Effects of Yb2O3 as Stabilizer and Sensitizer on the Luminescence Properties of Cubic ZrO2 Single Crystals

Large-size and high-quality stable ZrO2 single crystals containing x mol % Yb2O3 (x = 7, 8, 9, 10) (denoted as xYbSZ), and 8YbSZ crystals doped with 0.5 mol % Er2O3 were grown by the optical floating zone (OFZ) method. Yb3+ was indicated by XRD and Raman spectroscopy to have successfully entered into the ZrO2 lattice, which was stabilized in the cubic phase when the concentration of Yb2O3 was ≥8 mol %. Er3+ successfully entered the 8YbSZ lattice, and its spectral absorption intensity was enhanced compared to Er3+ in the corresponding yttria-stabilized zirconia (8YSZ), thus demonstrating that the Yb3+ ion has an excellent sensitizing effect on the up-conversion luminescence of Er3+. Fluorescence decay curves show that the up-conversion luminescence excited state lifetime of Er3+ is significantly enhanced in 8YbSZ compared to 8YSZ. Thus, these results demonstrate that Yb3+ ions not only successfully stabilize ZrO2 in the cubic phase structure but also maintain their role as an up-conversion luminescence sensitizer for Er3+ ions.