Heterogeneous nucleation and growth of CdSe on magnetite seed nanocrystals: The influence of ligand and morphology

The heterogeneous nucleation and growth of CdSe domains on the Fe3O4 seed nanocrystals are hard to be controlled because of significant lattice mismatch between Fe3O4 and CdSe nanocrystals. Current study exploits the choice of surface ligand and crystal morphology for Fe3O4 seed to investigate ways to overcome the energy barrier imposed by the lattice mismatch for the promotion and control of subsequent growth of CdSe nanocrystals on seeded crystals. Results indicate that the growth of CdSe domains on seed nanocrystals not only depends on the affinity of ligands toward seed nanocrystals, but also is affected by the seed ligands in a similar way to synthesizing individual second-domain nanocrystals. Furthermore, preferential growth of CdSe domains on the corner of cubic seeds are observed, and cubic Fe3O4 nanocrystals are favored for the heterogeneous nucleation of CdSe as opposed to spherical ones. A three-stage growth model (heterostructures formation, the adsorption of Se and the heterogeneous nucleation and growth) is proposed, where choice of ligands, geometry features, such as surface curvature and defects are found to have significant impact to overcome energy barrier from lattice mismatch.

► The effect of capping ligand and morphology of seed nanocrystals on heterostructure was investigated. ► A three-stage growth model for heterostructure nanocrystals was proposed. ► Ligands, surface curvature and defects are important to overcome energy barrier.