Luminescent properties of Eu3+, Tb3+ or Bi3+ activated yttrium germanates

Preliminary studies were conducted on Eu3+, Tb3+ or Bi3+ doped Y2Ge2O7, Y2GeO5 and Y4GeO8 phosphors. Both photoluminescence and cathodoluminescent properties of the materials were measured. Among these materials, the luminescent intensities of Y2Ge2O7:Eu, Y2GeO5:Tb and Y2Ge2O7:Bi are relatively high and the luminescent colors of them are red, green and blue, respectively. In order to improve the luminescent properties for field emission display applications, further optimization is necessary. In addition, X-ray powder diffraction results indicate that Y4GeO8 phase forms in an orthorhombic unit cell, the parameters of which are: a=1.4976(5) nm, b=0.9357(6) nm, c=0.5885(3) nm, Vcell=0.82467(2) nm3.