Preparation of fluorides at 80 °C in the NaF-(Y, Yb, Pr)F3 system

Crystalline single-phase hexagonal fluorides with nominal compositions NaY 1–x–y Yb x Pr y F 4 (with 0≤x≤1 and y≤0.05) have been prepared by a coprecipitation technique without the need of any thermal treatment as a final step. Compared with the fluorides prepared by solid state chemistry, this protocol allows better control of the stoichiometry of the materials and improves the homogeneity of the grain size distribution. The influence of these structural and microstructural parameters and of the oxygen content on the optical performances of these fluorides is examined and discussed by comparison with the spectroscopic properties of solid state synthesized Pr 3+ -doped NaYF 4 fluorides.