Effects of Bi2O3 on optical Absorption , Ligand Field Parameters and structural Properties of Co2+ ion-doped lithium borate and lithium borosiicate glass systems

In the present study, the impact of bismuth cations on the constructional and optical characters of borate and borosilicate glasses containing Co (hybrid shaped glasses) was studied. Various glass specimens which have divergent quantites of Bi2O3 and a fixed quantity of CoO had been synthesized using a melt-quenching method. The physical properties of the synthesized compositions were examined in terms of density (p) and molar volume (Vm). The structural properties were investigated using infrared analysis and optical properties absorption spectroscopy. FT-IR studies revealed that Bi+3 ions cause structural rearrangements by converting tetra-coordinated boron into tri-coordinate boron, thereby increasing the number of non-bridging oxygen atoms (NBO). The observed decrease in the optical band gap energy is attributed to the increase in NBO which , in return has a noticeable deficiency in the optical band gap energy. The optical band gap energy was reduced; on the other hand the urabch energy grew up highlighting the significance of Bi2O3 in modifying the band gap and its localized states. The light absorption transitions of Co2+ ions were investigated using ligand field theory.