A study on optical, spectroscopic and structural properties of copper-doped calcium lithium borate glasses

In this work, the physical properties of calcium lithium borate glasses are investigated upon the inclusion of Cu+2 ion dopant. UV–Vis–NIR, photoluminescence, FTIR, and XRD techniques were, respectively, used in this study. From the optical absorption response of the samples, direct and indirect energy band gaps were calculated and they were found to be in the ranges of 3.57–3.28 eV and 3.78–3.6 eV, respectively. Results showed that the refractive index was increased from 2.258 to 2.326 with the increase in Cu2O concentration. Also, three main emission bands were observed in the luminescence spectra at around 399, 483, and 575 nm, which are correlated with the change in the copper concentration. Results of the FTIR spectroscopy showed various peaks in the ranges of 1383–1415 cm−1 and 1062–1076 cm−1, which can be attributed to the trigonal and tetrahedral stretching vibrations of BO3 and BO4 units.