Journal of Fluorine Chemistry ( IF 1.9 ) Pub Date : 2018-04-16 , DOI: 10.1016/j.jfluchem.2018.04.008 S.V. Kuznetsov , O.A. Morozov , V.G. Gorieva , M.N. Mayakova , M.A. Marisov , V.V. Voronov , A.D. Yapryntsev , V.K. Ivanov , A.S. Nizamutdinov , V.V. Semashko , P.P. Fedorov
Praseodymium- and ytterbium-doped calcium fluoride powder samples were prepared by co-precipitation from aqueous solutions followed by annealing at 600 °C. Phase and microstructure analyses of these fluorite-type solid solution samples were carried out by X-ray diffraction (XRD) and scanning electron microscopy (SEM), which have demonstrated the average particle size to be about 30 nm, ∼100 nm after drying at 45 °C and annealing at 600 °C, respectively. The fluorescence studies under 443 nm excitation in 3H4 – 3P2 band of Pr3+ ions allowed us to determine the optimal chemical compositions of CaF2:Yb:Pr samples with the high Pr3+->Yb3+ energy transfer efficiency exceeding 90% and down-conversion luminescence efficiency up to 50%. The optimal compositions are: Yb:Pr = 10.0:0.05; 10.0:0.1; and 5.0:0.05 mol%. This confirms that the energy transfer from praseodymium to ytterbium occurred via quantum cutting mechanism, and the optimal composition for highly efficient phosphor application appears to be CaF2:Yb(10.0 mol%):Pr(0.1 mol%).