A direct synthesis of water soluble monodisperse cobalt and manganese ferrite nanoparticles from iron based pivalate clusters by the hot injection thermolysis method

Abstract

Highly monodisperse water soluble cobalt ferrite (CoFe2O4) and manganese ferrite (MnFe2O4) nanoparticles were synthesised by the hot injection thermolysis of pivalate clusters as single source precursors. The precursors [Fe2CoO(O2CtBu)6(HO2CtBu)3] (1) and [Fe2MnO(O2CtBu)6(HO2CtBu)3] (2) were decomposed in a mixture of polyvinylpyrrolidone (PVP) (capping agent) and triethylene glycol (TREG) (solvent) at 285°C to produce cobalt ferrite and manganese ferrite nanoparticles, respectively. The effect of the PVP on the size and morphology of the nanoparticles synthesised was investigated. Smaller sized nanoparticles of cobalt and manganese ferrite nanoparticles were obtained at higher PVP concentration and larger nanoparticles were produced at lower PVP concentrations. The ferrite nanoparticles produced are monodisperse, directly dispersible in water without any further size selection/postsynthesis procedure. The nanoparticles were characterised by powder X-ray diffraction (p-XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), energy dispersive spectroscopy (EDS) and selected area electron diffraction (SAED).