Synthesis and structural characterization of Eu(III)-doped Zn7Sb2O12

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

In addition to the lanthanide series elements, Europium is one of the chemical elements of greatest interest for the development of species with oxidation state +3 (III), which leads to interesting electronic transitions. In a general sense, their emission spectrum lines are narrow and sensitive to effects of the ligand field around metallic ions. This property allows the use of Eu(III) as a structural probe. In this work, samples of semiconductor Zn7Sb2O12 and of solid solutions based on isoelectronically Eu(III)-doped Zn7Sb2O12 with stoichiometry Zn7-3xEu2xSb2O12 were prepared. Both Zn7Sb2O12 and Zn7-3xEu2xSb2O12 were synthesized via a chemical route using Pechini's method and characterized by Fourier transform infrared absorption vibrational spectroscopy (FTIR) and photoluminescence spectroscopy. In order to perform further spectral analyses, each spectrum was adjusted using a set of Gaussian functions. The FTIR spectrum analysis showed a slight band shift of the vibration mode assigned to the Sb-O bonding ascribed to the [SbO6] octahedron vibration. The theoretical fitting of the luminescence curves showed a broadening of the most intense emission peaks related to the transition Eu(III) D-5(0) -> F-7(2). As a whole, the results suggest that a less symmetric Eu(III) site occupation in inverse spinel structure may occur in sites close to the antimony octahedron, involving, however, non-substitutional site occupation.