Judd–Ofelt parameters and X-ray irradiation results of MNb(2)O(6):Eu(3+) (M = Sr, Cd, Ni) phosphors synthesized via a molten salt method

Trivalent Eu-activated MNb(2)O(6) (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 Eu(3+) emissions with (5)F(0) → (7)F(j) transitions, and strong peaks occurred at the (5)D(0) → (7)F(2) transition. The PL and RL emissions of SrNb(2)O(6):Eu(3+) decreased over 3 mol%, while both emissions for CdNb(2)O(6):Eu(3+) and NiNb(2)O(6):Eu(3+) increased with increasing Eu(3+) concentration. The spectral properties of phosphors were evaluated by determining Judd–Ofelt intensity parameters (Ω(2), Ω(4)) from the PL emission spectrum. The quantum efficiencies (η(QE)%) of MNb(2)O(6):Eu(3+) (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 MNb(2)O(6):Eu(3+) (M = Sr, Cd, Ni) phosphors with highest emissions were found as follows; 24.182 × 10(−28), 28.674 × 10(−28), 38.647 × 10(−28) cm(3) and 20.441 × 10(−25), 13.790 × 10(−25), 3.987 × 10(−25) cm(2) s, respectively, corresponding to the (5)D(0) → (7)F(2) transition.