Structural and optical absorption coefficient analysis of barium lead sodium-borate glass doped with graphene nanopowder

In this study, some barium-lead sodium borate graphene-doped glasses have been prepared. The preparation is based on the concept of weight percentage using the fast quenching methodology. The internal phases of the as-prepared solid samples have been characterized using X-ray diffraction (XRD), and Fourier Transform Infrared (FTIR). All characterization processes revealed the amorphous nature of the as-prepared samples, with an increase in the crystallinity degree as the graphene content increased. On the other hand, the optical characterization was achieved using UV–vis, which revealed a decrease in both direct and indirect optical band gaps from 3.5 to 3.32 eV and from 2.95 to 2.66 eV, respectively, as the graphene content increased. The value of Urbach's energy decreased from 0.658 to 0.641 eV, which is an anomalous behavior because it is the same as that of the optical band gaps. At the same time, the decrease in the value of Urbach's energy confirmed the results of (XRD) about the crystallinity degree. The absorption coefficient spectra have been simulated using the hydrogenic excitonic model (HEM), where some useful parameters were obtained. Such parameters indicate the indirect optical transition as the dominant absorption mechanism, which is a common feature of amorphous solids. The obtained data suggested that graphene nanopowders as a modifier can be used to improve the effectiveness of oxide glasses for UV-blockers, radiation shielding, and greenhouse applications.