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

摘要

In this paper, we construct core-shell structured nanoparticles, where magnetic Fe_2O_3 nanoparticles are used as the inner core and SiO_2 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 SiO_2 weakens the magnetic response of Fe_2O_3 core by showing a smaller coercivity value compared with that of pure Fe_2O_3 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.