High-efficient fabrication of core-shell-shell structured SiO₂@GdPO₄:Tb@SiO₂ nanoparticles with improved luminescence

SiO₂@GdPO₄:Tb@SiO₂ nanoparticles with core-shell-shell structure were successfully synthesized by a cheap silane coupling agent grafting method at room temperature. This method not only homogeneously coated rare-earth phosphate nanoparticles on the surface of silica spheres but also saved the use of rare-earth resources. The obtained nanoparticles consisted of SiO₂ core with a diameter of approximately 210 nm, GdPO₄:Tb intermediate shell with thickness of approximately 7 nm, and SiO₂ outer shell with thickness of approximately 20 nm. This unique core-shell-shell structured nanoparticles exhibited strong luminescence properties compared with GdPO₄:Tb nanoparticles. The core-shell-shell structured nanoparticles can effectively quench the intrinsic fluorescence of bovine serum albumin through a static quenching mode. The as-synthesized nanoparticles show great potential in biological cell imaging and cancer treatment.