JUDD-OFELT ANALYSIS AND CONCENTRATION-DEPENDENT LUMINESCENCE QUENCHING BEHAVIOR OF Dy ³⁺ -DOPED NaYGeO ₄ PHOSPHORS PREPARED BY SOLID-STATE REACTION

In this study, a series of NaYGeO4 (NYG): Dy 3+ phosphors with varying Dy 3+ doping concentrations were successfully synthesized via a conventional high-temperature solid-state reaction method.X-ray diffraction analysis confirmed that all samples exhibited a pure NYG phase with no detectable secondary phases.To systematically investigate the concentration quenching behavior and thermal stability of luminescence, the photoluminescence properties of the samples were comprehensively characterized.In addition, diffuse reflectance spectra, fluorescence decay measurements, and Judd-Ofelt theory were employed to gain deeper insight into the optical transition characteristics of Dy 3+ ions.The results indicate that the internal quantum efficiency of the Dy 3+ 4 F9/2 level gradually decreases with increasing dopant concentration.