Luminescent silicate core–shell nanoparticles: Synthesis, functionalization, optical, and structural properties

SiO2/Zn2SiO4:Mn2+ core–shell nanoparticles with mean diameters in the range of 55–220 nm were prepared by a modified Pechini sol–gel method followed by lyophilization and annealing at temperatures of 800–1100 °C. The as-synthesized nanoparticles were characterized by transmission electron microscopy, X-ray diffraction analysis, and photoluminescence spectroscopy. The results demonstrate that the crystal structure of the shell and the optical properties can be tuned by the annealing temperature and a variation of the concentration of doping ions. Under UV excitation, the samples emit green luminescence with its maximum at 525 nm, typical for the Mn2+ ions in α-Zn2SiO4. The resulting nanoparticles were successfully modified with amine and carboxyl functions with respect to a later attachment of biological moieties.

Graphical abstractRedispersible luminescent SiO2/Zn2SiO4:Mn2+ core–shell nanoparticles with sizes in the range of 55–220 nmFigure optionsDownload full-size imageDownload high-quality image (88 K)Download as PowerPoint slideHighlights► Redispersible luminescent SiO2/Zn2SiO4:Mn2+ core–shell nanoparticles. ► Synthesis via sol–gel process followed by annealing at high temperatures. ► Adjustable particle sizes of 55–220 nm. ► Possibility to control the crystal structure and optical properties of nanoparticles. ► Surface modification in accordance with the intended application.