Atomic-Resolution In-Situ Characterization of Low-Dimensional Materials

Abstract of the talk

The last few years have seen a paradigm change in the way we characterize materials, with unprecedented improvements in both spatial and spectroscopic resolution being realized by aberration-corrected transmission electron microscopes. While spatial and energy resolutions better than 60 pm and 10 meV have been reported in a transmission electron microscope, aberration-correction has also enabled a large variety of in-situ experiments at close to atomic resolution. Using this approach, the intercalation of mono as well as multi-valent ions into cathode materials, the dynamics of vacancies, and the interactions between gases and nano-particles can now be directly observed, to only mention a few examples. Moreover, the development of new liquid/gas sample holder technologies now allows for the same sample to be characterized under operando conditions using both electron and x-ray imaging and spectroscopies.  This multi-modal approach will provide new opportunities for characterizing solid/liquid interfaces, electro-chemical reactions and interfacial diffusion at unprecedented resolution.

In this presentation, I will focus on the atomic-scale in-situ characterization of complex oxide thin films, transition metal dichalcogenides, as well as solid-liquid interfaces. In particular, I will demonstrate the effects of oxygen vacancy ordering at low temperatures in (Pr,Y)CaCoO3, a novel approach to measuring temperature in 2D materials and graphene-based liquid holders that enable the direct characterization of solid-liquid interfaces close to atomic-resolution. I will also discuss my vision for the future of both electron and X-ray microscopy, including monochromated electron-sources, new data processing approaches for low dose microscopy as well as multi-modal methods combing x-ray and electron scattering.   

Biography of the Speaker

Robert F. Klie is a Full Professor of Physics at the University of Illinois at Chicago and a world leader in the experimental study of interfaces in complex oxide materials. He focuses on atomic scale Z-contrast imaging, electron energy-loss spectroscopy (EELS) and in-situ characterization of energy materials. Dr. Klie has pioneered in-situ characterization of structural and electronic phase transitions in complex oxide materials using aberration-corrected scanning transmission electron microscopy (STEM). He has published over 130 peer-reviewed papers with more than 3,200 citations, given more than 75 invited talks at prestigious international conferences, and has an h-index of 29. Dr. Klie’s scientific achievements have been recognized by a number of prestigious awards, including the Brookhaven Goldhaber Distinguished Fellowship and the University of Illinois Researcher of the Year award. Over the last 10 years. Dr. Klie has built one of the premier microscopy centers at the University of Illinois at Chicago with more than 157 regional and inter-national users.