Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Small, Fast, and High Contrast

Annular dark field dynamic transmission electron microscopy (ADF-DTEM) can produce high-contrast images of catalyst nanoparticles with 15 ns temporal resolution (see picture). The contrast improvement provided by this technique enables imaging studies on the dynamics of heterogeneous catalysts at unprecedented spatial and temporal resolution.
Annular dark field dynamic transmission electron microscopy (ADF-DTEM) can produce high-contrast images of catalyst nanoparticles with 15 ns temporal resolution (see picture). The contrast improvement provided by this technique enables imaging studies on the dynamics of heterogeneous catalysts at unprecedented spatial and temporal resolution.

Abstract:
Imaging technique enables studies on the dynamics of nanocatalysts at unprecedented spatial and temporal resolution

Small, Fast, and High Contrast

Weinheim, Germany | Posted on June 2nd, 2010

Tiny catalyst materials may take part in a rich variety of very fast physical and chemical processes which can now be revealed more precisely thanks to a new imaging mode for dynamic transmission electron microscopes (DTEMs) developed by US scientists. "Our group has developed a dark-field imaging mode for DTEM that enables the highest combined spatial and temporal resolution imaging of nanoparticles achieved thus far", says Daniel Masiel of the University of California (Davis) and lead author of the work, which was published online in ChemPhysChem. According to Masiel, annular dark-field DTEM (ADF-DTEM) could, for the first time, enable direct time-resolved observation of processes such as nanowire growth, catalyst poisoning, and Ostwald ripening at nanosecond timescales.

A DTEM is a transmission electron microscope that has been modified to include a laser-driven photocathode that can produce a single intense pulse of electrons with a duration of only 15 ns. While the instrument has the potential to provide insight into nanoparticle catalyst dynamics by enabling direct imaging with high spatial and temporal resolution, the limited signal-to-background ratios attainable for dispersed nanoparticle samples have made such studies difficult to perform at optimal resolutions. To overcome these limitations, Masiel and co-workers have fabricated an annular objective lens aperture that permits images to be obtained with a threefold increase in the signal-to-background ratio. This annular dark-field imaging mode improves the contrast attainable in 15 ns-pulsed electron images and allows particles as small as 30 nm in diameter to be observed (see picture: single-shot pulsed dark-field DTEM image of tiny gold particles dispersed on a holey carbon film at 15 ns time resolution.)

Other techniques such as coherent diffractive imaging (using coherent X-rays) or in situ TEM offer direct imaging data but at the cost of either spatial or temporal resolution. This is not the case for ADF-DTEM, the researchers say—and they are sure that the new method will find applications in important fields of research: "By enabling the scientific community direct experimental insight into the behavior of nanometer-scale systems at nanosecond time intervals, ADF-DTEM promises to give engineers and scientists a powerful method for exploring systems that are at the core of some of the most crucial energy technologies of both today and tomorrow", Masiel says.

Author: Daniel Masiel, Ting Guo, University of California, Davis (USA), nanofast.ucdavis.edu/

Title: Time-Resolved Annular Dark Field Imaging of Catalyst Nanoparticles

ChemPhysChem 2010, 11, No. 10, Permalink to the article: dx.doi.org/10.1002/cphc.201000274

####

For more information, please click here

Copyright © ChemPhysChem

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

'Lasers rewired': Scientists find a new way to make nanowire lasers: Berkeley Lab, UC Berkeley scientists adapt next-gen solar cell materials for a different purpose February 12th, 2016

Breaking cell barriers with retractable protein nanoneedles: Adapting a bacterial structure, Wyss Institute researchers develop protein actuators that can mechanically puncture cells February 12th, 2016

Replacement of Toxic Antibacterial Agents Possible by Biocompatible Polymeric Nanocomposites February 12th, 2016

Properties of Polymeric Nanofibers Optimized to Treat Damaged Body Tissues February 12th, 2016

Chemistry

Chemical cages: New technique advances synthetic biology February 10th, 2016

Graphene decharging and molecular shielding February 8th, 2016

Scientists take key step toward custom-made nanoscale chemical factories: Berkeley Lab researchers part of team that creates new function in tiny protein shell structures February 6th, 2016

Discovery of the specific properties of graphite-based carbon materials February 6th, 2016

Announcements

Graphene leans on glass to advance electronics: Scientists' use of common glass to optimize graphene's electronic properties could improve technologies from flat screens to solar cells February 12th, 2016

Breaking cell barriers with retractable protein nanoneedles: Adapting a bacterial structure, Wyss Institute researchers develop protein actuators that can mechanically puncture cells February 12th, 2016

Replacement of Toxic Antibacterial Agents Possible by Biocompatible Polymeric Nanocomposites February 12th, 2016

Properties of Polymeric Nanofibers Optimized to Treat Damaged Body Tissues February 12th, 2016

Tools

Scientists take nanoparticle snapshots February 10th, 2016

Making sense of metallic glass February 9th, 2016

Chiral magnetic effect generates quantum current: Separating left- and right-handed particles in a semi-metallic material produces anomalously high conductivity February 8th, 2016

Metal oxide sandwiches: New option to manipulate properties of interfaces February 8th, 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