Down-conversion luminescence of Yb3+ in novel Ba4Y3F17:Yb:Ce solid solution by excitation of Ce3+ in UV spectral range

The down-conversion luminescence under UV excitation was demonstrated in single-phase Ba4Y3F17 solid so-lution nanoparticles codoped with Ce3+/Yb3+. The complex photodynamic processes occurred in the samples including excited state absorption, excitons and color centers formation. The Yb doping suppressed the solarization effect. The efficiency of down-conversion from UV to near IR luminescence of Yb3+ appeared to be high due to Ce4+-Yb2+ charge transfer mechanism responsible for energy transfer between Ce3+ and Yb3+ ions. The direct measurements of down-conversion luminescence quantum yield by means of integrating sphere and calculations of energy transfer efficiency from luminescence spectra data were carried out. The down-conversion luminescence quantum yield reached the maximum value of about 1% for the sample with 0,1 mol.% of Ce3+ and 5,0 mol.% of Yb3+ ions contents, whereas energy transfer coefficient reached its maximum of about 6,3% for 0,05 mol.% of Ce3+ and 5,0 mol.% of Yb3+ ions.