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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.

Improved enzymatic activity and concentration-dependent selective activation of peroxidase and oxidase activity of combustion-synthesized nanoceria.

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The white light-emitting diode (WLED) is a state-of-the-art solid state technology, which has replaced conventional lighting systems due to its reduced energy consumption, its reliability, and long life. However, the WLED presents acute challenges in device engineering, due to its lack of color purity, efficacy, and thermal stability of the lighting devices. The prime cause for inadequacies in color purity and luminous efficiency is the spectral overlapping of red components with yellow/green emissions when generating white light by pumping a blue InGaN chip with yellow YAG:Ce³⁺ phosphor, where red phosphor is included, to compensate for deficiencies in the red region. An innovative strategy was formulated to resolve this spectral overlapping by alternatively arranging phosphor-in-glass (PiG) through cutting and reassembling the commercial red CaAlSiN₃:Eu²⁺ and green Lu₃Al₅O₁₂:Ce³⁺ PiG. PiGs were fabricated using glass frits with a low softening temperature of 600°C, which exhibited excellent thermal stability and high transparency, improving life time even at an operating temperature of 200°C. This strategy overcomes the spectral overlapping issue more efficiently than the randomly mixed and patented stacking design of multiple phosphors for a remote-type WLED. The protocol for the current design of PiG possesses excellent thermal and chemical stability with high luminous efficiency and color purity is an attempt to make smarter solid state lighting for high-powered remote-type white light-emitting devices.

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