Synthesis and luminescence properties of La2Zr2O7:R (R = Sm3+, Bi3+, Sm3+/Bi3+) phosphor

Le(2)Zr(2)O(7):R (R = Sm-3(+), Bi3+, Sm3+/Bi3+) phosphors are synthesized by solid-state reaction method in air. Blue emission band peaking at similar to 462 nm of La2Zr2O7:Bi-3+ phosphor with excitation at 312 nm is observed in the range of 370-610 nm due to P-3(1 )-> S-1(0) transition of Bi3+ ion and D -> S-1(0) transition between Bi-3+ and Zr4+ ions. Le(2)Zr(2)O(7):Sm-3(+) phosphor with excitation at 407 nm shows reddish orange light in the range of 550-750 nm owing to (4)G(5/2) -> H-6(J) (J = 5/2, 7/2, 9/2, and 11/2) transitions of Sm3+ ion. Tunable emission from blue to white of Le(2)Zr(2)O(7):Sm3+, Bi3+ phosphor with excitation at 312 nm can be observed due to the changing Bi-3(+) or Sm3+ ion concentration. Le(2)Zr(2)O(7):Sm3+, Bi3+ phosphor with excitation at 407 nm only emits reddish orange because Bi 3+ has no absorption at 407 nm. The energy transfer from Bi3+ to Sm3+ is discussed. The luminous mechanism is explained by the energy level diagrams of Bi3+ and Sm3+ ions.