Fabrication, structure, and properties of Fe _3O _4@C encapsulated with YVO _4:Eu ~+ composites

摘要

The use of carbon shells offers many advantages in surface coating or surface modification due to their surface with activated carboxyl and carbonyl groups. In this study, the Fe _3O _4@C@YVO _4: Eu ~+ composites were prepared through a simple sol-gel process. Reactive carbon interlayer was introduced as a key component, which separates lanthanidebased luminescent component from the magnetite, more importantly, it effectively prevent oxidation of the Fe _3O _4 core during the whole preparation process. The morphology, structure, magnetic, and luminescent properties of the composites were characterized by transmission electron microscopy (TEM), high-resolution TEM, X-ray diffraction, X-ray photoelectron spectra, VSM, and photoluminescent spectrophotometer. As a result, the Fe _3O _4@C/YVO _4:Eu ~+ composites with well-crystallized and core-shell structure were prepared and the YVO _4:Eu ~+ luminescent layer decorating the Fe _3O _4@C core-shell microspheres are about 10 nm. In addition, the Fe _3O _4@C@YVO _4:Eu ~+ composites have the excellent magnetic and luminescent properties, which allow them great potential for bioapplications such as magnetic bioseparation, magnetic resonance imaging, and drug/gene delivery.