Preparation and tunable luminescence of CaCO₃:Eu³⁺,Dy³⁺ phosphors

Phosphors based on calcium carbonate, co-doped with various Eu ³⁺ and Dy ³⁺ concentrations were prepared by microwave co-precipitation method. The prepared phosphors were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), thermogravimetry and differential scanning calorimetry (TG-DSC) and photoluminescence and photoluminescence excitation (PL-PLE) spectroscopy. Results showed that Dy ³⁺ and Eu ³⁺ ions were uniformly introduced into the host lattice of CaCO ₃ taking the place of Ca ²⁺ ions. Under the excitation at 382 nm, the emission peak wavelengths were at 487 nm (⁴ F _9/2 → ⁶ H _15/2 of Dy ³⁺), 576 nm (⁴ F _9/2 → ⁶ H _13/2 of Dy ³⁺), and 614 nm (⁵ D ₀ → ⁷ F ₂ of Eu ³⁺). The luminescent intensities and emitting colors of Eu ³⁺- Dy ³⁺ co-doped CaCO ₃ phosphors could be controlled by UV–violet excitations wavelengths or the rare-earth ions concentrations of Eu ³⁺ and Dy ³⁺ in phosphors. The chromaticity coordinates and photographs of samples under UV light showed the changes of the luminescence color intuitively through the varing UV–violet excitations wavelengths or the rare-earth ions concentrations of Eu ³⁺ and Dy ³⁺.