Analyzing of Judd-Ofelt parameters and radioluminescence results of SrNb2O6:Dy3+ phosphors synthesized via molten salt method

Dy3+ doped SrNb2O6 phosphors were fabricated by the molten salt process which avoids the high sintering temperatures, prolonged reaction time and poor compositional homogeneity. The crystal structure and morphology of samples were characterized by XRD (X-ray diffraction) and SEM (scanning electron microscopy). The PL (photoluminescence) and RL (radioluminescence) spectrums of SrNb2O6:Dy3+ phosphors exhibited strong blue emission peak at 576.0 nm which is related to the 4F9/2→6H15/2 transition of Dy. The high RL emission of 4F9/2→6H15/2 (electric dipole) transition with the X-ray excitation led to the decrease of Dy3+ local environmental symmetry. The Judd-Ofelt (J-O) theory was applied to the PL excitation spectra for the determination of optical data such as Ω2, Ω4, Ω6 parameters, radiative transition probability (Ar), branching ratio (β) and stimulated emission cross-section (σe). The quantum efficiency (ɳQE) for 3 mol% phosphor was found as 42.79%. The CIE chromaticity coordinates (x, y) and CCT (correlated color temperature) value for 3 mol% phosphor were found as (0.385, 0.432) and 4209 K, respectively.