Particle & Particle Systems Characterization, 2018, vol 35, 5, pp. 1700361
Seed-mediated heteroepitaxial growth provides a versatile synthetic approach to a diverse set of geometrically distinct bimetallic heteronanostructures. In bimetallic nanocrystal systems, interfacial heteroepitaxial growth typically occurs between structurally similar metals with lattice mismatch below 5%, whereas controlled epitaxial growth of bimetallic nanocrystals comprising metals with larger lattice mismatches or even dissimilar crystalline structures has long been challenging. Here, the epitaxial growth of both face-centered cubic (fcc) and hexagonal close-packed (hcp) Ni on fcc Au nanocrystal seeds in polyol solvents is systematically investigated, to shed light on the complex mechanisms underpinning the intriguing geometric evolution of lattice-mismatched bimetallic nanocrystals during seed-mediated heteroepitaxial overgrowth. The success in geometry-controlled syntheses of a series of Au–Ni bimetallic heteronanostructures, such as conformal core–shell nanoparticles, asymmetric heterodimers, and multibranched core–satellite nanocrystals, represents a significant step toward the extension of nanoscale interfacial heteroepitaxy from lattice-matched bimetallic systems to the ones exhibiting large lattice mismatches and even dissimilar crystalline structures. The insights gained from this work serve as a central design principle that guides the development of new synthetic approaches to architecturally sophisticated and compositionally diverse multimetallic heteronanostructures.