The synthesis and luminescent properties of novel water-soluble CaF2:Tb3+ nanoparticles

Novel water-soluble CaF2:Tb3+ nanoparticles were synthesized using benzoimidazole-5-carboxylic acid (Ligand) as surfactant. The particle size of the nanoparticles is below 10 nm. The investigation of fluorescence properties showed that there exists energy transfer from the surface coating of nanoparticles to Tb3+ leading to the sensitized fluorescence emission of Tb3+. The luminescence lifetimes of Tb3+ were 937.56 μs (37.41%) and 2.78 ms (62.59%). It is more important that Cu2+ and Fe3+ can give rise to emission quenching to the Tb3+ of nanoparticles, especially Cu2+. In the region of 2.5×10−5-5×10−4 M, the higher the concentration of Cu2+ or Fe3+ is, the stronger fluorescence quenching to the Tb3+ is. Additionally, the possible mechanisms of the luminescence quenching were also discussed.