Modified Sol-Gel Method of Synthesising a Mn4+-Doped Mg2TiO4: A Red Phosphor for Improved LED Performance

Abstract

Mn4+-doped perovskite Mg2TiO4 holds significant promise for the advancement of LED-based white light sources, given its cost-effectiveness, abundance, and stability at elevated temperatures. In this study, we present a novel approach employing the sol-gel method for the synthesis of Mg2TiO4:Mn4+ phosphor. Notably, the gel solution underwent a controlled cooling process at 2℃ for a complete day, resulting in reduced drying time, lower calcination temperature, shortened duration, and optimized concentrations of doped ions in the derived phosphors. We explore the influence of temperature and manganese ions on the crystal structure of the host material, and X-ray diffraction (XRD) analysis confirms the formation of a pure phase. Additionally, the X-ray energy dispersion spectroscopy (EDX) technique is employed to ascertain the compound's constituent proportions, revealing a crystallite size of 32.23nm. The photoluminescence study demonstrates an emission spectrum at 480 nm in the red region. Integrating our prepared red phosphor with a commercial yellow phosphor YAG:Ce3+, the resulting LED, utilizing a 450 nm blue chip InGaN, exhibits a correlated color temperature (CCT) of 4607 K, presenting a cool white color with chromaticity coordinates of x = 0.3594 and y = 0.3753. The modified sol-gel method thus offers a promising avenue for the efficient synthesis of Mn4+-doped Mg2TiO4 red phosphors, enhancing LED performance.