Synthesis and Luminescence of Europium-Containing Compositions Based on Yttrium and Aluminum Oxides

Europium-containing composites based on yttrium and aluminum oxides were obtained by thermal destruction of a mixture of poorly soluble metal hydroxoforms at temperatures of 700, 800, and 900°C for periods of 3, 6, and 9 h. These compounds, in turn, were synthesized by the reaction of metal nitrate salts with ammonia in an aqueous solution. The synthesis products were identified using X-ray powder diffraction, vibrational and electron spectroscopy, and electron microscopy with microprobe analysis and their luminescent properties were studied. It was shown that, at a synthesis temperature of 900°C for 9 h, the main components of the composite matrix were yttrium aluminates Y3Al5O12 (YAG) and Y4Al2O9 (YAM). The luminescence of the activated composites is associated with 5D0.1→7Fj electron transitions of Eu3+ ions. Its intensity increases linearly with increasing Eu3+ concentration to 10 at %. Luminescence excitation occurs predominantly at wavelengths <300 nm. It is associated with the sensitization transfer of vibrational energy from the oxide matrix, as well as with the transitions of oxygen valence electrons to the orbitals of Eu3+ ions. The obtained results can be used to synthesize luminescent compositions with predictable spectral properties for use as compact UV radiation sensors.