Efficient energy transfer and tunable emission in NaLa(MoO4)(WO4): Tb3+/Eu3+ phosphors

Eu3+ and/or Tb3+ doped NaLa(MoO4)(WO4) phosphors were prepared via a combustion assisted route. The XRD patterns demonstrate that the Eu3+ and/or Tb3+ ions have been effectively doped into NaLa(MoO4)(WO4) host lattices. Under UV excitation, NaLa(MoO4)(WO4): Eu3+ samples exhibit a red emission corresponding to 5D0→7FJ (J=1, 2) transitions of Eu3+, while NaLa(MoO4)(WO4): Tb3+ samples exhibit characteristic emissions of Tb3+ (5D4→7FJ, J=3, 4, 5, 6). Tb3+ can effectively transfer excitation energy to Eu3+ under UV excitation when they are codoped in NaLa(MoO4)(WO4) host and the energy transfer mechanism is demonstrated to be the dipole-dipole interaction. The emission color of NaLa(MoO4)(WO4):0.4Tb3+,yEu3+ can be easily tuned from green through orange-yellow and ultimately to red by adjusting the Eu3+ content (y). These results indicated that NaLa(MoO4)(WO4): Tb3+/Eu3+ might be as a potential candidate as phosphors for visual display and solid-state lighting.