Development of High-Efficiency BaSrCaWO₆:Mn⁴⁺ Red-Emitting Phosphors via La³⁺ Addition Strategy

In this paper, a series of BaSrCaWO₆:x%Mn⁴⁺, y%La³⁺ (x = 0.1, 0.5, 0.6, 1.5; y = 0, 5, 10, 15, 20) red-emitting phosphors were synthesized by the high-temperature solid-state method. The structure and optical properties of the samples were systematically studied by the characterizations of x-ray diffraction (XRD), scanning electron microscope (SEM), UV-Vis spectra, photoluminescence (PL) spectra, photoluminescence excitation (PLE) spectra, and quantum efficiency (QE). It was found that the addition of La³⁺ ions plays significant roles on the luminous performance of phosphors as compared with the nonluminous BaSrCaWO₆:Mn (BSCW:Mn), which can be attributed to the Mn²⁺ → Mn⁴⁺ oxidation process induced by La³⁺ doping. The BSCW:0.5%Mn, 15%La³⁺ phosphor exhibited a strong emission peak at 685 nm with a CIE chromaticity coordinate at (0.720, 0.279), which is suitable for application in indoor plant cultivations. The BSCW:0.5%Mn, 15%La³⁺ phosphor exhibited an IQE of 47.8% and a high absorption efficiency of 72.8% with the EQE of 34.8%. Besides, the phosphor also showed the thermal stability with the emission intensity at 423 K being 48% of the emission intensity at 298 K. These results indicate that the synthesized BSCW:0.5%Mn, 15%La³⁺ phosphor could be a potential phosphor to be applied in plant growth LEDs.