Photoluminescence and Structural Analysis of Eu³⁺-Doped Mg₄P₂O₇ and Ca₄P₂O₇ Nanophosphors for Red-Emitting Applications

Abstract

This study explores the synthesis, structural characterization, and photoluminescence properties of Eu³⁺-doped Mg₄P₂O₇ and Ca₄P₂O₇ nanophosphors. Utilizing glycine-assisted solution combustion and high-temperature solid-state methods, phase-pure and highly crystalline phosphors were developed. Structural features were investigated through X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The Mg₄P₂O₇:Eu³⁺ phosphor exhibited intense red emission centered at 615 nm under 395 nm excitation, corresponding to the ⁵D₀ → ⁷F₂ electric dipole transition. In contrast, Ca₄P₂O₇:Eu showed strong blue emission around 422 nm, attributed to the partial reduction of Eu³⁺ to Eu²⁺. Thermogravimetric analysis (TGA) confirmed excellent thermal stability, supporting the potential of these phosphors in white light-emitting diodes (w-LEDs) and optoelectronic devices.