Judd–Ofelt parameters and X-ray irradiation results of MNb2O6:Eu3+ (M = Sr, Cd, Ni) phosphors synthesized via a molten salt method

Abstract

Trivalent Eu-activated MNb₂O₆ (M = Sr, Cd, Ni) ceramic phosphors were produced using the molten salt route, which involves a low sintering temperature and provides improved homogeneity. The photoluminescence (PL) and radioluminescence (RL) spectra of phosphors exhibited characteristic Eu³⁺ emissions with ⁵F₀ → ⁷F_j transitions, and strong peaks occurred at the ⁵D₀ → ⁷F₂ transition. The PL and RL emissions of SrNb₂O₆:Eu³⁺ decreased over 3 mol%, while both emissions for CdNb₂O₆:Eu³⁺ and NiNb₂O₆:Eu³⁺ increased with increasing Eu³⁺ concentration. The spectral properties of phosphors were evaluated by determining Judd–Ofelt intensity parameters (Ω₂, Ω₄) from the PL emission spectrum. The quantum efficiencies (η_QE%) of MNb₂O₆:Eu³⁺ (M = Sr, Cd, Ni) phosphors with the highest emission were found as 61.87%, 41.89%, and 11.87% respectively. Bandwidths (σ_e × Δλ_eff) and optical gains (σ_e × τ) of MNb₂O₆:Eu³⁺ (M = Sr, Cd, Ni) phosphors with highest emissions were found as follows; 24.182 × 10⁻²⁸, 28.674 × 10⁻²⁸, 38.647 × 10⁻²⁸ cm³ and 20.441 × 10⁻²⁵, 13.790 × 10⁻²⁵, 3.987 × 10⁻²⁵ cm² s, respectively, corresponding to the ⁵D₀ → ⁷F₂ transition.