Advanced High Resolution and Dynamic in-situ TEM/STEM Observations of Materials Processes
EMSL Project ID
47296
Abstract
The first goal of this research program is to develop a robust method to quantify the atomic scale changes in structure, composition and bonding that occur at interfaces under a variety of environmental conditions. Although (scanning) transmission electron microscopy has long had the ability to deliver atomic resolution Z-contrast images, interpretation of the image contrast and subsequently the properties of the material being studied, has primarily been on an image by image basis -- in some cases extrapolating a single image to represent the properties of all interfaces in a materials system. However, to truly quantify the properties of interfaces, any atomic scale study must give statistical relevance to the analysis. In addition to an increase in spatial resolution, the advent of aberration correctors has provided a stability and robustness of experimental approach that means the statistical variations across many images can be correlated and quantified. This research will use these features of aberration correction to build on the statistical crystallography methods developed for structural biology and applied previously in materials science to study doping changes in bulk materials. Analysis will focus specifically on oxide interfaces and heterogeneous catalysts under environmental conditions ranging from high vacuum through atmospheric pressure gases to liquids with the ultimate goal of understanding how structures evolve under different operating conditions. The second goal of this project is to develop a fundamental understanding of materials dynamics (from microseconds to nanoseconds) in systems where the required combination of spatial and temporal resolution can only be reached by the dynamic transmission electron microscope (DTEM). In this temporal regime, the DTEM is expected to have atomic spatial resolution, providing an in-situ TEM capable of studying nanoscale dynamic phenomena with several orders of magnitude time resolution advantage over any existing in-situ TEM. For the routine interpretation of DTEM images it will be essential to also perform detailed experiments on the environmental TEM. This capability will be used to study the mechanism of sintering and growth for nanoparticles in and around electrodes and the observation of live organic systems in their hydrated states. The aim for both of these projects is to develop new insights into long-standing scientific problems related to the identification and control of the active sites that are responsible for the selectivity of chemical reactions and the nucleation/growth of nanostructures. In addition to providing time resolved imaging, short pulses of electrons may significantly enhance the capabilities of static bioimaging by mitigating damage and sample deformation issues which limit state-of-the-art bioimaging. This program is expected to involve many graduate students and postdocs, rapidly leading to the education of a new generation of scientists capable of employing the latest dynamic characterization methods.
Project Details
Start Date
2012-02-09
End Date
2014-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members