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

UK NANOSAFETY GROUP publishes 2nd Edition of guidance to support safe working with nanomaterials May 30th, 2016

Fast, stretchy circuits could yield new wave of wearable electronics May 30th, 2016

Automating DNA origami opens door to many new uses: Like 3-D printing did for larger objects, method makes it easy to build nanoparticles out of DNA May 30th, 2016

Simple attraction: Researchers control protein release from nanoparticles without encapsulation: U of T Engineering discovery stands to improve reliability and fabrication process for treatments to conditions such as spinal cord damage and stroke May 28th, 2016

Chemistry

Syracuse University chemists add color to chemical reactions: Chemists in the College of Arts and Sciences have come up with an innovative new way to visualize and monitor chemical reactions in real time May 19th, 2016

Technique improves the efficacy of fuel cells: Research demonstrates a new phase transition from metal to ionic conductor May 18th, 2016

Physicists measure van der Waals forces of individual atoms for the first time May 14th, 2016

Atomic force microscope reveals molecular ghosts: Mapping molecules with atomic precision expands toolbox for designing new catalytic reactions May 11th, 2016

Announcements

UK NANOSAFETY GROUP publishes 2nd Edition of guidance to support safe working with nanomaterials May 30th, 2016

Fast, stretchy circuits could yield new wave of wearable electronics May 30th, 2016

Automating DNA origami opens door to many new uses: Like 3-D printing did for larger objects, method makes it easy to build nanoparticles out of DNA May 30th, 2016

Simple attraction: Researchers control protein release from nanoparticles without encapsulation: U of T Engineering discovery stands to improve reliability and fabrication process for treatments to conditions such as spinal cord damage and stroke May 28th, 2016

Tools

Scientists illuminate a hidden regulator in gene transcription: New super-resolution technique visualizes important role of short-lived enzyme clusters May 27th, 2016

Light can 'heal' defects in new solar cell materials: Defects in some new electronic materials can be removed by making ions move under illumination May 24th, 2016

More light on cancer: Scientists created nanoparticles to highlight cancer cells May 21st, 2016

Nanotubes are beacons in cancer-imaging technique: Rice University researchers use spectral triangulation to pinpoint location of tumors May 21st, 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