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(3−2x)SmxNaxTeO6 (x = 0.01–0.25) phosphors have been synthesized via high-temperature method. The single-phase and orthorhombic structure of Ca3TeO6:Sm3+, Na+ phosphors was confirmed by X-ray powder diffraction. Under 405 nm excitation, Ca3TeO6:Sm3+, Na+ phosphors emitted a series of orange–red emission due to the transition of Sm3+ from 4G5/2 to 6HJ/2 (J = 5, 7, 9, and 11). The optimal Sm3+-doping concentration of Ca(3−2x)SmxNaxTeO6 (x = 0.01–0.25) was x = 0.10. The thermal-quenching temperature of Ca3TeO6:0.10Sm3+, 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 (Ra). Therefore, orange–red-emitting Ca3TeO6:Sm3+, Na+ phosphors have potential applications in UV-based w-LEDs.