Nanocomposites and nanomaterials

Luminescent properties of Europium (III) acetate monohydrate in the pores of synthetic opal
Ohiienko O.V., Moiseyenko V.N., Shvets T.V. 
Physics, Electronics and Computer Systems Department, Oles Honchar Dnipro National University. Prospect Gagarina, 72, Dnipro-49010, Ukraine. 
E-mail: vnmois@ukr.net

The photoluminescence spectra of the trivalent europium ion (Eu3+) have been the subject of extensive studies [1]. Of particular interest is the luminescence of europium ions in the composition of europium (III) complexes with organic ligands, which absorb the excitation light and to transfer the excitation energy to the Eu3+ ion.
This paper is devoted to the study of the influence of the environment of the europium ion in the structure of salt Europium (III) acetate monohydrate (C6H9EuO6×H2O) in the pores of the opal matrix on the photoluminescence spectra. The change in the environment of the europium ion was carried out by thermal annealing of opal samples with salt in pores at different temperatures in the range of 40-1000°C. For comparison, a similar procedure was carried out for the original salt. We obtained photoluminescence spectra of the salt C6H9EuO6×H2O after thermal annealing at temperatures in the vicinity of the anomalies on the TGA and DTA curves presented in the work [2]. The excitation of the opal samples was carried out in the "reflection" geometry from the (111) plane by the radiation of a semiconductor laser with λex=405nm. The luminescence spectra of the initial salt and salt in the pores of opals demonstrate high intensity radiative transitions: 5D0→7F0, 5D0→7F1, 5D0→7F2. The regularities of the changes in the characteristic’s photoluminescence spectra for the original salt as well as for the salt in the bulk opal pores were studied. Compared with the original salt, for salt in the opal pores, mild splitting of the luminescent bands is observed. With an increase in annealing temperatures above 270°C, the luminescence spectra of the initial salt and salt in the opal pores show a significant decrease and change in the spectral intensity distribution due to dehydration and subsequent decomposition of salt to Eu2O3 [2].

1.	Binnemans K. Interpretation of europium (III) spectra // Coordination Chemistry Reviews.-2015.-295.-P. 1-45.
2.	Basma A.A. Balboul, Mohamed I. Zaki Thermal decomposition course of Eu(CH3COO)3·4H2O and the reactivity at the gas/solid interface thus established // Journal of Analytical and Applied Pyrolysis.-2011.-92.-P. 137-142.