Molten-salt synthesis and spectral characteristics of perovskite KCa2Nb3O10:Sm3+ phosphors

In this study, novel layered niobate KCa2Nb3O10:Sm3+ orange red phosphors have been successfully prepared by adopting the molten-salt method. The phase purity, surface morphology, photoluminescence properties, thermal stability, and fluorescence lifetime are systematically demonstrated. The X-ray diffraction (XRD) analysis revealed that these powders were pure phase and crystallized in an orthorhombic with a space group of Cmcm (No.63). Under 407 nm excitation, the KCa2Nb3O10:Sm3+ phosphors have the strongest emission peak at 603 nm which can be put down to the 6H5/2 → 4F7/2 transition of Sm3+. The optimum concentration of KCa2Nb3O10:xSm3+ is 5 mol%. The KCa2Nb3O10:Sm3+ phosphors display excellent thermostability because of their high T0.5 (over 480 K). Meanwhile, these samples show a high color purity from 96.6 to 98.2%. The white light-emitting diodes (w-LEDs) have been prepared with flying colors. All the results indicated that the potential application of the new kind of KCa2Nb3O10:Sm3+ luminescent powder in w-LEDs.