Two- and three-dimensional transmission electron microscopy of colloidal nanoparticles: from structure to composition

Date: 5 September 2017

Venue: Campus Groenenborger, U0.24 - Groenenborgerlaan 171 - 2020 Antwerpen (route: UAntwerpen, Campus Groenenborger)

Time: 4:00 PM

PhD candidate: Eva Bladt

Principal investigator: Sara Bals

Short description: PhD defence Eva Bladt - Faculty of Science,Department of Physics



Abstract

To understand the structure-property relationship of nanomaterials and to trigger the synthesis of novel nanomaterials with predefined properties, a three-dimensional (3D) investigation at the nanoscale and below is of key importance. To reach this goal, electron tomography is required. The technique has progressed significantly the last decade, but progress in materials science is leading to even higher demands concerning characterization. The growing interest in hetero-nanostructures requires clear knowledge on both the shape and chemical nature of the structure in 3D. Therefore, a need for spectroscopic electron tomography emerges.

The ever increasing complexity in composition of novel nanostructures is often accompanied by an increasing sensitivity towards the electron beam. Depending on the degree of sensitivity, the conventional acquisition of a single projection image is already troublesome and low dose techniques are required. When expanding the investigation to 3D, the acquisition of a (large) set of images necessary for an electron tomography experiment is far from straightforward.

Finally, although electron tomography yields very precise and local information in 3D of nanoparticles, a major drawback remains that it is not straightforward to perform statistically relevant studies in 3D as the technique is quite time-consuming. Therefore, one of the emerging challenges in the field is to increase the throughput of 3D reconstructions of nanoparticles. In my dissertation, different advanced transmission electron microscopy techniques are developed and optimized to tackle these three challenges.



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