National Research Tomsk State University, Tomsk, Russia:

L. N. Mishenina, Associate Professor at the Department of Inorganic Chemistry at the Faculty of Chemistry, Candidate of Chemical Sciences, e-mail: lnmishenina@gmail.com
A. Yu. Yagodina, Postgraduate Student at the Department of Inorganic Chemistry at the Faculty of Chemistry
L. A. Selyunina, Associate Professor at the Department of Inorganic Chemistry at the Faculty of Chemistry, Candidate of Chemical Sciences

Using citrate-nitrate sol gel method, the authors obtained yttrium orthoaluminate with a perovskite structure YAlO₃, as well as luminophors containing europium (III) ions Y_1–хEu_xAlO₃ (x = 0.01; 0.025; 0.050; 0.075; 0.1). The conducted study helped understand the dynamics of phase and structural transformations that take place during yttrium orthoaluminate synthesis. Methods of thermal and X-ray phase analysis were used to establish the key stages of the synthesis process, and the Rietveld method based on ReX Powder diffraction software was used for quantitative evaluation. At the final process stage, sol forms, which then converts into gel and, when dried, forms xerogel. Heat treatment of xerogel leads to the decomposition of the organic framework and production of gaseous products. The solid phase interaction that takes place during YAlO₃ synthesis involves stages at which yttrium – aluminium oxycarbonate Y₃Al₃O₈CO₃, as well as yttrium aluminates Y₄Al₂O₉ and Y₃Al₅O₁₂ form. Annealing at 1,300 ^oC for 7 hours enables to achieve the maximum concentration of orthoaluminate – i.e. 83% wt. Introduction of europium (III) ions stabilizes the perovskite structure, and the mass fraction of YAlO3 in the final product rises as the concentration of europium(III) ions rises. The maximum concentration of the target phase is 96 wt.%, achieved when 0.1 mol Eu³⁺ is introduced into the matrix. The surface morphology of yttrium aluminate was studied by scanning electron microscopy. Particles of similar grain size and shape can be obtained when conducting the synthesis at 1,300 ^oC. The authors examined the luminescence properties of yttrium orthoaluminate-based crystalline phosphors. Luminophors containing Eu³⁺ ions and having the following composition: Y_1–хEu_хAlO₃ (x = 0.01; 0.025; 0.050; 0.075; 0.1), emit red light, which is typical of Eu³⁺ in crystal matrices. The Y_0,9Eu_0,1AlO₃ luminophor has the maximum emitted intensity.

Support for this research was provided under the Development Programme of the Tomsk State University Priority 2030.

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