Bifunctional Superparticles Achieved by Assembling Fluorescent CuInS2@ZnS Quantum Dots and Amphibious Fe3O4 Nanocrystals

Monodispersed superparticles (SPs) consisting of hydrophobic CuInS2@ZnS quantum dots (QDs) were prepared through a self-assembling process induced by introducing ethanol into the cyclohexane solution of the QDs stabilized by 1-dodecanethiol. The solvent polarity-dependent size and size distribution of the resultant SPs were carefully characterized by using scanning electron microscopy, transmission electron microscopy, and dynamic light scattering. The formation and the growth mechanism of the SPs were investigated. By manipulating the nucleation and the growth kinetics through the addition rate of ethanol, the size was effectively tuned without broadening the size distribution of the SPs. By overcoating the SPs with amphibious Fe3O4 nanocrystals (NCs) stabilized by poly(4-vinylpyrollidone), aqueous dispersible SPs were obtained. Inheriting the fluorescent and magnetic properties from the corresponding mother particles, the resultant SPs presented excellent fluorescent and magnetic properties and, thus, may potentially be useful for bioseparation, detection, etc.