Selective Etching of Binary Nanoparticle Superlattices via Thermally-induced Asymmetric Ligand Evolution

Abstract

We report a method for the selective etching of NaYF4/Fe3O4 binary nanoparticle superlattices using a single etchant. By leveraging the thermally-induced evolution of oleate ligands on NaYF4 nanoparticles, we can effectively reverse the relative etching susceptibility of the two components in oxalic acid. This mechanism allows for the targeted removal of either component simply by tuning the duration of thermal treatment. The resulting non-closepacked nanoparticle arrays possess tunable architectures that are otherwise difficult to achieve through direct self-assembly.