Influences of doping and annealing on the structural and photoluminescence properties of Y2O3 nanophosphors.

This paper reports the structural and optical properties of rare earth doped and codoped yttrium oxide nanophosphors. Dysprosium (Dy(3+)) and Terbium (Tb(3+)) doped and codoped yttrium oxide (Y2O3) phosphors were prepared by combustion synthesis method and subsequently annealed to high temperature to eliminate the hydroxyl group (-OH) and to get more crystallinity. The formation of compounds was confirmed by the X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR). The diffuse reflectance spectra (DRS) of doped and codoped Y2O3 powder phosphors were measured and it is observed that the absorption edge of the doped samples is shifted towards blue region with respect to undoped sample. The bandgap of the prepared samples were evaluated with the help of Kubelka-Munk function using Diffuse Reflectance Spectra (DRS) and an increase in bandgap was observed with the decrease in crystallite size. A strong characteristics emission from Tb(3+) and Dy(3+) ions was identified and the influence of doping concentration and annealing temperature on photoluminescence properties was systematically studied. Transfer of energy was observed in dysprosium-terbium codoped Y2O3 nanophosphor at room temperature from Dy(3+) ions to Tb(3+) ions.