Facile hydrothermal synthesis and luminescent properties of Eu-doped CaF2–YF3 alkaline-earth ternary fluoride microspheres

Abstract

Large-scale CaF₂–YF₃ alkaline-earth ternary fluoride microspheres with diameters of about 2.5 μm were prepared by a facile hydrothermal method in the presence of disodium ethylenediamine tetraacetate (Na₂H₂L). The influences of several experimental parameters, such as reaction time, amount of Na₂H₂L, pH values, and fluoride source on the final products were investigated. The formation mechanism of the as-obtained microspheres was proposed on the basis of all these studies. It is also found that the addition amount of the Y³⁺ ions had an effect on the morphology of CaF₂–YF₃. The luminescence spectrum of Eu³⁺-doped CaF₂–YF₃ microspheres showed the strong characteristic dominant emission of the Eu³⁺ ions at 590 nm, indicating that the Eu³⁺ ions occupy a site of inversion symmetry in the CaF₂–YF₃ matrix.