The effects of capping agents on the synthesis of magnetic-luminescent Fe₃O₄ -InP/ZnSe nanocomposite material

Abstract

Magnetic luminescent nanoparticles of an iron oxide (Fe₃O₄) superparamagnetic core and an indium phosphide/zinc selenide (InP/ZnSe) quantum dot shell are reported. The magnetic nanoparticles (MNP’s) and quantum dots (QD’s) were each synthesized separately before conjugation. The MNP’s were functionalized with a thiol-group allowing the QD shell to bind to the surface of the MNP by the formation of a thiol-metal bond. The nanocomposite was capped with 3-mercaptopropionic acid, 1-propanethiol, 2-methyl-1-propanethiol and their properties investigated using the characterization techniques: high- resolution transmission electron microscopy (HR-TEM), energy-dispersive spectroscopy (EDS), UV-vis, scanning electron microscopy (SEM), superconducting quantum interference device (SQUID), and photoluminescence. These techniques yielded significant information on particle size, morphology, dispersion, and chemical composition including luminescence and florescence.