Luminescent aerogels of Gd2O3:Eu3+ and Gd2O3:(Eu3+, Tb3+)

This study reports on the fabrication and characterization of luminescent aerogels of Gd2O3:Eu3+ and Gd2O3:(Eu3+, Tb3+), synthetized by the sol–gel method and the supercritical drying technique. The mol% concentration of the Eu3+ and Tb3+ ions in the synthesis were varied to study the effects of concentration on the luminescent properties of the aerogels. The results show that the Gd2O3:Eu3+ and the Gd2O3:(Eu3+, Tb3+) aerogels exhibited a maximum emission at λ = 613 nm. For all the samples, a decay in light intensity occurred when a concentration of 8 mol% of Eu3+ was exceeded, regardless of whether the Tb3+ ion was present. The analysis by X-ray diffraction showed that the aerogels of Gd2O3:Eu3+, like those of Gd2O3:(Eu3+, Tb3+), had a cubic crystalline structure with no change even at high concentrations of Eu3+. The microscopy analyses showed that the aerogels present a porous structure made up of interconnected quasi-spherical nanoparticles that formed a three-dimensional network. Quantum yield analysis shows that Tb3+ acts as a sensitizer of Eu3+, increasing the light intensity in the aerogels. The results reveal that it is possible to manufacture luminescent aerogels of rare-earth oxides that can be used in opto-electronic devices.