkins provides up-close look at cancer on the move: Microscopic view of metastasis could give insight about how to keep cancer in check October 31st, 2014

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







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE