Photoluminescence properties of a Dy3+, Na+-activated yafsoanite Ca3Zn3Te2O12 phosphor with excellent thermal stability

Novel yafsoanite yellow-emitting phosphors Ca(3−2x)DyxNaxZn3Te2O12 (x = 0.005, 0.01, 0.02, 0.05, 0.08, 0.10, and 0.15) were prepared via the traditional solid-state reaction at 1050 °C for 12 h in the air. The X-ray diffraction (XRD) pattern revealed that all the phosphors adopted garnet-typed yafsoanite structure. The photoluminescence spectra of Ca3Zn3Te2O12:Dy3+,Na+ phosphor exhibited an intense yellow-emitting emission, which indicated Dy3+ ions located at low symmetry sites in the Ca3Zn3Te2O12 host. The optimum concentration of Dy3+ was obtained to be 8%. Thermal quenching experiment showed that the PL intensity of Ca3Zn3Te2O12:0.08Dy3+,0.08Na+ phosphor can maintain 85% as heated up to 423 K compared to the initial one at room temperature. All the results showed that Ca3Zn3Te2O12:Dy3+,Na+ was a new kind of yellow emitting candidate for white LED (light-emitting diodes) applications.