MSE Colloquium: Dr. Renske van der Veen, Ultrafast Electron Microscopy: a New Tool to Study Chemical Dynamics at the Nanoscale

Ass't Prof., Dept of Chemistry and Materials Research Lab, Un of Illinois, Urbana-Champaign

Abstract

In situ transmission electron microscopy has become a powerful technique to study functional nanomaterial dynamics in response to electrical, chemical, electrochemical, thermal, and/or electromagnetic fields prevalent under operating conditions. The time resolution, however, is typically limited by the maximum frame rate of the detector, which is at best in the kHz regime. Ultrafast transmission electron microscopy combines the high time resolution of laser spectroscopy with the excellent spatial resolution of electron microscopy techniques. The structural and electronic changes in the material are initiated by short (fs, ps, ns) laser pulses, which are followed by similarly short photoelectron pulses for probing the dynamics by means of imaging, diffraction, or energy-loss spectroscopy (EELS) within the electron microscope. In this talk I will present our dynamic environment transmission electron microscope (DETEM) at the University of Illinois. This versatile instrument enables time-resolved in-situ studies of fast (fs-ms) material processes in gaseous and liquid environments that are triggered by light, heat, chemical flux, electrical bias or strain. I will give examples of studies using light excitation as the trigger, including nanosecond-resolved single-nanoparticle electron diffraction and real-space imaging of spin crossover phase transitions and ultrafast (fs,ns) EELS of light-induced dynamics in graphite thin films. 

Bio

 

Renske van der Veen obtained her B.S. and M.S. degrees in Chemistry from the Swiss Federal Institute of Technology (ETH) in Zürich in 2006. In 2010 she received her Ph.D. in the field of ultrafast X-ray science from the École Polytechnique Fédérale de Lausanne (EPFL) and the Swiss Light Source. After working as a postdoctoral fellow at the California Institute of Technology, she became a project group leader at the Max Planck Institute for Biophysical Chemistry in Göttingen. She joined the University of Illinois faculty as an Assistant Professor in Chemistry in August 2015, and is affiliated with the Materials Research Laboratory and the Materials Science and Engineering Department. She is interested in the study of atomic-scale mechanisms of light-induced processes, such as photoswitching, photovoltaics and photocatalysis.

https://www.vanderveen-lab.com/