Structural properties of V2O5Li2OB2O3 glasses doped with copper oxide

Abstract

The optical transmission spectra in a wide range of wavenumbers: infrared (IR), visible and ultra-violet (UV) regions have been measured for lithium borate glasses of compositions x CuO:(3 − x )V 2 O 5 :37Li 2 O:60B 2 O 3 mol% (where x = 0.0–0.5). From the IR analysis, it was found that the different borate structural groups in these glasses are not affected by substitution of V 2 O 5 by small quantities of CuO. The UV visible results are analyzed with the aim of determining the optical energy gap, E opt , and the width of the localized states in the band gap. The values for E opt are found to decrease as CuO content increases. Substitution of V 2 O 5 by CuO creates additional localized states, due to Cu +2 , overlapping with that due to the matrix and extended to the mobility gap.