SÍNTESE E CARACTERIZAÇÃO DE VIDROS CÁLCIO BOROTELURETOS DOPADOS COM Eu2O3 SINTETIZADOS EM ATMOSFERA DE ARGÔNIO

Abstract

In this study, glasses of Calcium Borotellurite (CaBTe) doped with Eu2O3 were synthesized in an argon atmosphere with the aim of examining the influence of TeO2 concentration on structural, thermal, optical, and spectroscopic properties. Additionally, the impact of the argon atmosphere on the valence change of the europium ion was investigated. The results were discussed in relation to the TeO2 content. The adopted composition was 10CaF2 – (29.5 – 0.4x)CaO – (60 – 0.6x)B2O3 – xTeO2 – 0.5Eu2O3, with x = 10, 16, 22, and 31% in mol; the glasses were prepared using the melt-quenching method. X-ray diffraction results indicate that the samples studied in this work have an amorphous nature. Fourier-transform infrared spectroscopy results show that the vitreous network is formed by the TeO3, TeO4, BO3, and BO4 structures. Differential thermal analysis results showed a decrease in the glass transition temperature with increasing TeO2, and good thermal stability within the margin of error. Refractive index results increased with the rise in TeO2 content. In the results of the optical absorption coefficient, strong absorption in the ultraviolet region was observed; the argon atmosphere was not efficient in reducing Eu3+ to Eu2+, and a shift in the absorption edge to longer wavelengths occurred with the increase of TeO2. Luminescence results showed that the Eu3+ doped CaBTe glass is a good luminescent source. In the chromaticity diagram, a predominance of the color red was observed for all samples. In the lifetime results, a decrease was observed with the increase of TeO2.