A comprehensive identification of optical transitions of cobalt ions in lithium borosilicate glasses

Exploring the materials with distinct optical properties is still in progress. Hence, Co-doped lithium borosilicate glasses of composition x Li2O-(80 - x) B2O3-19.6 SiO2-0.4 CoO (x = 5, 10, 15 and 20 mol%) were synthesized via communal melt quenching method. XRD affirmed the amorphous essence of such glasses. Local structure of such glasses was explored via FTIR spectroscopy. Simultaneously, the BO4 structural units in such glasses decreased with Li2O additions, rendering the open structure. Additionally, the density of such glasses decreased by Li2O addition, consequently, causing an open structure. The systematic substitution of B2O3 by Li2O affected the optical basicity and electronic polarizability of such glasses, causing the increase of NBOs ratio and ionic nature of such glasses. Interestingly, the optical transitions of Co-ions embedded in lithium borosilicate glass system were investigated. The optical band gaps provided lower values together with evident augmentation of band tails with Li(2)Oaddition. The processes of deconvolution and focusing of optical spectra were implemented on the characteristic bands of cobalt to obtain more visions into the crystal field interaction and d-levels splitting. The consequence of such processes revealed obvious reductions in the ligand field strength upon Li2O addition, leading to reduce d-levels splitting. Moreover, the metallization criterion values were changed from 0.41 to 0.37, rendering a semiconducting character to such glasses. Given the Co3+/Co2+ optical transitions in both visible and NIR spectral regions and their possible tunability through Li2O additives, such glasses are significantly useful for the development of optically active materials besides offering the prospect applications in various optical devices.