Synthesis and characterization of core/shell Fe3O4/ZnSe fluorescent magnetic nanoparticles

We report on the successful preparation and characterization of fluorescent magnetic core/shell Fe3O4/ZnSe nanoparticles (NPs) with a spherical shape by organometallic synthesis. The 7 nm core/3 nm shell NPs show good magnetic and photoluminescence (PL) responses. The observed PL emission/excitation spectra are shifted to shorter wavelengths, compared to a reference ZnSe NP sample. A dramatic reduction of PL quantum yield is also observed. The temperature dependence of the magnetization for the core/shell NPs shows the characteristic features of two coexisting and interacting magnetic (Fe3O4) and nonmagnetic (ZnSe) phases. Compared to a reference Fe3O4 NP sample, the room-temperature Neel relaxation time in core/shell NPs is three times longer. (C) 2011 American Institute of Physics. [doi:10.1063/1.3565190]