Structural, and optical characterizations of Cu/Fe@Na₂B₄O₇ oxide glass: For shielding and optical applications

This work has been set up to estimate how the structural, and optical properties of the copper sodium borate-based glass change when the low bandgap oxide Cu₂O₃ is replaced by the one of the highest bandgap of Fe₂O₃. Where the value of the optical band gap of Cu₂O₃ (1.25–1.33 eV) is one half that of Fe₂O₃ (2.2 eV), approximately. Using the traditional fast quenching method, three categories of solid samples have been obtained, copper-free (one sample), iron-free (one sample), and copper-iron-doped (three samples). X-ray diffraction (XRD), Transmission electron microscopes (TEM), Fourier transform infrared (FTIR), and ultraviolet-visible (UV–Vis.) spectra have been used for structural and optical characterization. XED exhibited an amorphous nature for all the prepared samples, while the FTIR showed an increase in the number of the nonbridging oxygen atoms as a result of conversion from BO₃ into BO₄. Also, FTIR showed that Fe- cations occupied the interstitial spaces as FeO₆. The Photoluminescence PL emission showed two emission peaks due to Fe^{2+, 3+} and Cu^{2+, 3+} multi-valence cations. The metallization factor, bulk density, and the optical band gaps increased when Cu₂O₃ was replaced by Fe₂O₃, with an increase in the values of the molar volume and the linear refractive index. Shielding parameter Z_eff referred that the Fe-Free sample is more suitable for shielding applications than the Cu-Free sample, at low energies.