Improved luminescence in YVO4:Eu3+@YVO4 core-shell nanoparticles through surface-confined thermal diffusion of Eu3+

In this paper, we reported a type of highly luminescent YVO4:Eu3+@YVO4 core-shell nanoparticles (NPs) obtained by a surface-confined thermal diffusion method. YVO4:Eu3+ particle cores with a doping ratio of 50% were firstly synthesized, followed by the regrowth of pure YVO4 shells. Thereafter, the raw YVO4:Eu3+@YVO4 core-shell NPs were embedded into a silica xerogel, which underwent annealing at 800 °C for different times. Thanks to the protection of silica matrix and thermal diffusion of Eu3+, the as-obtained optimal NPs maintained the initial small size (19 nm), but exhibited considerably improved luminescent properties: the intensity was enhanced by 13 times and absolute quantum yield raised up to 14.4%. Such a good performance was interpreted by the corporation of three factors, i.e. improved crystallization, decreased concentration quenching and absent surface quenching.