Fe3O4/CdSe/ZnS magnetic fluorescent bifunctional nanocomposites

Fe3O4/CdSe/ZnS magnetic fluorescent bifunctional nanocomposites were obtained by depositing heterogeneous semiconductor on magnetic nanoparticles. The structure and properties of the Fe3O4/CdSe/ZnS nanocomposites were fully characterized by TEM, XPS, XRD, SQUID and PL. The results indicate that the Fe3O4/CdSe/ZnS nanocomposites are superparamagnetic and are about 8 nm in size. The quantum yield of the nanocomposites increases from 2-3%in Fe3O4/CdSe to 10-15% in Fe3O4/CdSe/ZnS, together with a red shift of both the absorption peak and PL band. The increase of quantum yield is due to the passivation of the surface of magnetic-CdSe nanocomposites with a ZnS layer.