Thermally stable double-perovskite Ca3TeO6:Eu3+ red-emitting phosphors with high color purity.

A series of novel Eu3+-activated tellurate Ca (3-2x) Eu x Na x TeO 6 (x = 0.01–0.25) red-emitting phosphors were synthesized through a high-temperature solid-state route at 1220 °C. The phosphors were well crystallized in the space group P 2 1 /c (No. 14). Their photoluminescence emission and excitation spectra were investigated. The results indicate that the Ca 3 TeO 6 :Eu3+ phosphor can be effectively excited under 394 nm irradiation, which is suitable for UV LED chip. Upon 394 nm excitation, the Ca 3 TeO 6 :Eu3+ phosphor shows five peaks, corresponding to the 5D 0 –7F J (J = 0, 1, 2, 3 and 4) transitions of Eu3+. The optimal doping concentration of Eu3+ in Ca 3 TeO 6 : x Eu3+ was determined at 20 mol%. By temperature dependent emission spectra, the quenching temperature for Ca 3 TeO 6 :0.20Eu3+ was found to be over 500 K. The CIE chromaticity coordinates of Ca 3 TeO 6 :0.20Eu3+ are very close to the National Television System Committee (NTSC) standard red. [ABSTRACT FROM AUTHOR]