Ascendancy of iron ions on lithium ion conductivity, optical band gap, Urbach energy and topology of LiF-SrO-B2O3 glasses

Abstract

The transparent glass network 30LiF-10SrO-(60-x)B2O3-xFe2O3, is synthesized by melting quench technique, with 0 ≤ x ≤ 5 mol% (x = 0, 1, 2, 3, 4 and 5). These glasses are analyzed by X-ray diffraction (XRD), optical absorption, electron spin resonance (ESR), Fourier transform infrared (FTIR) studies and dielectric properties. Optical absorption spectra demonstrate a band at 446 nm corresponding to Fe3+ ions. Optical band gap of samples decreases with an increase in dopant. The intensity of ESR signal, at g ≈ 4 owing to rhombically distorted octahedral (FeO6) Fe3+ ions is raised up to 3 mol% of dopant and decreased at higher concentrations. FTIR displayed the conventional borate groups. A gradual increase is perceived in the dielectric variables like dielectric constant, ε′, dielectric loss, Tanδ, and a.c. conductivity, σac, with an increase in content of Fe2O3. All results suggest the gradual increase in semiconducting nature of glasses.