MSE Colloquium
Joerg Jinschek, FEI Company
“Atomic Scale Analysis of Functional Nanomaterials”
Abstract
The focus on more efficient energy conversion, use and storage, as well as on environmental protecting technologies, relies strongly on the advancement of functional nanomaterials. Understanding the state and properties of such nanomaterials demands detailed insights, also on the atomic scale. To our advantage, atomic scale electron microscopy (EM), markedly advanced by utilizing recent hard- and software improvements, has become a powerful and indispensable tool for characterizing those nano structures.
Ongoing activities concentrate on methodological aspects of state-of-the-art EM and thereby open routes towards atom sensitive imaging of nanostructures (based even on light elements) that play a crucial role in numerous applications. The advancement in single atom imaging will be illustrated in case of imaging graphene, where ‘true atomic resolution’ has been achieved.
However, the actual state and function of nanomaterials ‘in operation’ cannot always be inferred from examination under standard EM high vacuum and room temperature conditions or from postmortem EM studies. In situ techniques enable visualization of structural evolution under operational (or environmental) conditions, thereby providing new insights in important materials science questions. EM imaging schemes will be discussed that focus on maintaining spatial resolution of in situ studies, while controlling electron beam / structure interactions. For instance, the inherent atomic scale microscope resolution can indeed be retained in an aberration-corrected environmental microscope (e.g., Titan ETEM G2) under optimized electron illumination conditions. Using a recent application example, it will be highlighted that this enables atomic scale visualization of solid heterogeneous catalysts and their structural evolution in reaction environments and is instrumental to obtain detailed knowledge about catalytic reaction mechanisms.