From Doping to Mixed Phases of Y2O3/Tb2O3 Powders

Today, yttrium oxide (Y2O3) and terbium oxide (Tb2O3) have many applications, mainly in technology and engineering, where they are used as phosphors, catalysts, magneto-optical materials, in ceramics and in fuel cells. However, one of the main challenges that arises when working with rare earth sesquioxides (RE2O3) is how to control and study the crystallographic structure of the compounds, since this directly influences the physical and chemical properties of the materials. For this article, ten different types of Y2O3/Tb2O3 powders were synthesized by the sol-gel process and heat treatment to determine how phase change occurs when the concentration of Tb2O3 in a Y2O3 matrix is increased and how this affects the photoluminescence of the material. The products obtained were subjected to photoluminescence, infrared spectroscopy (IR), and x-ray diffraction (XRD) to determine the effects of the phase mixture on their chemical, physical, and optical properties. After heat treatment at 800 °C, photoluminescence analysis revealed the presence of the main energy transitions 5D4-7FJ of the Tb3+ ion, mainly in the samples with low molar concentrations. Infrared spectroscopy revealed a single characteristic ν(M-O) band, located at about 560 cm−1. XRD revealed the presence of a preferential plane (222) associated with monoclinic structures. The main finding was that photoluminescence analysis and XRD through Rietveld analysis and crystallite size revealed the phase changes of the Y2O3/Tb2O3 system, ranging from the matrix to the doping phases, and finally, to a mixture of phases.