Concentration and temperature dependent fluorescent quenching and Judd-Ofelt analysis of Sm3+in Y4GeO8 phosphors

A range of Y4GeO8:Sm3+ phosphors featuring varying Sm3+ concentrations has been synthesized via high- temperature solid-state reaction method. Through X-ray diffraction (XRD) analysis, the crystalline structure of these phosphors was examined, confirming the purity of the Y4GeO8:Sm3+ phase. To study the concentration quenching and luminescence thermal stability of the Y4GeO8:Sm3+ phosphors, fluorescence spectroscopy was employed. Applying Van Uitert's model, it was demonstrated that the quadrupole-quadrupole interaction facilitates energy transfer among Sm3+ ions. Further insights into temperature-dependent fluorescence were gained, revealing that the Arrhenius-based crossover process accurately portrays the thermal quenching behavior of the 4G5/2 level for Sm3+ in Y4GeO8 powders. Lastly, leveraging the diffuse-diffraction spectrum and fluorescence decay curve, the optical transition characteristics of Sm3+ in the examined Y4GeO8 phosphors were analyzed in accordance with Judd-Ofelt theory.