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 are consisted of SiO2 core with a diameter of ~210 nm, GdPO4:Tb intermediate shell with thickness of ~7 nm, and SiO2 outer shell with thickness of ~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 (BSA) through a static quenching mode. The as-synthesized nanoparticles show great potential in biological cell imaging and cancer treatment.