Optical absorption and FTIR studies of Cu2+ ion doped in 25Li2O-15BaO-(60-x) B2O3 glasses

Abstract

Glasses with composition 25Li2O-15BaO-(60-x) B2O3: x CuO (where x=0, 0.2, 0.4, 0.6, 0.8 and 1 mol %) were prepared using the conventional melt quench technique. The optical absorption spectra of studied glass samples show only one absorption band which is attributed to the 2B1g→2B2g characteristic transition of Cu2+ ions in the distorted octahedral sites. The cut-off wavelength (λc), optical band gap (Eopt) and Urbach energy (ΔE) were determined. The FTIR studies show different stretching and bending vibrations of alkaline earth lithium borate glasses. The relative variations in the intensities of BO3 and BO4 units in IR spectra with the concentration of CuO indicate that the copper ions mostly occupy modifying positions in the glass network when the concentration of CuO ≤ 0.8mol%.