Optical spectroscopy of nanocrystalline cubic Y2O3:Er3+ obtained by combustion synthesis

Abstract

We report the emission and upconversion spectra and the lifetimes of Er³⁺ doped Y₂O₃ nanocrystalline and bulk samples. We found that when the nanocrystal and bulk samples of Y_1.80Er_0.20O₃ were excited at 815 nm, the overall emission intensity was stronger for the bulk sample. However, the relative intensity of the (²H_11/2, ⁴S_3/2)→⁴I_15/2/⁴F_9/2→⁴I_15/2 transitions is 2:3 and 3:2 for the nanocrystal and bulk sample, respectively. The decay times obtained for the nanocrystalline samples are in general significantly faster than those observed for the bulk sample. We attribute this to the adsorption of CO₂ on the surface of the nanocrystalline samples. The effect of Er³⁺ concentration on the decay time of the nanocrystalline samples is also discussed.