A novel orange–red emitting phosphor Sr₂LuTaO₆:Sm³⁺ for WLEDs

A novel double perovskite tantalite orange–red light emitting Sr₂LuTaO₆:Sm³⁺ phosphor was synthesized by the solid state reaction. The phase, crystal structure, photoluminescence properties, thermal stability and decay curves were studied. The X-ray diffraction patterns indicated that the phosphor has a pure phase of cubic phase structure. Excited by near-ultraviolet light at 407 nm, the sample exhibited three sharp emission peaks at 564 nm, 600 nm, 645 nm corresponding to the ⁴G_5/2 → ⁶H_J (J = 5/2, 7/2 and 9/2) transitions, respectively. The optimum doping concentration of Sm³⁺ ions was determined to be 5 mol% and the concentration quenching process comes from the energy transfer among nearest-neighbor ions. The as-prepared phosphors showed excellent thermal stability, the integral intensity at 423 K is about 91.10% of the initial intensity. The CIE chromaticity coordinates of Sr₂LuTaO₆:Sm³⁺ phosphors located in orange–red region. The results suggest that Sr₂LuTaO₆:Sm³⁺ phosphors have great potential application in white light-emitting diodes.