Structural Elucidation of Eu(III)-Doped BaTiO3 Ceramics

Treball Final de Grau en Química. Codi: QU0943. Curs acadèmic: 2017/2018 BaTiO3 ceramics doped with Eu(III) were prepared via sol-gel synthesis with a Eu(III) content between 0 – 10 mol%. The nominal compositions of the prepared compounds were: (Ba1-3xEu2x)TiO3 and Ba(Ti1-xEux)O3-x/2, where two possible mechanisms of substitution are addressed. The environment of Eu(III) was studied from X-ray diffraction (XRD) data, scanning electronic microscopy (SEM), energy dispersive analysis of X-rays (EDX), and connecting both the optical properties (excitation, emission spectra, and decay curves) and the electrical properties (permittivity and impedance spectroscopy measurements). Regardless of the nominal compositions, the solubility limit of Eu(III) in the synthesised materials was found to be 2 – 3 mol%. Results were consistent with the occupation of Ba site until 2 mol% of Eu is reached in both mechanisms. It was also found for a 3 mol% in the Ba(Ti1-xEux)O3-x/2 mechanism that Eu occupies both Ba and Ti sites. Therefore, the combination of optical and electrical properties has led to a more accurately elucidation of Eu(III) in BaTiO3 ceramics.