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 R (3) over bar 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 H-6(5/2) -> F-4(7/2). The optimum doping concentration of the Sr6LuAl(BO3)(6):xSm(3+) 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.