Synthesis of Sr₆LuAl(BO₃)₆:Sm³⁺ Red Phosphor with Excellent Thermal Stability and Its Application in w-LEDs

In this study, a series of Sr₆LuAl(BO₃)₆:Sm³⁺ red phosphors were successfully prepared with a high-temperature solid-phase technology. The Rietveld refinement analysis of the X-ray diffraction (XRD) diffraction patterns indicated that the as-prepared phosphors belong to the R3¯ space group of the hexagonal crystal system. Under 404 nm near-ultraviolet excitation, the Sr₆LuAl(BO₃)₆:Sm³⁺ phosphor exhibits narrowband emission within the range of 550 to 750 nm. The primary emission peak is observed at a wavelength of 599 nm, corresponding to ⁶H_5/2 → ⁴F_7/2. The optimum doping concentration of the Sr₆LuAl(BO₃)₆:xSm³⁺ phosphor is 10 mol%. Nearest-neighbor ion interaction is the mechanism of concentration quenching. The synthesized phosphors demonstrate exceptional thermal stability, with a high quenching temperature (T_0.5 > 480 K). Furthermore, the assembled white light-emitting diode (w-LED) device exhibits a low color temperature (5464 K), an excellent color rendering index (R_a = 95.6), and CIE coordinates (0.333, 0.336) close to those of standard white light. Collectively, these results suggest the enormous potential of Sr₆LuAl(BO₃)₆:Sm³⁺ phosphors for applications in w-LEDs.