ZAPBOF

The properties of nanomaterials are essentially determined by their three dimensional (3D) structure. Electron tomography currently enables one to measure the morphology and composition of nanostructures in 3D, even with atomic resolution. Strikingly however, these measurements are always performed at room temperature and in ultrahigh vacuum, which are conditions that are completely irrelevant for the use of nanoparticles in real applications. Moreover, nanoparticles often have ligands at their surface, which form the interface to the environment. They influence the growth, thermal stability and drive self assembly. Surprisingly, their exact role has not yet been completely understood and so far, their presence has been completely neglected during electron microscopy investigations. The aim of this program is to overcome these crucial limitations and to enable a deep understanding of the effect of a relevant climate on the structure-property connection of a broad range of nanoparticles and their assemblies. Since two dimensional in situ electron microscopy experiments are simply not sufficient to understand the complex 3D changes in anisotropic nanosystems, I will develop innovative 3D characterization tools, compatible with the fast changes of nanomaterials that occur in a thermal and gaseous environment. To visualize surface ligands without damaging their structure, I will combine direct electron detection with exit wave reconstruction techniques. Tracking the 3D structure of nanomaterials in a relevant climate is an extremely ambitious goal. However, the preliminary experiments in this application demonstrate the enormous impact. Our objectives will enable 3D dynamic characterization of reshaping of nanoparticles, important to improve thermal stability during drug delivery, sensing, data storage or hyperthermic cancer treatment. We will provide quantitative 3D measurements of the coordination numbers of the surface atoms of catalytic nanoparticles and follow the motion of individual atoms live during catalysis. By visualising surface ligands and their interface with nanoparticles in 3D, we will understand their fundamental influence on particle shape and during self assembly. This program will be the start of a completely new research line in the field of 3D imaging at the atomic scale. Even more essential is that the outcome of these challenging studies will certainly boost the design and performance of nanoparticles. This is not only of importance at a fundamental level, but is a prerequisite for the incorporation of nanomaterials in our future technology.

Keywords:NANOPARTICLES

Disciplines:Nanophysics and nanosystems