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SV Kuznetsov, OA Morozov, VG Gorieva… – Journal of Fluorine Chemistry 2018- Optics Letters, 2018

Abstract

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%).

 

 

… spectrophotometer. Fluorescence of the samples was performed with excitation by a 443 nm 10 ns laser pulse from OPO LT-2215(PC) laser systems produced by JV LOTIS TII and registered with Stellarnet spectrometer …