Magnetic-downconversion luminescent bifunctional BaGdF5:Dy3+,Eu3+ nanospheres: energy transfer, multicolor luminescence and paramagnetic properties

Abstract

A series of Dy³⁺ or/and Eu³⁺ doped cubic BaGdF₅ phosphors were synthesized for the first time by an L-arginine hydrothermal method. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), photoluminescence spectroscopies (PL) and luminescence decay. The results indicate that the as-prepared samples are a pure cubic phase of BaGdF₅, taking on irregular nanoparticles with an average size of 20 nm. The as-prepared Dy³⁺ or Eu³⁺ single doped samples show strong blue and red emissions, originating from the ⁴F_9/2 → ⁶H_15/2 transition of the Dy³⁺ ions and the ⁵D₁ → ⁷F_J (J = 1, 2) and ⁵D₀ → ⁷F_J (J = 1, 2, 4) transition of the Eu³⁺ ions. Based on the rare earth concentrations and excitation wavelengths, multiple (white, red, blue and green yellow) emissions are obtained by Eu³⁺ ion co-activated BaGdF₅:Dy³⁺ phosphors. In addition, the energy migration from Dy³⁺ to Eu³⁺ has been reported in detail. Furthermore, the obtained samples also exhibit paramagnetic properties at room temperature and low temperature. It is obvious that Dy³⁺, Eu³⁺ co-doped BaGdF₅ nanomaterials with tunable multicolor emissions may have potential application in the field of full-color displays.