Opto-Dielectric Properties of TeO2-Li2O-LiCl-Eu2O3 Glasses

Abstract

Europium oxide (Eu2O3) doped lithium tellurite glasses were prepared via melt quenching method. The effects of Eu2O3 doping at varying concentrations on the physical, electrical and optical properties of tellurite glasses were determined. The physical properties utilizing density and molar volume are determined. Electrical and dielectric constant in the 0.01–10 MHz frequency range was monitored as a function of temperature (298–398 K). At room temperature, the conductivity and activation energy increase with an increase in Eu2O3 concentration. Small polaron hopping (SPH) is used to explain the conduction mechanism. The density of the localized state is found to decrease with increasing Eu2O3 concentration in the range of 21.3 to 17.3 eV−1 cm−3. Dielectric parameters which are dielectric constant and loss tangent are found to increase with the increase in the concentration of Eu2O3. To study the spectroscopic properties of fabricated glasses, absorption and emission spectroscopy have been performed. UV–vis-NIR absorption spectra of glass samples divulged two significant peaks. Under the excitation of a 393 nm laser diode, six emission bands were observed in the Eu3+ single-doped glasses of which the peak at 613 nm corresponding to the transition 5D0 → 7F2 is highly intense for such glasses. Increasing intensity ratio ranging from 1.13 to 2.13 with increased Eu2O3 concentration is attributed to the low symmetry environment around Eu3+ ions. The findings of the current study can be used in advanced functional optoelectronic applications.