Glasses with the composition xV2O5-(15-x) Li2O-70B2O3-15ZnO, for x varies from 0 to 4 mol. %, were synthesized
using standard quenching technique. The amorphous nature for selected samples (x= 0, 1 and 4 mol. %)
was ensured from X-ray diffraction (XRD) measurements. The samples were found to compose mainly from BO3
and BO4 basic structural units as inferred from Fourier transform infrared (FTIR) data. The number of BO4 (BO3)
structural units was found to decrease (increase) with increasing the number of NBOs. These structural modifications
within the glass network are responsible for the here observed composition dependence optical energy
gap (Eotp) and Urbach band tail (ΔE). The electron spin resonance (ESR) results revealed a tetragonal
compression for VO2+ ions present in octahedral coordination, with distinct optical transitions in the visible
spectral regime. |
