Synthesis, luminescence and crystallographic structure of Eu-doped garnet-type yafsoanite Ca3Te2(ZnO4)3

A red-emitting phosphor of Eu³⁺-doped calcium–tellurium–zinc oxide, Ca₃Te₂(ZnO₄)₃, with a garnet-type structure was synthesized by high temperature solid-state reactions. This phosphor exhibited a strong red emission. The photoluminescence excitation spectrum showed that Ca₃Te₂(ZnO₄)₃:Eu³⁺ can be effectively excited by UV–visible light. The property of long-wavelength excitation for this material has a benefit as a red phosphor in application of white light-emitting diodes. The colour coordinates were calculated. The excitation and emission spectra and luminescence decay curves were obtained using a pulsed, tunable, narrowband dye laser. Crystallographic sites and charge compensation mechanism of Eu³⁺ ions were discussed. The emission line from Eu³⁺ in intrinsic crystallographic site in the lattice was located at 579.56 nm. The emission line from Eu³⁺ in another disturbed site, which is created by the defects created by the charge-compensation, was located at 580.88 nm. The disordered crystallographic sites of Eu³⁺ are benefit for their strong red luminescence corresponding to the ⁵D₀→⁷F₂ transition.