White light luminophores based on Yb3+/Er3+/Tm3+-coactivated strontium fluoride powders

We have developed a synthetic protocol for the preparation of SrF2-based Yb3+/Er3+/Tm3+-coactivated nano-crystalline white light luminophores by co-precipitation from aqueous solutions and have achieved a good level of sample homogeneity in the course of their preparation. We established that the particle size and morphology of the precipitated nanopowders were essentially independent from the fluorinating reagent used, the starting materials' ratio and the conditions of thermal treatment. We achieved the target white light luminescence for Sr1−x(Yb/Er/Tm)xF2+x specimens with the best results obtained for the Sr0.785Yb0.200Er0.010Tm0.005F2.215 sample at 400 mW pumping power (λ = 974 nm).