Molten salt synthesis and spectral properties of Nd3+ doped CdNb2O6 columbite phosphors

Graphical abstract: Average decay times of the 4F3/2 emission as a function of temperature. Highlights: • Concentration quenching occurs in the high Nd3+concentration (6.0 mol%). • Lifetime of the 4F3/2 level is almost independent of temperature for 0.5 mol% Nd3+. • Lifetime of the 4F3/2 level increased with temperature for 3 and 6 mol% Nd3+. -- Abstract: Pure and Nd-doped CdNb2O6 particles have been prepared by a molten salt method using cadmium nitrate, niobium oxide and Li2SO4–Na2SO4 salt mixture as a flux at a relatively low temperature as compared to solid-state reaction method. X-ray diffraction patterns of the pure CdNb2O6 samples exhibited a single orthorhombic phase. Photoluminescence (PL) properties of all the undoped and Nd-doped samples in visible and near-infrared spectral region were studied in detail. While a strong blue emission band centered at 460 nm at room temperature was observed for the pure CdNb2O6, additional characteristic luminescence of Nd3+ at 1.06 μm was observed for Nd-doped CdNb2O6. Concentration quenching phenomenon was detected depending on the Nd-doping concentrations at both room and relatively low temperatures. This characteristic of the doped samples may be ascribed to the energy transfer between Nd3+ and niobate groups (NbO6)