A New Blue-Emitting Oxohalide Phosphor Sr₄OCl₆:Eu²⁺ for Thermally Stable, Efficient White-Light-Emitting Devices under Near-UV

New blue-emitting Sr 4 OCl 6:Eu 2+ (SOC:Eu 2+ ) phosphor was prepared by solid-state reaction. Structural properties including phase purity were analyzed through Rietveld analysis, using X-ray powder diffraction. The photoluminescence (PL) property of the SOC:Eu 2+ phosphor was explored, for its successful application in the white light-emitting devices (WLED) industry. The SOC:Eu 2+ phosphor exhibits broad excitation spectra ranging from 250 to 425 nm, and an intense broad blue emission band centered at 446 nm under λ ex = 370 nm. The optimum concentration of Eu 2+ in Sr 4– x Eu x OCl 6 was found with x = 0.02 (0.5 mol %). The temperature-dependent PL studies have been investigated, and the phosphor exhibits strong thermal quenching resistance, retaining the luminance of ∼91% at 200 °C. The WLED device was fabricated by integrating the blue-emitting Sr 3.98 Eu 0.02 OCl 6 with commercial red- and green-emitting phosphor, excited with near UV LED chip (λ ex = 395 nm), and shows excellent CIE chromaticity coordinates ( x = 0.32, y = 0.33). The structural stability of the host, good thermal stability, and excellent CIE coordinates suggest that SOC:Eu 2+ is a promising blue component for application in the white LED industry.