Double-perovskite Ca_3TeO_6:Sm~(3+), Na~+ orange-red-emitting phosphors for UV-based white light-emitting diodes

摘要

A series of double-perovskite orange-red-emitting Ca_((3-2x))Sm_xNa_xTeO_6 (x = 0.01-0.25) phosphors have been synthesized via high-temperature method. The single-phase and orthorhombic structure of Ca_3TeO_6∶Sm~(3+), Na~+ phosphors was confirmed by X-ray powder diffraction. Under 405 nm excitation, Ca3 TeO_6∶Sm~(3+), Na~+ phosphors emitted a series of orange-red emission due to the transition of Sm~(3+) from ~4G_(5/2) to ~6H_(J/2) (J = 5, 7, 9, and 11). The optimal Sm~(3+)-doping concentration of Ca_((3-2x))Sm_xNa_xTeO_6 (x = 0.01-0.25) was x = 0.10. The thermal-quenching temperature of Ca_3TeO_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_3TeO_6∶Sm~(3+), Na~+ phosphors have potential applications in UV-based w-LEDs.