Double-perovskite Ca3TeO6:Sm3+, Na+ orange–red-emitting phosphors for UV-based white light-emitting diodes

A series of double-perovskite orange–red-emitting Ca (3−2 x ) Sm x Na x TeO 6 ( x  = 0.01–0.25) phosphors have been synthesized via high-temperature method. The single-phase and orthorhombic structure of Ca 3 TeO 6 :Sm 3+ , Na + phosphors was confirmed by X-ray powder diffraction. Under 405 nm excitation, Ca 3 TeO 6 :Sm 3+ , Na + phosphors emitted a series of orange–red emission due to the transition of Sm 3+ from 4 G 5/2 to 6 H J/2 ( J  = 5, 7, 9, and 11). The optimal Sm 3+ -doping concentration of Ca (3−2 x ) Sm x Na x TeO 6 ( x  = 0.01–0.25) was x  = 0.10. The thermal-quenching temperature of Ca 3 TeO 6 :0.10Sm 3+ , 0.10Na + phosphor was above 480 K. A white light-emitting diode (w-LED) based on 410 nm UV chip was successfully fabricated, and it presented a good correlated color temperature and a high color-rendering index (R a ). Therefore, orange–red-emitting Ca 3 TeO 6 :Sm 3+ , Na + phosphors have potential applications in UV-based w-LEDs.