Effect of partial substituting Y3+ with Ln3+ (Ln = La, Gd) on photoluminescence enhancement in high-performance Na5Y(MoO4)4:Dy3+ white-emitting phosphors

White-emitting Na5Y1-yLny(MoO4)4:Dy3+ (Ln = La, Gd) phosphors were synthesized by a sol-combustion method. The effects of Ln3+ partial introduction on the structure and photoluminescence of Na5Y1-yLny(MoO4)4:Dy3+ (Ln = La, Gd) phosphors were studied. The X-ray diffraction and chemical composition results verified the successful introduction of Dy3+, La3+ and Gd3+ into the Na5Y(MoO4)4 lattice. Under the excitation of ultraviolet at 352 nm, the as-prepared phosphors showed a white emission with characteristic emission peaks at 577 nm (yellow) and 485 nm (blue), corresponding to the 4F9/2→6H13/2 and 4F9/2→6H15/2 transitions of Dy3+ ions, respectively. By substituting Y3+ ion with La3+ and Gd3+, the photoluminescence intensity of Na5Y(MoO4)4:Dy3+ sample was obviously enhanced due to the crystal field effect surrounding the luminescence center Dy3+. The chromaticity coordinates of all phosphors were located at the white light region, and the substitution of La3+ or Gd3+ could realize a higher color rendering index of white emission. Therefore, the as-prepared white-emitting Na5Y0.90La0.06(MoO4)4:0.04Dy3+ and Na5Y0.88Gd0.08(MoO4)4:0.04Dy3+ phosphors could be used as single-component phosphor for w-LEDs application.