Spectral studies on Cu2+ ions in sodium-lead borophosphate glasses

Electron Paramagnetic Resonance (EPR) and optical absorption spectra of Cu2+ ions in sodium-lead borophosphate glasses doped with different concentrations of Cu2+ ions have been studied. EPR spectra of all the glass samples exhibit resonance signals characteristic of Cu2+ ions. The values of spin-Hamiltonian parameters indicate that the Cu2+ ions in sodium-lead borophosphate glasses are present in octahedral sites with tetragonal distortion. The optical absorption spectra of all the glass samples show a single broad band, which has been assigned to the 2B1g→2B2g transition of Cu2+ ions. The optical band gap energy (Eopt) and Urbach energy (ΔE) are calculated from their ultraviolet absorption edges. The emission bands observed in the ultraviolet and blue region are attributed to 3d94s→3d10 triplet transition in Cu+ ion. The FT-IR spectra show that the glass system contains BO3, BO4 and PO4 structural units.