The Influence of SiO2 Shell on Fluorescent Properties of LaF3:Nd3+ /SiO2 Core/Shell Nanoparticles

Distinct effects of the SiO2 shell on fluorescence properties of LaF3:Nd3+/SiO2 core/shell nanoparticles were demonstrated by annealling the nanoparticles at different temperatures. Emission spectra, excitation spectra, and decay curves of the nanoparticles were measured. A significant improvement of fluorescence intensity was observed for LaF3:Nd3+/SiO2 core/shell nanoparticles annealed at 900∘C. The phenomenon is ascribed to the change of environment of LaF3:Nd3+ core which is imposed by SiO2 shell. And the change is confirmed by the excitation spectra. It provides a useful way to improve fluorescent intensity of the SiO2-coated LaF3:Nd3+ nanoparticles. The lifetime for nanoparticles annealed at 900∘C shows a slight decrease contrast with nanoparticles annealed at 400 and 600∘C. This is caused by the higher phonon energy of SiO2 than that of LaF3