Impact of Bismuth (Bi2O3) on physical and spectroscopic studies ZnO–Li2B4O7 glasses modified with Gd3+ ions

Abstract

The manuscript is to provide information about the preparation, identification of the glassy nature, primary physical parameters and structural studies of Bi2O3 – ZnO – Li2B4O7 – GdF3 glasses. The glasses of thickness around 1 mm were obtained by quenching the molten viscous material onto the moulds. These glasses are transparent enough to recognize them into glassy species but their amorphous nature was scientifically identified with peak free XRD spectra. Several properties like density, molar volume, optical absorption, FTIR, Raman and EPR spectra were measured, analyzed and discussed in detail. Density drastically increased from 2.7715 gm/cc (BZLG-0) to 4.9352 gm/cc (BZLG-40) nearly the increment is (Δρ = 2.1637 gm/cc) is attributed to the presence of bismuth. Molar volume declined to reach from 57.9366 (BZLG-0) to 56.5949 (BZLG-40) glass sample. Optical absorption spectra are flat with no absorption bands except edge transitions. With the concentration of bismuth going from low to high the optical band gap energy 3.281 eV (BZLG-0) shrinks to 2.825 eV (BZLG-40). The band gap decrement is associated with the formation of non-bridging oxygens. FTIR and Raman studies combinedly reveal the existence of certain structural groups and the domination of few borate modes. Observed EPR spectra have shown characteristic resonance signals of the so-called U spectrum typical for Gd3+ ions in disordered systems. In addition to the U-spectrum, an unexpected high crystal field resonance signal is also present.