Mixed alkali effect and optical properties of Ni2+ doped 20ZnO + xLi2O + (30 − x)Na2O + 50B2O3 glasses

Abstract Optical and physical properties of Ni 2+ doped 20ZnO +  x Li 2 O + (30 −  x )Na 2 O + 50B 2 O 3 (5 ≤  x  ≤ 25) glasses are carried out at room temperature. Powder XRD pattern of all the glass samples confirms the amorphous nature. Several physical parameters are evaluated for all the glasses with respect to the composition. The optical absorption spectra confirm the site symmetry of the Ni 2+ doped glasses are near octahedral. Crystal field and inter-electronic repulsion parameters are also evaluated. It is interesting to observe that the optical band gap and Urbach energies exhibit the mixed alkali effect. The FT-IR spectral investigations of Ni 2+ doped glasses exhibit characteristic vibrations of BO 3 and BO 4 units.