SYNTHESIS AND INVESTIGATION OF OPTICAL PROPERTIES OF EUROPIUM GALLATE PEROVSKITE STRUCTURE

EDN: KXWYQX

Abstract

Mixtures of hydrated oxides Eu₂O₃∙nH₂O and Ga₂O₃∙nH₂O were isolated from solutions of europium and gallium nitrates by the method of co-shrinkage. By subsequent calcination at 800 ^oC for 24 hours, europium gallate was obtained. The identification of the product was carried out by X-ray phase analysis and IR spectroscopy. Its structure has been found to correspond to the structural type of EuGaO₃ perovskite of orthorhombic symmetry (e.g. Pbnm, crystal lattice parameters: a = 0.5000 nm, b = 0.7565 nm, c = 0.5213 nm). A series of narrow bands characteristic of Eu³⁺ ions associated with ⁵D₀ → ⁷F_j transitions of 4f-electrons was registered in the luminescence spectrum of EuGaO₃. The stripes are inhomogeneously widened at the base with a weakly pronounced Stark structure. The most intense is the ⁵D₀ → ⁷F₂ doublet band of the electron transition with maxima located at wavelengths of 609 nm and 630 nm. The excitation of luminescence occurs as a result of the transfer of the energy of the phonon vibrational motion of the matrix to the excited levels of Eu³⁺ ions. A corresponding structured band was registered in the excitation spectrum at wavelengths < 350 nm. The short-wave part of the band is associated with the transition of 2p-electrons of O^2- ions to the 4f-orbital of europium ions in an oxide environment.