Effect of grain size and concentration of active ions on structural and optical behavior of Eu3+-doped Y3Al5O12 nanocrystallites

The structural and luminescence properties of Y3Al5O12:Eu3+ (YAG:Eu3+; 0.2⩽xEu⩽5 mol %) powder materials prepared by the Pechini method were characterized by X-ray powder diffraction, Rietveld analysis and laser-excited photoluminescence. The formation of the pure garnet phase requires annealing at 800 °C but this temperature is decreased with increasing dopant concentration. The size of the nanocrystalline materials was found to increase from 20 to 67 nm with the annealing temperature from 800 to 1200 °C. Two possible reasons for the decrease in the size of the garnet unit cell with increasing annealing temperature were given. The composition and properties of various amorphous and intermediate phases were discussed mainly based on the luminescence of the Eu3+ ion. The (Y, Eu) solid solution was found to form irrespective of the Eu3+ concentration as indicated by the linear dependence of the garnet unit cell.