Concentration dependent photoluminescence in Ce3+ doped Sr2SiO4 nanophosphor: role of lattice distortion and phase coexistence

Abstract

Sr₂SiO₄:xCe³⁺ nanophosphors were prepared by the sol-gel method and characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet reflectance spectroscopy, and photoluminescence spectroscopy. XRD analysis confirmed the presence of both α- and β-phases of Sr₂SiO₄, and that Ce³⁺ was successfully incorporated into the host matrix. Crystallite size and micro-strain were estimated, indicating short-range crystalline order with minimal lattice distortion. The excitation and emission spectra showed that the phosphors can be effectively excited at 271 nm and emit blue-green light with a peak at 468 nm, corresponding to the 5d→4f allowed transition of Ce³⁺ ions. The Ce³⁺ concentration quenching process was also investigated, and the mechanism was identified as a possible dipole-dipole transition. Additionally, zero phonon energy and Stokes shift were determined. CIE coordinates and colour purity were evaluated from the emission data. These preliminary findings indicate that the prepared Ce³⁺-doped nanophosphors are promising candidates for solid-state lighting applications, pending further studies of quantum yield and prototype devices.