Synthesis, luminescence and crystallographic structure of Eu3+-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.