Evidence for a non-epitaxial growth-detachment mechanism in seed-mediated glycothermal synthesis of colloidal garnet nanoparticles

Seed-mediated synthesis of nanoparticles typically results in hetero-epitaxial growth, which eventually leads to larger nanoparticles with core–shell morphology. Counter intuitively, a seed-mediated glycothermal synthesis of large-lanthanide gallium/aluminum garnets nanoparticles (NPs) (Ln 3 (Ga/Al) 5 O 12 , Ln = Lanthanide, e.g., Tb/Gd/Eu) using undoped YAG (Yttrium Aluminum Garnet, Y 3 Al 5 O 12 ) NPs as seeds, yielded highly dispersed colloidal garnets NPs of interest with no discernible core–shell features. Moreover, most of them are physically separate from the seeds. By combining DFT modeling with kinetic studies on material and optical properties, we offer a thorough and comprehensive insight into the mechanistic aspects of this non epitaxial NP formation. Catalytic growth of an amorphous Ln-(Al/Ga)-based material on top of the seed ligand is predicted computationally and confirmed experimentally, followed by detachment of the garnet NPs of interest away from the ligand-protected seeds once garnet crystallization occurs. This novel mechanism could be leveraged to overcome high formation barriers and enable seed-mediated synthesis of colloidal garnet nanoparticles with large lanthanides, or even beyond, without core–shell structure.