Nanotechnology Now







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

International research partnership tricks the light fantastic March 2nd, 2015

UC research partnership explores how to best harness solar power March 2nd, 2015

Researchers turn unzipped nanotubes into possible alternative for platinum: Aerogel catalyst shows promise for fuel cells March 2nd, 2015

Important step towards quantum computing: Metals at atomic scale March 2nd, 2015

Chemistry

Chromium-Centered Cycloparaphenylene Rings as New Tools for Making Functionalized Nanocarbons February 24th, 2015

Stretch and relax! -- Losing 1 electron switches magnetism on in dichromium February 23rd, 2015

A straightforward, rapid and continuous method to protect MOF nanocrystals against water February 9th, 2015

Research shows benefits of silicon carbide for sensors in harsh environments: Advantages identified across industries February 9th, 2015

Announcements

International research partnership tricks the light fantastic March 2nd, 2015

UC research partnership explores how to best harness solar power March 2nd, 2015

Researchers turn unzipped nanotubes into possible alternative for platinum: Aerogel catalyst shows promise for fuel cells March 2nd, 2015

Important step towards quantum computing: Metals at atomic scale March 2nd, 2015

Tools

Forbidden quantum leaps possible with high-res spectroscopy March 2nd, 2015

International research partnership tricks the light fantastic March 2nd, 2015

Important step towards quantum computing: Metals at atomic scale March 2nd, 2015

Mass spectrometers with optimised hydrogen pumping March 1st, 2015

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 1999-2015 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE