Red and green upconversion luminescence of Gd2O3 : Er3+, Yb3+ nanoparticles

Gd2O3:Er3+, Yb3+ nanoparticles have been synthesized by a homogeneous precipitation method with EDTA 2Na of two different concentrations. Upconversion luminescence spectra of the samples have been studied under 980 nm laser excitation. The results of XRD show that obtained Gd2O3:Er3+, Yb3+ nanoparticles are of a cubic structure. The average crystallite sizes could be calculated as 22 and 29 nm, respectively. The strong green and red upconversion emission were observed, and attributed to the H-2(11/2), S-4(3/2) -> I-4(15/2) and F-4(19/2) -> I-4(15/2) transitions of Er3+ ion, respectively