Boosting Cation Exchange in Self-Assembled Supraparticles through Advanced Electron Tomography Techniques

ended

Self-assembly of nanoparticles (NPs) offers a versatile platform for the design of novel materials with enhanced collective properties. A promising route to achieving tailored properties with NPs is to bring them together into superstructures called Supraparticles (SPs). The greatest potential for bringing forth diverse new properties comes from multicomponent SPs, in which multiple types of NPs are used in the SPs. I propose to use spherical confinement to first build SPs which I will then treat with cation exchange (CE), a powerful tool for synthesizing NPs with controlled structures. The goal is to establish a robust route to structuring multicomponent SPs in a controlled manner and enable the engineering of new SPs with optimal properties for applications ranging from catalysis to photovoltaics. A complete structural analysis of cation exchanged (CE-ed) SPs in 3D is essential as it will reveal the CE process in SPs. I will develop innovative quantitative 3D electron microscopy (EM) techniques to investigate the dynamics of the structural evolution of CE-ed SPs on the single NP level, providing insights into how to achieve optimal properties. Optimization of sample support and development of fast multimode electron tomography will make this possible by eliminate beam damage. Liquid tomography will allow me to fully understand the 3D structures of CE-ed SPs under realistic conditions. By combining in-situ heating and fast multimode electron tomography, I will decipher the mechanism of heat-induced intra- and inter- particle CE in SPs. My program will enable me to understand the interplay between NP shape, stacking and heating on the resulting SP structures. This program will be the start of a completely new research line in the fields of both colloidal science and 3D characterization. The outcome will boost the possibilities for the design and application of functional materials as well as push the limits of 3D EM techniques.