Síntese e estudo das propriedades estruturais, térmicas, ópticas e espectroscópicas dos vidros cálcio boroteluretos dopados com Er2O3

Abstract

The synthesis, structural, thermal optical and spectroscopic properties of calcium borotellurite erbium trivalent (Er3+) doped glasses are investigated in this study. The samples composition follows the equation 10CaF2 – (29.9-0.4x)CaO – (60-0.6x)B2O3 –xTeO2 – 0.1Er2O3, x = 10, 16, 22, 30 and 50 mol%, and the melt-quenching (in air) method were used. X-ray diffraction, density, refraction index, luminescence, optical absorption, lifetime, DTA and specific heat measurements were carried out and the molar volume (Vm) and the electronic polarizability were calculed (αm) The results are discussed in terms of tellurium oxide content. Samples were successfully synthesized and the results of X-ray diffraction proved the amorphous character of the structure. It was observed increasing values of density, molar volume, refractive index and electronic polarizability as consequence of the TeO2 adding. The spectroscopy Raman and FTIR presented the TeO3, TeO3+1, TeO4, BO4, BO3, boroxol ring, pyro-, meta- and orthoborate groups. The increasing content of TeO2 results in an increase of NBO’s. The thermal analysis shows a decrease in the glass transition temperature (Tg), crystallization temperature (Tx) and specific heat with the increase of TeO2 content. All samples presented good thermal stability, according to Hrubý parameter, with οT > 100 °C. The optical band gap energy decreases with the increase of TeO2 due to the increase of nonbridging oxygens (NBO’s) units. Luminescence intensity and radiative lifetimes at 1530 nm show increases with the TeO2 content. Such behavior is associated with the reduction of hydroxyl groups and network phonon energy. The calcium borotellurite Er3+ doped glasses, named Er:CaBTeX, presented properties promising in photonics devices application.