Study on molten salt synthesis, microstructural determination and white light emitting properties of CoNb2O6:Dy3+ phosphor

Abstract Undoped, 0.5, 3 and 6 mol% Dy 3+ doped CoNb 2 O 6 powders have been prepared by molten salt method using cobalt nitrate hexa hydrate, niobium oxide, dysprosium oxide and Li 2 SO 4 Na 2 SO 4 salt mixture as a flux at 800 °C for 4 h. X-ray diffraction patterns of the undoped, 0.5 and 3 mol% doped CoNb 2 O 6 samples exhibited a single orthorhombic columbite phase, while 6 mol% Dy 3+ doped powder showed minor phase. SEM-EDS results coonfirmed XRD findings and revealed smaller grain size by increasing Dy 3+ concentration. Structural and luminescence properties of Dy 3+ doped samples in UV–vis spectral region were studied. The emissions increased with increasing doping concentration up to 3 mol%, and then decreased due to concentration quenching effect. The color chromaticity temperature (CCT) data of all samples have been estimated in white light region and color of light appear close to yellowish-green.