Production and Characterization of Magnetic‐Luminescent Fe3O4@ZnO:RE Composite Nanoparticles for Biomedical Application

Magnetic‐luminescent composite nanoparticles (Fe 3 O 4 @ZnO:RE) with a core/shell structure are produced by a simple process. Magnetite nanoparticles (Fe 3 O 4 ) are coated with rare‐earth‐doped zinc oxide (ZnO). Core/shell structure is confirmed by high‐resolution transmission electron microscopy (HR‐TEM) analysis. X‐ray diffraction analysis results show that cubic magnetite Fe 3 O 4 and hexagonal ZnO phases originate from the core and the shell, respectively. Hexagonal ZnO and cubic magnetite Fe 3 O 4 phases belonging all nanoparticles are confirmed by HR‐TEM benefiting the lattice fringe. All the nanoparticles present superparamagnetic behavior. Under 532 nm excitation, they release the emission in the visible and infrared regions. They exhibit blue–green emission attributed to 2 H 11/2 – 4 I 15/2 , 4 S 3/2 – 4 I 15/2 transitions, red emission attributed to 4 F 9/2 – 4 I 15/2 transitions, and infrared emission ascribed to 4 F 9/2 – 4 I 15/2 , 2 F 7/2 – 2 F 5/2 transitions. Above the 0.2mol% dopant ratio, the luminescence intensity starts to decrease because of the concentration quenching. The produced nanoparticles are promising for bioimaging and magnetic hyperthermia treatment, due to their magnetic and luminescent properties, orientation to the target area, and their presence in the target area can be determined.