Structural and luminescent properties of Eu-ion-doped CaHfO₃

We investigated the structural and luminescent properties of Eu³⁺-doped CaHfO₃, which was synthesized using the solid-state reaction method. The crystal structures of the samples were analyzed by applying the Rietveld refinement technique on their X-ray diffraction patterns. Because of cation vacancies and/or interstitial oxygens, the unit-cell volumes of the samples increased, and the local lattice distortions were alleviated when the Eu³⁺ concentration increased. For near-ultraviolet photoexcitation, the emission spectra of our samples showed a series of narrow bands, which were assigned to the energy transitions of ⁵D₀ → ⁷F_J (J = 0, 1, 2, 3, and 4) in the Eu³⁺ ions. The luminescence behaviors of the samples were evaluated using Judd–Ofelt intensity parameters, which provided useful information regarding the local structure around the Eu³⁺ ions.