A FEI Talos F200X operated at 200 kV, equipped with a high-angle annular dark-field (HAADF) detector was used for electron microscopy characterization. The asprepared colloidal dispersions were dropped on copper TEM grids (Sigma-Aldrich), placed on an absorbing filter paper. The solvent was left to evaporate. The samples were characterized by imaging at least 3 randomly selected areas at 3 different magnifications. Typically, at least 100 NPs were used to estimate the diameter of the NPs (N values reported below correspond to the number of NPs counted). The ImagJ software was used for size analysis.