Delivering New Capabilities for In Situ, Molecular-Scale Imaging
PNNL scientists summarize ambient ionization techniques
PNNL scientists Julia Laskin and Ingela Lanekoff summarized key developments and applications of ambient ionization techniques based on liquid extraction used in mass spectrometry imaging. Their review appeared in the Fundamental and Applied Reviews in Analytical Chemistry 2016 special issue.
Because of their potential to improve the efficiency of electricity generation, understanding the nanostructure and composition of each phase of soft magnetic materials is important. The article, “Mass Balance and Atom Probe Tomography Characterization of Soft Magnetic (Fe65Co35)79.5 B13Si2Nb4Cu1.5 Nanocomposites,” was featured on the cover of the June 2015 issue of IEEE Transactions on Magnetics, and described work to further that understanding.
PNNL found dust particle surface reshaped during atmospheric passage, altering ice-forming ability
Researchers at PNNL found that miniscule particles of airborne dust, thought to be a perfect landing site for water vapor, are altered by the pollution they encounter in the atmosphere during their cross-continental journey. After modifying dust particles in the laboratory to mimic their encounter with pollution from vehicle exhaust and biomass burning, the team discovered some conditions favor cloud-ice-forming potential more than others.
Congratulations to Dr. B. Layla Mehdi at Pacific
Northwest National Laboratory for receiving a 2015 Materials Research Society Postdoctoral Award. She was chosen for
her work on the protective and eventually smothering SEI layer that forms around a lithium-ion battery's electrode. Using electron
microscopy, she watched the layer form as liquid swirled around
and the battery charged and discharged. "It's like putting a camera inside
a battery and watching what happens, as opposed to working on a battery post
mortem," Mehdi said.
Imaging the nanoscale world inside a battery
Rechargeable Li-ion batteries are common in portable electronics and in
today’s plug-in hybrid electric vehicles. Current generation cathode
materials lose their structural integrity after repeated
charge-discharge cycling, resulting in voltage fading and capacity loss.
Understanding the actual mechanisms of degradation is needed to design
longer lasting and higher performance batteries, but degradation has
been extremely difficult to study in detail due to the challenge of
imaging and quantifying the distribution of light elements in Li-ion
battery electrodes. To examine this degradation process in unprecedented
detail, researchers are using a variety of advanced methods to monitor
changes in the distribution of elements in fresh cathodes and cathodes
at different stages of cycling. The new measurements have revealed an
obscure and unexpected capacity-loss mechanism that occurs in some
formulations of a new electrode being designed to enhance performance of
advanced Li-ion batteries.
3D imaging of biofilms shows interactions of cells, structure, and environment
Scientists can now see biofilms, structured communities of microbes, in 3D and real time thanks to a microfluidic reactor developed at Pacific Northwest National Laboratory. The System for Analysis at the Liquid Vacuum Interface (SALVI) recently produced the first 3D images of live biofilms using time-of-flight secondary ion mass spectrometry, providing a fresh view of these complex structures.
Former PNNL postdoc Meng Gu is the recipient of the Microscopy Society of America’s 2015 Albert Crewe Award for his contributions to the field of microscopy and microanalysis, and his outstanding work on the discovery of nickel segregation in battery materials.
A new conference hosted by EMSL and the Chemical Imaging Initiative at PNNL
Registration is now open for the "Electron Microscopy for Biological, Environmental, and Energy Research Symposium" to be held on July 29-30 at EMSL in Richland, Wash. Organized by the Chemical Imaging Initiative and EMSL at the Pacific Northwest National Laboratory, EMBEER focuses on recent developments in instrumentation and methods utilizing microscopy.
Volcanic ash proves inefficient cloud ice maker
A 2010 Icelandic volcano's ash plume caused havoc for vacationers across Europe. But did it also dramatically change clouds? Researchers at PNNL found that volcanic ash is not as efficient as common dust in birthing cloud ice particles. Using a novel laboratory testing chamber they formed cloud ice, a process called ice nucleation, around particles of dust and volcanic ash. Their results revealed the importance of optimal particle structure to efficiently attract super cold water vapor to nucleate ice.
Dr. B. Layla Mehdi, a Pacific Northwest National Laboratory materials postdoctoral researcher, has received a 2015 M&M Post-Doctoral Researcher Award from the Microscopy Society of America. She earned the award for her paper entitled, “Quantification of Electrochemical Nanoscale Processes in Lithium Batteries by Operando ec-(S)TEM.” The award includes complimentary registration to the Microscopy & Microanalysis 2015 Annual Meeting and $1,000 to cover travel expenses. Mehdi will accept her award at the opening plenary session of the 2015 meeting, being held Aug. 2-6 in Portland, Ore.
Years of results regarding secondary organic aerosols reduce uncertainty in climate projections
For the past 20 years, models explained one-tenth of the carbon-rich secondary organic aerosols measured in the air. The problem turned out to be a series of basic assumptions used in the models due to a lack of experimental data. The models assumed the particles were liquids and were rather short-lived on their journey away from their sources. All of these assumptions and more were proven false by Dr. Alla Zelenyuk and her colleagues at Pacific Northwest National Laboratory, Imre Consulting, University of Washington, and University of California at Irvine.
Review identifies gaps to be filled to quantify brown carbon's impact on environment, climate
Researchers from Pacific Northwest National Laboratory and University of California, Irvine published an invited comprehensive manuscript reviewing the chemistry of atmospheric brown carbon -- a type of organic aerosol characterized by an absorption spectrum that smoothly increases from visible to ultraviolet wavelengths. In the review manuscript, the authors summarized field observations, laboratory experiments, and modeling studies describing the role of brown carbon in air pollution and climate forcing -- the difference of sunlight absorbed by earth and energy radiated back to space.
Dr. Nigel Browning at Pacific Northwest National Laboratory was quoted in the Proceedings of the National Academy of Sciences on filming chemical reactions at the atomic scale. The PNAS news article, "Core Concept: Capturing atoms in motion" by Danielle Venton, discusses the development of the dynamic transmission electron microscope that is planned to come online in 2015. The microscope is part of the U.S. Department of Energy Office of Science's Office of Biological and Environmental Research funded EMSL user program. The instrument will provide the ability to film chemical reactions at the atomic scale. Browning is the project leader for the DTEM and directs the Chemical Imaging Initiative at PNNL.
New device lets scientists take images of lithium battery as it works and recharges
To gain an atomic-level understanding of what happens inside the ubiquitous lithium battery, scientists designed and implemented an operando electrochemical stage. Using this stage inside a state-of-the-art aberration-corrected transmission electron microscope, they took nanoscale-resolution pictures of lithium ions as they are deposited on or dissolve off of an electrode while the battery runs. With the new stage, scientists can directly image changes as they occur. This information is vital to control performance- and safety-limiting processes.
In the last 5 years, scientists have come a long way in characterizing reactions in aqueous environments
Scientists' review of sailing into the uncharted waters of real time, in situ monitoring of catalytic conversions in water and other liquids was chosen as a hot article by Catalysis Science and Technology. The article is available for free during March 2015.
Collaborative environment for experimental facilities, computational modeling, and federated data science capabilities drives innovation
The combination of leading-edge microscopy facilities, computational modeling, and federated data science capabilities—as well as cross-domain collaborations—can significantly advance fundamental scientific understanding and control of the synthesis and functionality of energy storage and conversion materials. A series of demonstrations, initially presented by scientists, including PNNL’s Kerstin Kleese van Dam, at SC14 in New Orleans, showcased the ongoing work of DOE’s Data Science Centers and how these collaborative, multi-institutional environments are improving methods for collecting, analyzing, and sharing Big Data and, most notably, driving innovation in materials science.
Research led by Dr. Xiao-Ying Yu, a scientist at Pacific Northwest National Laboratory and her team developed PNNL's System for Analysis at the Liquid Vacuum Interface, or SALVI, allowing—for the first time—imaging of liquid samples reacting in real-time and a realistic environment. They won a prestigious Excellence in Technology Transfer Award in 2015 from the Federal Laboratory Consortium for Technology Transfer (FLC).
Scientists examine the information content in nanoscale chemical images
Light waves trapped on a metal's surface can interrogate the nearby molecules about their chemical identity through the molecule's characteristic vibrations, which act as fingerprints. Scientists at Pacific Northwest National Laboratory (PNNL) "saw" the interaction between the molecules and the trapped light waves or surface plasmons. Their fundamental endeavor could lead to breakthroughs in interpreting ultrasensitive chemical images for characterizing new materials with potential uses in catalysis and energy conversion.
Carbon-rich chemicals coat sea salt particles, altering their structure and possibly changing the atmosphere
When ocean waves make bursting whitecaps or crash against the shores, tiny particles of sea spray enter the atmosphere. Once airborne, the particles are quickly coated by organic chemicals. The chemicals, emitted by diverse sources, cause the particles to evolve, according to scientists at Lawrence Berkeley and PNNL. Using complementary chemical imaging techniques, they found that when temperature and humidity rise, reactions within particles create organic salts. These reacted particles, when chilled, become glass-like lumps.
Dr. Galya Orr has been asked to be a member of the editorial advisory board of Chemical Research in Toxicology, a peer-reviewed scientific journal published by the American Chemical Society. Orr is a senior research scientist and the Cell Isolation and System Analysis capability lead at EMSL. She is also a key collaborator on a Chemical Imaging Initiative project investigating the structure and dynamics of biological systems. The initiative is part of Pacific Northwest National Laboratory.
Popular aluminum oxide created by interlacing different crystal forms
The exhaust system in your car and the plastic cup holding your drink, along with countless other products, rely upon reactions driven by catalysts supported on aluminum oxides. Characterizing these aluminum oxides or alumina has been challenging. For the first time, scientists at Pacific Northwest National Laboratory and FEI Company obtained an atomically resolved view of delta alumina. The team showed that the oxide is two crystal forms or variants woven together.
Arun Devaraj and Daniel Perea, Pacific Northwest National Laboratory, were interviewed about their chemical imaging research for Mitch Jacoby's cover story in Chemical & Engineering News.
Non-uniform evaporation prevents scientists from seeing every atom on a surface
On the surface of a battery's electrode, a material that stores wind energy, or on nearly any other surface, scientists can use atom probe tomography to identify and locate almost every atom. But some atoms evaporate non-uniformly before they are identified-reminiscent of the angels' share, the amount of wine or whiskey volume lost to evaporation during barrel aging. Scientists at Pacific Northwest National Laboratory and the University of Rouen revealed which atoms evaporate in mixed materials, where there are many different types of atoms. They managed this feat by correlating data from three techniques, accounting for all of the atoms and determining how atoms were evaporating from APT.
Designing controlled, reproducible experiments in an in situ liquid stage
Using in situ liquid transmission electron microscopy to probe nanomaterials is a difficult task for scientists, as electron beams perturb the sample and induce artifacts. At Pacific Northwest National Laboratory and University of California, Davis, scientists demonstrated that the choice of electron beam energy has a strong effect that goes far beyond merely increasing the concentration of reducing radicals. They also found that when compared to solid samples, radicals formed in the liquid phase are more mobile, and ultimately dictate the choice of electron microscopy imaging mode.
Congratulations to materials postdoctoral researcher Layla Mehdi, who received a Robert P. Apkarian Memorial Scholarship to attend the Microscopy & Microanalysis (M&M) 2014 Annual Meeting August 3-7 in Hartford, Connecticut. She presented a poster titled "Direct Observation of Li2O2 Nucleation and Growth with In-Situ Liquid ec-(S)TEM," research developed under the Joint Center for Energy Storage Research project.
Researchers collaborate to see particles in real time in their native environment
Like sharks hunting their prey, soft nanoparticles should quickly navigate through the body's waters and attack cancerous cells, destroying the diseased tissue and leaving the rest alone. That's the goal. The challenge is understanding how the particle behaves in liquids, something most microscopes don't handle. Thanks to fortuitous discussions as part of the initial formation of the PREMIER Network, scientists studying the particles at the University of California at San Diego and the University of Pittsburgh teamed up with microscopists at Pacific Northwest National Laboratory (PNNL) and, together, they obtained clear images of the particles moving liquids.
New approach pinpoints locations in simple zeolite catalysts
Employing a combination of methods devised at Pacific Northwest National Laboratory and the Swiss Light Source, scientists determined the distribution of aluminum ions in zeolites, which are widely used by industry. In the first example of this approach, the scientists analyzed two chemical compositions of a structural variant. They found that the aluminum atoms, which are critical to the catalytic activity, preferentially replace silicon atoms at certain sites.
The 25th Annual Symposium of the Pacific Northwest AVS Science and
Technology Society will be held in conjunction with the Pooled Resources for Electron Microscopy Informatics Education and Research, or PREMIER, Network meeting on September 16-19. The meeting will be held at EMSL in Richland, Washington.
Mass spectrometry technique could lead to answers about how cells interact
To understand how cells converse, scientists at
Pacific Northwest National Laboratory and Oregon Health & Science
University designed an approach that accurately determines the spatial location
of molecules and quantifies lipids and metabolites in biological samples. The
new approach efficiently accounts for signal suppression or matrix effect (see
sidebar) that may significantly alter molecules’ distributions obtained in mass
spectrometry imaging experiments. Compensation for matrix effects is achieved by
adding appropriate internal standards to the solvent used in nano-DESI imaging.
Congratulations to Dr. Julia Laskin on receiving a 2014 Laboratory Director’s Science and Engineering Achievement Award. The award recognizes Laskin for her fundamental contributions to mass spectrometry, in particular for her research involving ion collisions with surfaces.
A small window to the world of liquid interfaces has won an R&D 100 Award for a team of PNNL researchers. Xiao-Ying Yu, Zihua Zhu, Bingwen Liu, Martin Iedema and Matthew Marshall of PNNL and collaborators James Cowin and Li Yan developed the System for Analysis at the Liquid Vacuum Interface (SALVI), a novel innovation that allows a new level of molecular insight and liquid analysis that can be deployed in a range of instruments.
SALVI enables real-time imaging of liquid samples by more than one analytical instrument
Many studies rely on knowing precisely how solids and liquids interact on a molecular level, but liquids evaporate in the vacuum of certain powerful scientific instruments. PNNL developed SALVI, or the System for Analysis at the Liquid Vacuum Interface, that for the first time allows these instruments to image liquid samples in real time. R&D Magazine honored SALVI’s research team with a 2014 R&D 100 award. The magazine selects the 100 most innovative scientific and technological breakthroughs of the year.
Chemical imaging technique provides insights for materials used in fuel production
Direct observation of atomic-level process of a platinum-cobalt nanoparticle catalyst reveals that the cobalt is far from stationary. A collaborative study including scientists at Pacific Northwest National Laboratory shows the cobalt migrates from deep inside the nanoparticle to the surface when surrounded by oxygen. When placed in hydrogen gas, the cobalt migrates back inside the nanoparticle, leaving a thin layer of platinum on the particle's surface.
In situ scanning transmission electron microscopy helps characterize stability, degradation
A team led by Pacific Northwest National Laboratory scientists has uncovered information about high-demand batteries that could improve their performance and longevity. The scientists characterized the stability and interconnected degradation mechanisms in electrolytes commonly used for lithium-ion, or Li-ion, batteries. They obtained detailed chemical imaging data using an environmental liquid stage in a scanning transmission electron microscope (STEM). The detailed characterization offered by liquid-stage STEM can provide unique insights into electrolyte behavior, either for use in future in situ battery studies or to test new electrolytes, winnowing the library of candidate solutions for further characterization and reducing the experimental time spent on less effective electrolytes.
Scientists show that too many electrons at the lithiation front in silicon are a problem
As every cell phone owner knows, lithium-ion batteries fade, holding less energy after each charge. This fading relates to electron-rich regions forming in the electrodes, according to scientists at Pacific Northwest National Laboratory and three universities.
Congratulations to Dr. Ilke Arslan, Pacific Northwest National Laboratory, on joining the editorial board for Microscopy & Microanalysis. The journal provides original research articles on imaging and compositional analysis to biologists, materials scientists, and others interested in microscopy. The publication is the official journal of the Microscopy Society of America and eight other societies.
Provides new look at naturally wet microbial community behavior
A multidisciplinary team at Pacific Northwest National Laboratory is the first to demonstrate imaging of a biofilm's chemical components as they form in hydrated biological samples, rather than from frozen or dried samples. They used a surface technique called time-of-flight secondary ion mass spectrometry to study complex microbiological processes, such as chemical attachment of microbes to surfaces to form biofilms. The work used PNNL's vacuum-compatible liquid probe.
Newest method for determining a protein's shape based on XFEL technology significantly broadens number and type of proteins that researchers can study
Using a unique form of X-ray diffraction called diffract-before-destroy imaging, an international team of scientists led by Pacific Northwest National Laboratory and Lawrence Livermore National Laboratory proved it is possible to study individual monolayers of protein. Previously, X-ray techniques were unable to collect diffraction in the forward or transmitted direction unless proteins stacked into large crystals. The Department of Energy's X-ray Free-Electron Laser (a.k.a. the Linac Coherent Light Source) produces exceptionally bright and fast X-rays that can take a picture rivaling conventional methods with a sheet of proteins just one protein molecule thick. The technique opens the door to learning details of the proteins, aiding understanding of how they cause disease or toxicity.
New approach shows particles and ensembles follow different growth patterns, explaining a frustrating discrepancy in experimental results
Individual silver nanoparticles in solutions typically grow through single atom attachment, but importantly, when they reach a certain size they can link with other particles, according to scientists at Pacific Northwest National Laboratory, the University of California, Davis, and Florida State University. This seemingly simple result has shifted a long-held scientific paradigm that did not consider kinetic models when explaining how nanoparticle ensembles formed. Greater understanding of mesoscale interactions in nanoparticles provides more precision in material synthesis, bringing us closer to tailored materials for catalysis, energy storage, and other uses.
In the search for long-lasting, inexpensive rechargeable batteries, researchers develop more realistic methods to study the materials in action
Researchers at a host of universities and national laboratories including Pacific Northwest National Laboratory have developed a way to microscopically view battery electrodes while they are bathed in wet electrolytes, mimicking realistic conditions inside actual batteries. While life sciences researchers regularly use transmission electron microscopy to study wet environments, this time scientists have applied it successfully to rechargeable battery research.
New probe also couples electrochemistry and imaging approaches to observe interface kinetics
A new microfluidic probe developed by PNNL scientists provides dynamic chemical imaging of the electrode-electrolyte interface in situ. Using this probe, the scientists showed the molecular composition of the reaction products and intermediate species at different stages of the redox cycle in situ using—for the first time—a surface imaging technique that operates in a vacuum.
In the January 2014 issue of Genetic Engineering & Biotechnology News, PNNL's Kerstin Kleese van Dam, an associate division director in CSMD and Technical Lead of the Scientific Data Management Group, is featured as part of an article highlighting the upcoming Big Data and Analytics in Life Sciences Forum, hosted by the International Quality & Productivity Center in Boston on January 27-28, 2014.
Kerstin Kleese van Dam discusses big data.
In the article, "Big Data Expected to Impact Pharma R&D," which also examined how to manage, and benefit from, the vast amounts of data affecting pharmaceutical development, Kleese van Dam is quoted describing the work of the Chemical Imaging, Future Power Grid and Analysis in Motion initiatives at PNNL in creating tools that address this confluence of volume, rate and heterogeneity of informatics data. Notably, she explained the role of three data paradigms that PNNL uses to simultaneously organize and interpret data throughout the research process: always on analysis, analysis in motion and analytics at the edge.
Kleese van Dam will present "Case Study: Advances in Predictive Analytics" at the Big Data and Analytics in Life Sciences Forum on Tuesday, January 28 at 1:30 PM.
Pacific Northwest National Laboratory material scientist Dr. Arun Devaraj was interviewed in December by EMSL director Dr. Allison Campbell about his work using atom probe tomography for PNNL’s Chemical Imaging Initiative. The video is available at http://www.youtube.com/watch?v=hIGEnziLZrY&feature=c4-overview-vl&list=PL6ecvCJPoOtkyNUS2Fssd4FB1oGTehffV.
The November 18 issue of DOE Pulse featured Dr. Ilke Arslan of Pacific Northwest National Laboratory. The article discusses how this diplomat's daughter, who completed her doctoral degree at the age of 25, applies the fundamentals of physics to change the scientific community's view of nanoparticles. Her research is working towards the goal of providing a clear view of a working catalyst in real time, in three dimensions, and at the atomic scale. Arlsan's imaging work is providing fundamental answers for her teammates in PNNL's Chemical Imaging Initiative and Institute for Integrated Catalysis.
Read the DOE Pulse article "Ilke Arslan: A catalyst for clarity."
Nickel segregation, cation spatial distribution, and tightly integrated phases occur in pristine battery material
To prevent fading in a layered lithium cathode that has promise for heavy duty transportation use, scientists at Pacific Northwest National Laboratory, FEI Company, and Argonne National Laboratory obtained a definitive view of a pristine cathode. Controversy has encircled this material, a.k.a., LMNO cathode. Some state it's a solid solution; others, a composite. To address this debate, the team used a suite of instruments and determined the material is a composite with tightly integrated phases where the surface contains higher concentrations of nickel, low concentration of oxygen, and electron-rich manganese. Obtaining this type of clarityaround the fundamentals of the cathodeis necessary if scientists are toimprove the cycle life and capacity of the resulting battery.
Congratulations to Dr. Ilke Arslan at Pacific Northwest National Laboratory on being chosen to attend the 25th U.S. Kavli Frontiers of Science Symposium. This invite-only National Academy event is designed to foster discussions among high-profile young scientists across a wide range of disciplines. Between 80 and 100 scientists under the age of 45 are asked to attend. They are chosen from those who have prestigious awards and honors or are nominated by Academy members or other participants.
Arslan is well known for bringing her physics expertise to chemical imaging and catalysis. She won research fellowships from the Royal Society USA and the National Science Foundation. She received a U.S. Presidential Early Career Award for Scientists and Engineers. She is also a Microscopy Society of America tour speaker.
Congratulations to Dr.
Patricia Abellan at Pacific Northwest National Laboratory on
receiving the Microscopy Society of Spain's Best Ph.D. Thesis in Materials Science award. Her research shows how strain state and interface
structure in oxide nanostructured materials grown by a solution route changed
the material's superconductivity, magnetism and other properties. She also discovered
a novel mechanism for lattice parameter relaxation. She is currently conducting work for the Chemical Imaging Initiative and DOE's EMSL.
Elements clearly identified on 3D map
A new technique developed by
scientists at PNNL and FEI Company lets scientists efficiently resolve
elements’ locations in three dimensions. The technique combines scanning
transmission electron microscopy and X-ray energy dispersive spectrometry with
a new detector arrangement and a brighter electron beam. The result: the fastest,
cleanest view yet of the elements’ placement on a sample smaller than a single
blood cell. The team applied this technique to a lithium-rich nickel-based
material that could be part of tomorrow’s batteries and discovered how nickel
was segregating away from other elements on the material’s surface. Their
results, published in Ultramicroscopy,
is the journal’s most downloaded article in the last 90 days
Invited review shows power of scanning tunneling microscopy to understand and control the surface photochemistry of oxide materials
In their invited review, Dr. Michael Henderson and Dr. Igor
Lyubinetsky at Pacific Northwest National Laboratory show that scanning probe
microscopy techniques, in particular scanning tunneling microscopy, allow
scientists to understand fundamental interactions that are key to our energy
Congratulations to Dr. James De Yoreo, Pacific Northwest National Laboratory,
on earning the 2013 American Association for Crystal Growth Award for his foundational
insights into the processes underlying biomineralization and
Congratulations to Dr. Ilke Arslan, Pacific Northwest National Laboratory, on having her scientific image chosen as the cover art for the North American Catalysis Society meeting. The image depicts the morphological changes of a layered zeolite before and after delamination. Delamination of stacked zeolite sheets provides more accessible surface area where bulky molecules can react -- important for the petrochemical industry.
Basic scientific insights of interest for energy storage, environmental cleanup
A unique chemical imaging tool readily and reliably presents
volatile liquids to scientific instruments, according to a team including Pacific
Northwest National Laboratory. These instruments require samples be held in a
vacuum, which is often incompatible with hydrocarbons and other liquids. Designed
and built at PNNL, this one-of-a-kind sample holder continuously pumps the
liquid through a gold-coated microfluidic chamber. The extremely narrow channel
provides high linear velocity at the detection window and helps overcome the
liquids' tendency to vaporize. Instruments access the liquid via an open
viewing port. Tests with electron microscopes and mass spectrometers prove the
device can operate continuously for up to 8 hours. Further, the device handles
Nigel Browning serves as the Chief Science Officer on PNNL's Chemical Imaging Initiative
A commentary by Dr. Nigel Browning, the Chief Science Officer for the Chemical Imaging Initiative at Pacific Northwest National Laboratory, was recently published in Nature Chemistry. The commentary featured recent four-dimensional electron microscopy (4D-EM) work done by the research group of Nobel prize winning scientist Ahmed Zewail. Browning highlighted the wealth of new information 4D-EM has revealed about how electronic phase transitions occur in individual nanoparticles, how the particle-to-particle variability changes the speed and magnitude of the transition, and how interactions between nanoparticles control the ensemble-average response of the system. The power of 4D-EM to image structural dynamics on the scale of a few hundred nanoseconds and allow the switching dynamics to be quantified makes a unique contribution to the study of nanostructures. A broad class of electronic phase transitions in individual nanomaterials can now be studied directly using 4D-EM.
Researchers have long wanted to "see" chemical, materials, and biochemical processes, in time and space, with enough detail to determine what is occurring at the molecular level. But, they lack the tools to reach this level of clarity. Instead, they must infer what is happening from secondary sources and mathematical models.
The Pacific Northwest National Laboratory is developing the tools and techniques to generate images of chemicals, materials, and biological molecules at the nanometer scale through its Chemical Imaging Initiative. (A nanometer is the length of two hydrogen atoms side by side.)
Achieving molecular-scale clarity requires molecules to be examined in situ—exactly as they are rather than in an intermediate state. Data from two or more experimental tools are needed to adequately describe the molecules, so computational tools are being developed to integrate the data streams.
This level of information will allow scientists and engineers to move from observing chemical, materials, and biological processes to controlling them.
Technical challenges include the following
Develop light-source-based x-ray and vacuum ultraviolet probes coupled with laboratory-based imaging capabilities for three-dimensional tomographic, structural, and element-specific molecular-level probes that would significantly enhance imaging capabilities. Use of these new techniques, for example, could potentially provide an atomic-resolution, in situ "movie" of a functioning photocatalyst or clear characterizations of nanoporous materials and their active sites for batteries and biomolecules.
Develop coupled optical, electron, ion, and scanned probe microscopies to understand chemical and biological transformations and mechanisms. Use of these new techniques could produce useful insights into the mineral-fluid interface in supercritical CO2 or the lifecycle of molecular machinery in microorganisms and microbial communities, among others.