Magnetic–luminescent composite nanoparticles: Fabrication, characterization, magnetic and photophysical properties

In this paper, we construct core–shell structured nanoparticles, where magnetic Fe2O3 nanoparticles are used as the inner core and SiO2 doped with phosphorescent Ru(II) complex is used as the outer shell. The obtained magnetic–luminescent composite nanoparticles are identified and characterized by XRD analysis, IR spectrum, field-emission scanning electron microscopy, transmission electron microscopy, and fluorescence image, which confirms the core–shell structure. Then the magnetic and photophysical properties of the composite nanoparticles are investigated in detail. Data suggest that the outer shell of SiO2 weakens the magnetic response of Fe2O3 core by showing a smaller coercivity value compared with that of pure Fe2O3 nanoparticles. The composite nanoparticles are red-emitting ones, and the emission signal is sensitive towards oxygen concentration variations. However, the decreased excited state lifetime and weak emission of the Ru(II) emissive center limit the sensitivity.