Selective etching of binary nanoparticle superlattices via thermally induced asymmetric ligand evolution.

We report a method to selectively etch either component in NaYF4/Fe3O4 binary nanoparticle superlattices using a single etchant. Thermally-induced evolution of oleate ligands on the NaYF4 nanoparticles reverses their relative etching susceptibility in oxalic acid, yielding non-close-packed nanoparticle arrays with tunable architectures.