HRTEM techniques applied to nanocrystal modeling: towards an 'atom-by-atom'description

摘要

The development of technologies based on nanostructures presents a wide range of challenges for materials scientists and engineers, including the attainment of well-controlled synthesis procedures, the improvement of characterization techniques down to the atomic scale resolution, and the conception and validation of reliable models that can describe materials properties as functions of their morphology and fabrication process. A relevant topic in this scenario is the correlation among the spatial distribution of chemical elements, the surface energy configuration, the growth mechanism, and the resultant nanocrystal 3D morphology. This work presents an overview on the use of advanced HRTEM techniques for the quantitative analysis of nanocrystals and how these results can be used to implement nanocrystals models, which can analytically describe the material features on an atomic level. The presented findings show the combined use of experimental data and theoretical tools, such as image simulation and ab initio surface energy calculations, for the advanced quantitative characterization of nanocrystalline systems. The combination of experimental and theoretical efforts on HRTEM characterization represents a powerful tool for the nanocrystal 3D morphology elucidation with atomic resolution and the chemical/structural properties assessment in a quantitative way. Thereby, it is presented as the stepping stone towards the development of novel approaches to describe nanostructured systems.