ChEMS Seminar: In-Situ (S)TEM/DTEM: From High Spatial Resolution to High Temporal Resolution
Abstract: The last few years have seen a paradigm change in (scanning) transmission electron microscopy ((S)TEM) with unprecedented improvements in spatial, spectroscopic and temporal resolution being realized by aberration correctors, monochromators and pulsed photoemission sources. Spatial resolution now extends to the sub-angstrom level, spectroscopic resolution into the sub-100meV regime and temporal resolution for single shot imaging is now on the nanosecond timescale (stroboscopic imaging extends this even further to femtoseconds). The challenge now in performing experiments in an (S)TEM is to implement the in-situ capabilities that will allow both engineering and biological systems to be studied under realistic environmental conditions. Performing experiments using in-situ stages or full environmental microscopes presents numerous challenges to the traditional means of analyzing samples in an electron microscope – we are now dealing with the variability of dynamic process rather than a more straightforward static structure. In this presentation, I will discuss the recent developments in the design and implementation of in-situ stages being pursued at the Pacific Northwest National laboratory (PNNL). Examples of the use of these capabilities for the direct imaging of interfaces and defects, to identify the fundamental processes involved in nucleation and growth of nanostructures from solution, and to investigate the electrochemical processes taking place in next generation battery systems will be presented. As the in-situ stages have been designed to be incorporated into both high spatial resolution aberration corrected (S)TEM as well as into high temporal resolution Dynamic TEM (DTEM), the potential for future experiments to study fast dynamics, including those in live biological structures, will also be discussed.
This work was supported in part by the Joint Center for Energy Storage Research (JCESR), an Energy Innovation Hub funded by the Department of Energy, Office of Science, Basic Energy Sciences. The development of the operando stages was supported by the Chemical Imaging Initiative, a Laboratory Directed Research and Development Program at Pacific Northwest National Laboratory (PNNL). PNNL is a multi-program national laboratory operated by Battelle for the U.S. Department of Energy (DOE) under Contract DE-AC05-76RL01830. A portion of the research was performed using the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the Department of Energy’s Office of Biological and Environmental Research and located at PNNL.
Biography: Nigel Browning’s research focuses on the development of new methods in electron microscopy for high spatial, temporal and spectroscopic resolution analysis of engineering and biological structures. After completing his Ph. D. in 1992, Nigel Browning joined the Solid State Division at Oak Ridge National Laboratory (ORNL) as a postdoctoral research associate before taking a faculty position in the Department of Physics at the University of Illinois at Chicago (UIC) in 1995. He moved to the Department of Chemical Engineering and Materials Science at the University of California-Davis (UCD) in 2002 and also held a joint appointment in the National Center for Electron Microscopy (NCEM) at Lawrence Berkeley National Laboratory (LBNL). In 2005, he moved the joint appointment from LBNL to Lawrence Livermore National Laboratory (LLNL) to become project leader for the Dynamic Transmission Electron Microscope (DTEM). From 2009- 2014, Nigel focused on the development of the DTEM to study live biological structures in the Department of Molecular and Cellular Biology at UCD. In November 2011, he moved to the Pacific Northwest National Laboratory as a Laboratory Fellow and Chief Scientist (now Lead) for the Chemical Imaging Initiative. As of February, 2015, Nigel is also an Affiliate Professor and Distinguished Faculty Fellow in the Materials Sciences & Engineering Department at the University of Washington, Seattle.