New solid solution ceramics LixY1-yEuy(VO4)1-xF4x (0
Résumé
New solid solutions, LixY(VO4)1-xF4x (0 < x ≤ 0.1), were successfully prepared via solid state reaction method by combination of orthovanadate YVO4 (Zircon structure) and LiYF4 fluoride (Scheelite structure). The structures were determined by X-ray diffraction and profil-matching refinements. Solid state nuclear magnetic resonance, Fourier transforms infrared and Raman spectroscopies with scanning electron microscopy were used to describe the microstructure and chemical composition of the as-prepared ceramics. It was found that solid solutions in the range 0 < x ≤ 0.1 are structurally similar to the zircon structure of YVO4. The luminescence properties of Eu3+ doped samples were investigated. Under excitation of 398 nm, the LixY1-yEuy(VO4)1-xF4x (x = 0.05, 0.07, 0.1; y = 0.05, 0.10, 0.15, 0.20) solid solution exhibited red emission originating from the strongest 5D0→7F2 transition. As the amount of Li+ and F− contents increases, the photoluminescence efficiency improved. So, the solid solution ceramics can be considered promising red phosphors for light-emitting diodes.