Impurity doping: a novel strategy for selective synthesis of YF3 and NaYF4 crystals

Abstract

The phase conversions from YF₃ to α-NaYF₄, as well as α-NaYF₄ to β-NaYF₄ crystals, accompanied by morphology manipulation and upconversion (UC) luminescence enhancement have been demonstrated by simply increasing the Zn²⁺ ion doping concentration. We systematically discussed the influence of Zn²⁺ ion doping on the crystal phase and morphology of samples. Zn²⁺ ion occupies the Y³⁺ ion crystal lattice site leading to positive vacancy and lower energy barrier in the reaction of forming NaYF₄. Besides, we also investigated the UC luminescence intensity enhancement of β-NaYF₄:Yb/Er by Zn²⁺ ion doping. These results are expected to provide a new strategy for simultaneous phase control and remarkable UC luminescence enhancement of yttrium fluorides, which may be applicable for other fluorides.