UPTON, NY--Staff member Dmitri Zakharov, an electron microscopist at the Center for Functional Nanomaterials (CFN)--a U.S. Department of Energy (DOE) Office of Science User Facility at Brookhaven National Laboratory--has been awarded the 2019 Chuck Fiori Award by the Microscopy Society of America (MSA). The Chuck Fiori Award annually recognizes an outstanding technologist in the physical sciences who has made significant contributions to the advancement of microscopy and microanalysis, such as by developing new techniques.
Zakharov is an expert in environmental transmission electron microscopy (ETEM), a powerful technique for studying the dynamic behavior of materials at the atomic scale. With ETEM, scientists can expose materials to realistic operating conditions such as gaseous reaction environments and elevated temperatures, and capture structural and morphological changes.
"I've always been amazed at how nature is so clever by design," said Zakharov, who first became introduced to electron microscopy as a child, when he visited the workplace of his father, an electron microscopist. "Looking at atoms and seeing how they are arranged is really amazing because you can learn how structure dictates material properties. Electron microscopy is all about structure-property relationships. The uniqueness of ETEM is that you can study materials in conditions that they would normally perform in. For example, ETEM can help us understand why the activity of a catalyst degrades over time, and most importantly, propose a path forward to prolong catalytic activity."
Zakharov's dive into ETEM began at Purdue University's Birck Nanotechnology Center, where he helped install the first "beta" ETEM of the FEI Company Titan model in 2006. Optimization of this ETEM enabled discoveries in the growth of carbon tube-shaped nanostructures (nanotubes) and semiconductor wire-shaped nanostructures (nanowires), and led to subsequent modifications in the commercialized version of the instrument.
As noted in his nomination support letters, performing ETEM experiments is quite challenging because multiple parts of the instrument--at a minimum, the microscope, gas delivery system, sample holder, and image acquisition system--must work together seamlessly at the same time.
"Dmitri is a rare scientist," wrote University of Pennsylvania Materials Science and Engineering Professor Eric Stach, who hired Zakharov as a staff scientist at the Birck Nanotechnology Center and later worked with Zakharov at the CFN. "He has both absolute command of his instrumentation on a technical level and the ability to think at both a high general level and with focused precision about how to solve a wide range of materials problems."
In 2012, Zakharov joined the CFN, which has an aberration-corrected version of the same ETEM (aberrations are imperfections that limit resolution). Over the past seven years, he has contributed to the development and advancement of ETEM techniques. For example, he expanded the range of possible experimental conditions and implemented a specialized camera for acquiring images at a very high frame rate. The enrichment of such capabilities has enabled scientists to carry out more sophisticated experiments.
"Dmitri is such a talented microscopist and a great asset for CFN staff and users," said CFN Director Charles Black. "He has greatly contributed to the science of so many users over the years by working with them to get the very best performance from one of our signature instruments--our aberration-corrected ETEM. It is gratifying to see Dmitri recognized by his scientific peers in MSA."
For example, Zakharov has helped materials scientists at Binghamton University study gas-solid reactions, such as the initial stages of oxidation and reduction in metal oxides. He has also collaborated with material engineers at the U.S. Air Force Research Laboratory to understand growth termination mechanisms for carbon nanotubes. Working with chemical engineers at Harvard University, he has characterized the behavior of a new nanostructured gold alloy that is highly active and selective for alcohol oxidation reactions critical to the chemical industry. Together with researchers at IBM, he has investigated the incorporation of metal silicide nanocrystals into silicon nanowires during growth in the microscope.
For his personal research, one area Zakharov focuses on is the fundamentals of carbon nanotube growth and nucleation on catalyst particles. Ultimately, his goal is to grow nanotubes with the desired chirality--a certain geometric arrangement of carbon atoms forming a nanotube--for desired electronic and mechanical properties. For example, chirality determines whether the nanotube is metallic or semiconducting. Zakharov is also studying the evolution of supported nanoparticle ensembles exposed to different reaction conditions and stabilizing catalyst particles using porous aluminum- and silicon-containing substrates called zeolites.
For Zakharov, it is an exciting time to be doing science. Besides using the ETEM at the CFN, Zakharov often conducts research at Brookhaven's National Synchrotron Light Source II (NSLS-II)--another DOE Office of Science User Facility, located adjacent to the CFN. Here, he uses the ambient-pressure photoelectron spectroscopy (AP-XPS) instrument, which is operated in partnership between the CFN and NSLS-II.
"With AP-XPS, you can expose your sample to the same conditions as in ETEM," said Zakharov. "The data sets acquired by the two techniques are complementary: ETEM provides very local atomic-scale information about a sample with high temporal resolution, while AP-XPS uncovers surface chemistry on a larger scale. By correlating two data sets obtained with the above-mentioned techniques, one could learn much more about the sample than possible with a single technique."
Zakharov is also excited by the opportunities that artificial intelligence and machine learning will afford in analyzing acquired data in real time. He has been working with staff at Brookhaven's Computational Science Initiative to explore such opportunities.
"If you want to take studies of materials' behavior in a certain environment to the next level, you have to quantitatively analyze ETEM images as they are being generated so you can adjust experimental conditions on the fly," said Zakharov. "Enabling this real-time feedback will require algorithms to detect and track particles as they evolve. This is the direction we're going."
Zakharov holds a PhD from the Institute of Crystallography of the Russian Academy of Sciences and an MS from the Department of Theoretical and Experimental Physics at Moscow State Engineering Physical Institute, both in solid-state physics. He conducted postdoctoral research at DOE's Lawrence Berkeley National Laboratory and the Max Planck Institute of Microstructure Physics. Before joining the CFN and the Birck Nanotechnology Center, he was a staff scientist at the Laboratory of Electron Microscopy, part of the Institute of Crystallography of the Russian Academy of Sciences. Over his career, Zakharov has published more than 150 journal and conference papers and has presented more than 30 invited talks nationally and abroad.
The Chuck Fiori Award is one of two Outstanding Technologist Awards. The other one, the Hildegard H. Crowley Award, recognizes a technologist from the biological sciences. In addition to its Outstanding Technologist Awards, MSA has Distinguished Scientist Awards, the Burton Medal, the George Palade Award, and the Albert Crewe Award to recognize early-, mid-, and late-career scientists and technologists. This year's awardees were recognized at the 2019 Microscopy & Microanalysis meeting, which was held from August 4 through 8 in Portland, Oregon.
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