White light emission in Tm3+/Er3+/Yb3+ tri-doped Y2O3 transparent ceramic

Tm3+/Er3+/Yb3+ triply doped Y2O3 transparent ceramics were fabricated by solid state reaction and characterized from the point of view of white light upconversion luminescence. All the samples exhibited high transparency not only in near-infrared band but also in visible region. Strong red (Er3+: 4F9/2 → 4I15/2), green (Er3+: 2H11/2, 4S3/2 → 4I15/2) and blue (Tm3+: 1G4 → 3H6) upconversion emissions have been observed under 980 nm excitation at room temperature. By varying the concentration of Er3+ ion, various colors of upconversion luminescence (pure blue, bluish green, pure green and yellowish green), including white light with CIE-X = 0.295 and CIE-Y = 0.312, can be easily achieved.