Luminescence properties of NaY(WO4)2:Sm3+, Eu3+ phosphors prepared by molten salt method

Sm3+ singly doped NaY(WO4)(2) and Sm3+, Sm3+ co-doped NaY(WO4)(2) phosphors have been synthesized by molten salt method. The crystal structure and morphology were characterized by means of X-ray powder diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). In Sm3+ singly doped NaY(WO4)(2) phosphors, the suitable doping concentration was proved. In Sm3+, Eu3+ co-doped NaY(WO4)(2) phosphors, the energy transfer from Sm3+ to Eu3+ is confirmed by the luminescent spectra. A strong absorption line at 405 nm can be generated from H-6(5/2)-K-4(11/2) (E-4(7/2)) transition of Sm3+ in Sm3+, Eu3+ co-doped NaY(WO4)(2) phosphors, which is suitable for the emission of the near-ultraviolet light-emitting diodes. The energy transfer efficiency, energy transfer rate and average distance between Sm3+ and Eu3+ in the NaY(WO4)(2):Sm3+, Eu3+ phosphors have been calculated based on the fluorescent dynamic analysis. Finally, the energy transfer mechanism between Sm3+ and Eu3+ is confirmed, the energy transfer occurs between (4)G(5/2) state of Sm3+ ions and D-5(0) state rather than D-5(1) state of Eu3+ ions. (C) 2015 Elsevier B.V. All rights reserved.