We report a real-time structural study of the synthesis of nanoparticles (NPs) capped with organic ligands. The present work focuses on the case of zinc oxide (ZnO) NPs capped with thiol (dodecanethiol and hexanethiol), which have attracted much attention due to their dual semiconductor and ferromagnetic properties. X-ray absorption Spectroscopy (both XANES and EXAFS regions) and X-ray Diffraction (XRD) measurements were carried out during the growth of the NPs, in order to gain a deeper understanding of the kinetic of the growing process and the thiol addition.
This is clearly important for tailoring the properties of these kind of systems. In a first step, it is found that while the NP's growth occurs and reaches the maximum size in 2 minutes, the local structure around Zn atoms needs around 20 minutes to be stabilized. In a second step, after adding the thiol, an initial fast adsorption of the thiol molecules takes place, followed by an slower process that ends with the stabilization of a core-shell structure.