Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New technique uses electrons to map nanoparticle atomic structures

07.05.2012
Accessibility of electron microscopes could make technique standard practice

With dimensions measuring billionths of a meter, nanoparticles are way too small to see with the naked eye. Yet it is becoming possible for today's scientists not only to see them, but also to look inside at how the atoms are arranged in three dimensions using a technique called nanocrystallography.

Trouble is, the powerful machines that make this possible, such as x-ray synchrotrons, are only available at a handful of facilities around the world. The U.S. Department of Energy's Brookhaven National Laboratory is one of them — home to the National Synchrotron Light Source (NSLS) and future NSLS-II, where scientists are using very bright, intense x-ray beams to explore the small-scale structure of new materials for energy applications, medicine, and more.

But a Brookhaven/Columbia Engineering School team of scientists, in collaboration with researchers at DOE's Argonne National Laboratory (ANL) and Northwestern University, has also been working to develop nanocrystallography techniques that can be used in more ordinary science settings. They have shown how a powerful method called atomic pair distribution function (PDF) analysis — which normally requires synchrotron x-rays or neutrons to discern the atomic arrangements in nanoparticles — can be carried out using a transmission electron microscope (TEM) — an instrument found in many chemistry and materials science laboratories.

The researchers describe the TEM-based data-collection technique and computer-modeling analyses used to extract quantitative nanostructural information in a paper just published in the May 2012 issue of the journal Zeitschrift fur Kristallographie.

"The ability to collect PDF data using an electron microscope places this powerful nanocrystallographic analysis method into the hands of scientists who need it most — the people synthesizing novel nanoparticles and nanostructures," said Simon Billinge, a researcher at both Brookhaven and Columbia University's School of Engineering and Applied Science and a long-term user of the NSLS, who led the research.

"State-of-the-art experiments will still be carried out at x-ray synchrotrons and high-tech neutron-scattering facilities," said Billinge, a professor of Materials Science and Applied Physics and Applied Mathematics at Columbia Engineering. "But this new development removes significant barriers to more widespread use of the method, potentially making PDF part of the standard toolkit in materials synthesis labs. It's rather like moving nanocrystallography from being available only with a prescription to being available over the counter," he said.

In both the synchrotron and TEM-based methods, the essential technique is the same: bombard a sample with a beam — x-rays, in the case of a synchrotron, or electrons at a TEM — and measure how the rays/particles interact with and bounce off the atoms in the sample. The result is a diffraction pattern that can be translated into measurements of the distribution of distances between pairs of particles within a given volume — the atomic pair distribution function (PDF). Scientists then use computational programs to convert the PDFs into 3-D models of atomic structure.

Electron diffraction had been used to study the structure of molecules in the gas phase and amorphous thin films, but initially, scientists didn't think that electrons would be appropriate for obtaining reliable PDFs from critical nanocrystalline materials because, unlike x-ray photons, electrons scatter strongly, distorting the diffraction pattern. This new work demonstrates that, under the right circumstances and with the correct data processing, quantitatively reliable PDFs of small nanoparticles — precisely the ones that are difficult to characterize using standard methods — can be obtained with the TEM.

Another advantage is that the technique allows analysis of atomic-level structural arrangements using the same tool already used to obtain low- and high-resolution images and chemical information for nanostructures — that is, the same TEM can be used to provide complementary kinds of information.

"The fact that the real-space images and the diffraction data suitable for structural analysis can be obtained at the same time from the same region of a material results in more complete information for the characterization of the sample," said Milinda Abeykoon, a postdoctoral researcher at Brookhaven and the first author of the paper.

In the current study, scientists working with co-author Mercouri Kanatzidis at Northwestern University and ANL synthesized nanocrystalline thin films and gold and sodium chloride (NaCl) nanoparticles and used a TEM at Northwestern to acquire PDFs of these samples. The Brookhaven/Columbia group studied similar samples using synchrotron x-rays at NSLS, and analyzed all the data before comparing the resulting PDFs and atomic structures.

The PDFs from the x-ray and electron data were highly similar.

"In some cases the strong electron scattering did introduce some distortions in the PDF, as originally feared," Billinge said. "However, surprisingly these problems only affected certain less important structural parameters — and even resulted in an enhancement of the signal in a way that may be used in the future to yield a higher resolution measurement. That was an unexpected gift!"

The research team is continuing to look for ways to remove barriers to data processing to make the method more straightforward — and move it from proof-of-principle concept into widespread standard use.

###

This research was funded by DOE's Office of Science and by the National Science Foundation. The National Synchrotron Light Source at Brookhaven is also supported by the DOE Office of Science.

DOE's Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit http://science.energy.gov/.

Simon Billinge puts the research in context:
"The next generation of high-performance materials that scientists are studying for applications like batteries, fuel cells, drug delivery, and photovoltaics are highly complex. We are trying to engineer them at the nanoscale to give them particular properties to improve their performance. A huge experimental challenge is to characterize experimentally these heterogenous, nanostructured, complex materials — including determining where the atoms are located, their dynamics, and how they interact with outside stimuli such as photons of light. If people want lighter laptops with more computing power and longer battery life to take with them in their emission-free cars that go 400 miles without a fill-up/recharge — and which pull away from the stoplight like a Ferrari — then we scientists are going to have to solve these problems! Our research is a tiny (but important) step in that direction."

Columbia Engineering

Columbia University's Fu Foundation School of Engineering and Applied Science (http://www.engineering.columbia.edu/), founded in 1864, offers programs in nine departments to both undergraduate and graduate students. With facilities specifically designed and equipped to meet the laboratory and research needs of faculty and students, Columbia Engineering is home to NSF-NIH funded centers in genomic science, molecular nanostructures, materials science, and energy, as well as one of the world's leading programs in financial engineering. These interdisciplinary centers are leading the way in their respective fields while individual groups of engineers and scientists collaborate to solve some of modern society's more difficult challenges.

Brookhaven National Laboratory

One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. Brookhaven is operated and managed for DOE's Office of Science by Brookhaven Science Associates, a limited-liability company founded by the Research Foundation of State University of New York on behalf of Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization. Visit Brookhaven Lab's electronic newsroom for links, news archives, graphics, and more at http://www.bnl.gov/newsroom , or follow Brookhaven Lab on Twitter, http://twitter.com/BrookhavenLab .

Brookhaven Lab media contacts: Karen McNulty Walsh, 631 344-8350, kmcnulty@bnl.gov or Peter A. Genzer, 631 344-3174, genzer@bnl.gov; Columbia Engineering media contact: Holly Evarts, 212-854-3206 (o); 347-453-7408 (c), holly@engineering.columbia.edu

Related Links

Scientific paper: "Quantitative nanostructure characterization using atomic pair distribution functions obtained from laboratory electron microscopes": http://www.oldenbourg-link.com/doi/abs/10.1524/zkri.2012.1510

--------------------------------------------------------------------------------

Karen McNulty Walsh | EurekAlert!
Further information:
http://www.bnl.gov

More articles from Studies and Analyses:

nachricht The importance of biodiversity in forests could increase due to climate change
17.11.2017 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig

nachricht Win-win strategies for climate and food security
02.10.2017 | International Institute for Applied Systems Analysis (IIASA)

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Corporate coworking as a driver of innovation

22.11.2017 | Business and Finance

PPPL scientists deliver new high-resolution diagnostic to national laser facility

22.11.2017 | Physics and Astronomy

Quantum optics allows us to abandon expensive lasers in spectroscopy

22.11.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>