Seminar Speaker: Raymond Unocic, Oak Ridge National Laboratory

“In situ STEM approaches for Interpreting Atomic to Nanoscale Transformation Mechanisms and Kinetics in Functional Nanomaterials”

Abstract

Designing new materials for functional applications depends upon our ability to understand and correlate the material’s structure and chemistry to available material properties and performance. This is even more important for nanoscale materials where thicknesses can be on the order of single atoms to few-atomic layers; therefore, any structural or chemical modification at these length scales can have a profound effect on modifying the electronic, magnetic, optical, and catalytic properties. It is essential to understand the mechanisms by which the atomic structure can be manipulated to tune these specific properties. The scanning transmission electron microscope (STEM) is inherently a versatile materials characterization tool that enables us to establish these critical links via high spatial resolution imaging, diffraction and spectroscopic techniques. However, recent advances in the development and application of in situ/operando STEM techniques present us with new research opportunities and in this presentation, I will highlight several examples of how in situ STEM is being used to improve our fundamental understanding of transformations mechanisms and energetic pathways that lead to the formation of new structures at the atomic scale. Then, I will discuss how novel in situ/operando STEM methods are being used to understand interfacial chemical reactions and ionic transport at the nanoscale. Finally, I will close the presentation with my perspective on future research opportunities for microscopy in advancing materials research.

Speaker Biography

Raymond Unocic is a Senior R&D Staff Scientist and Group Leader of the Materials MicroÅnalysis Group in the Center for Nanophase Materials Sciences at Oak Ridge National Laboratory. He earned his Ph.D. in Materials Science and Engineering from The Ohio State University in 2008, then joined Oak Ridge National Laboratory under the Alvin M. Weinberg Early Career Distinguished Fellowship program from 2009-2011 and has been an R&D Staff Scientist even since. As an expert in aberration-corrected, analytical and in situ/operando STEM, his research is focused on the development and application of novel electron microscopy-based characterization methods for materials science research for the purpose of probing atomic-scaled structure, chemistry and defects of materials for structure-property-function correlations. Over the course of his research career, he has published over 170 peer-reviewed journal articles, and four book chapters, and granted five U.S. Patents. Moreover, he has received several notable awards including the MicroAnalysis Society’s Birks Award, two R&D 100 awards, and several ORNL-UT Battelle Research Team Awards.