Spontaneous Formation of Heterodimer Au-Fe₇S₈ Nanoplatelets by a Seeded Growth Approach

Hybrid nanomaterials offer increased flexibility to achieve heterostructures with controlled functionalities and predictable linkages owing to their synergistic interactions. Here, we have developed a synthetic strategy that produced hexagonal-shaped nanoplatelets (NPLs) of gold-pyrrhotite (Au-Fe₇S₈) with Au embedded inside them by means of a seeded growth method. Using thiol-capped Au nanoparticles (NPs) as a seed, heterogeneous nucleation of the iron precursor was facilitated, leading to the formation of Au-Fe₇S₈ NPLs. The injection temperature and surface ligand of the seed (Au) were two critical factors that determined the homogeneity and final morphology of the Au-Fe₇S₈ NPLs. This strategy was further expanded using Ag NPs as the seed to construct heterodimers, producing Ag₂S-Fe₇S₈ heterostructures.