White light luminescence in Dy/Tm co-doped yttria stabilized zirconia single crystals

A series of high quality Dy_(2)O_(3) and Tm_(2)O_(3)co-doped yttria stabilized zirconia(YSZ) single crystals was synthesized.These crystals have a single cubic structure,and exhibit the characteristic of Dy^(3+)(blue and yellow emissions) and Tm^(3+)(blue emission) under excitation with NUV light.Impo rtantly,the hue can be varied between blue and white by modifying the Tm^(3+)/Dy^(3+)ratio.The photoluminescence and decay curves are consistent with the existence of resonance-type energy transfer from Tm^(3+)to Dy^(3+)ions via an electric multipole interaction mechanism.Maximum luminescence intensity is observed in YSZ doped with 0.50 mol% Tm_(2)O_(3) and 0.75 mol% Dy_(2)O_(3),and this sample has CIE coordinates(x = 0.33,y = 0.33) in accordance with those for white chromaticity.Thus,the outstanding luminescence properties of these single crystals suggest potential applications in white light emission devices.