Influence of Zn2+ concentration on the luminescence properties of Dy3+ ions doped zinc strontium alumino-telluroborate glasses for light emitting applications

Incorporation of Zn2+ ions in the place of Sr2+ ions in a glass network and their concentration effect on the structural and spectroscopic properties of novel Dy3+ doped glass with composition (30-x)SrO+xZ-nO+39.5B(2)O(3)+25TeO(2)+5Al(2)O(3)+0.5Dy(2)O(3), (where x = 0, 5, 10, 15 and 20 wt %) have been investigated. The structural, bonding and spectroscopic changes due to the replacement of Sr2+ by Zn2+ ions were inspected through conventional routes such as FTIR, optical absorption, photoluminescence and lifetime measurements. Inclusion of Zn2+ ions into the glass medium affects the strength of Dy3+-ligand bonds and the Dy O bonds becomes less ionic with their surrounding ligands while increasing the Zn2+ ions concentration. Radiative properties of the Dy3+ ions emission transitions were derived using Judd-Ofelt (JO) theoretical framework and the increasing magnitude of Omega(2) parameters as increasing the Zn2+ ions concentration indicates that the symmetry around the Dy3+ ion sites in the glass network gets collapsed owing to the infusion of Zn2+ ions. Luminescence decay profile of the F-4(9/2) metastable state of the Dy3+ ions demonstrate the non-exponential nature and the same is fitted with Inokut-Hirayama (IH) model to identify the nature of interaction between the activators. It is found that the dipole-dipole interaction dominates between Dy3+ ions. Chromaticity color coordinates and CCT (color correlated temperature) values of the prepared glasses suggests that the current glasses are promising candidate for neutral white light emitting applications such as luminescence solar concentrators and bright white light emitting devices.