Event
MSE Seminar: Dr. Alexandre Foucher, MIT
Wednesday, February 28, 2024
3:30 p.m.
Room 2110 Chemical and Nuclear Engineering Building
Sherri Tatum
301-405-5240
statum12@umd.edu
Advanced in situ (S)TEM characterization techniques to guide the rational design of nanomaterials
Abstract: The rational design of functional nanomaterials depends on our understanding and control of their atomic structure. However, dynamic restructuring effects of these nanomaterials in realistic conditions are not always well understood. For instance, changes in composition, valence state, or morphology can greatly impact the electronic configuration of atoms, ultimately modifying the properties of the sample. Thus, it is necessary to develop advanced in situ characterization techniques to understand nanosystems and guide their design by correlating their atomic structure with their properties. First, I will show how gas-heating in situ STEM imaging and electron energy loss spectroscopy (EELS) can help the understanding of innovative bimetallic nanocatalysts (Au-Pd, Co-Pt, Cu-Pt nanoparticles) in realistic conditions. I will underscore how in situ STEM and EELS can show compositional changes, diffusion, kinetics, oxidation mechanisms and phase transformations that can impact the properties of nanocatalysts. I will also describe how in situ biasing STEM is a powerful approach to understand structural changes in 2D materials and thin films used in electronic devices. I will then highlight how STEM-EELS can be combined with other characterization methods, such as electron pair-distribution function (ePDF) analysis or X-ray absorption spectroscopy (XAS), to get a comprehensive understanding of nanomaterials. Finally, I will close the presentation by describing future research opportunities using advanced transmission
electron microscopy techniques to elucidate the functionality of complex nanomaterials.
Bio: Dr. Alexandre Foucher received a B.S. in Mechanical Engineering at Arts et Métiers
ParisTech and a Master of Materials Science and Nanoengineering at Rice University. He obtained a Ph.D. in Materials Science at the University of Pennsylvania in 2022 and worked with Pr. Eric A. Stach. His thesis focused on in situ gas-heating STEM analysis of bimetallic nanocatalysts. He is currently a postdoctoral associate at MIT in the group of Pr. Frances M. Ross and focuses on in situ STEM investigation of 2D films for novel transistors and memory devices.
