Structural, electrical, optical, and photoluminescence properties 20Li2O-(78-x)TeO2-xB2O3-1Er2O3-1Ag glasses
摘要
This study presents novel insights into the structural, DC conductivity, optical and photoluminescence properties of 20Li2O-(78-x)TeO2-xB2O3-1Er2O3-1Ag glasses prepared via the melt quenching method to investigate the influence of B2O3 content. XRD analysis depicted broad humps peaks that confirmed the amorphous nature of the glass system. Optical absorption analysis revealed that the optical band gap varies in the range of 3.39 − 3.53 eV, with a minimum at x = 7 mol%, which is attributed to an increase the presence of NBO units as illustrated in FTIR results. Notably, the DC conductivity (~ 10–6 S cm−1) exhibits a non-linear compositional dependence, decreasing at x = 7 mol% due to the increased contribution of BO3 units acting as stronger Coulomb traps, associated with the mixed glass former effect (MGFE). The UV–Vis NIR spectroscopy identified 10 absorption peaks centred at 1492, 977, 800, 653, 544, 521, 488, 451, 443, and 407 nm that corresponding to 4I13/2, 4I11/2, 4I9/2, 4F9/2, 4S3/2, 2H11/2, 4F7/2, 4F5/2, 4F3/2 and (2G,4F)9/2, respectively. The bonding parameter revealed predominantly ionic bonding in the glass system. An increase in oscillator strength at x = 9 mol% is due to the increase in covalency. Judd–Ofelt intensity revealed a decline in Ω2, indicating low covalency between Er3+ ions and ligand environment, while an increase in Ω6 correlated with higher BO content. The decrease in measured radiative lifetime (