Preparation and photoluminescence study of rare-earth-free red emitting La3Ga5SiO14:Mn4+phosphors

Given the growing interest in eco-friendly lighting solutions, the use of high-quality phosphors has become integral to the advancement of all-solid white light-emitting diodes (WLEDs). One novel phosphor, La₃Ga₅SiO${}_{14}$:Mn${}^{4+}$ (LGS), has been successfully synthesized via a high-temperature solid-state reaction. The crystal structure of LGS is classified as belonging to the trigonal phase, with a space group P321. The excitation spectrum exhibits a wide peak within the wavelength range of 280–440 nm. It emits a highly intense red light, with a peak emission occurring at 715 nm within the spectral range of 670–740 nm is attributed to the transition of Mn${}^{4+}$ from ⁴A${}_{2\mathrm{\text{g}}}$ to ⁴T${}_{2\mathrm{\text{g.}}}$ LGS:Mn${}^{4+}$ demonstrates a favorable quantum efficiency of 16% when doped with a concentration of 0.25 mol% Mn. The decay curve of LGS:Mn${}^{4+}$ exhibits a pattern of decreasing lifetime as the dopant concentration increases. Additionally, the LGS:Mn${}^{4+}$ products demonstrate a CIE chromaticity of (0.688, 0.2644), which is located within the deep red light region. All the aforementioned findings support the potential application of LGS:Mn${}^{4+}$ specimens in WLEDs, thereby contributing to the progress of environmentally friendly and energy-efficient lighting.