Structural and luminescent properties of the fluorine co-doped ZrO2:Y and ZrO2:Eu nanopowders

The results of calculations of the electronic band structure and experimental studies of zirconia (ZrO2) pure and doped with fluorine, fluorine/europium and fluorine/yttrium are reported. The incorporation of fluorine into polycrystalline zirconia was achieved by solid state synthesis. The studied powders were characterized by scanning electron microscopy, powder X-ray diffraction and luminescent spectroscopy. The samples were the mixture of the monoclinic and cubic zirconia polymorphs with a particle size distribution within 50-200 nm. Under excitation with 395 nm at T = 77 K, all the samples revealed intensive wideband host luminescence attributed to the F+ and F-0 luminescence centers. Zirconium dioxide doped with europium demonstrates a linear red emission of the Eu3+ ions in addition to the host photoluminescence. In the case of samples co-doped with fluorine and europium the emission intensity of the Eu3+ ions increased by about 8 times as compared to the ZrO2:Eu sample. The effect of fluorine on structural and optical properties of zirconia was discussed taking into account experimental data and results of calculations.