Sizing highly-ordered buckyball-shaped aggregates of colloidal nanoparticles by light extinction spectroscopy

We produced self-assembled, densely-packed and highly-ordered aggregates of silica nanoparticles arranged in a rather regular hexagonal–pentagonal surface lattice. To investigate the formation of these aggregates, produced by means of a spray drying method, we developed a light extinction setup and all related models. It is shown that with a geodesic dome model, to describe their morphology, and a T-matrix method to calculate their extinction cross sections, the size distribution and concentration of these flowing aggregates may be recovered from the inversion of transmission spectra. -- Highlights: ► We produced sphere aggregates with a regular hexagonal-pentagonal surface lattice. ► Their morphology is modeled with geodesic dome and hexagonal close packing models. ► Mie and T-matrix calculations are used to estimate their UV-NIR extinction. ► A fitting-model is used to invert successfully experimental transmission spectra. ► Aggregates size distribution and concentration are determined in-situ and accurately