Optical and Spectroscopic Features of K2B4O7-Li2B4O7 -TeO2 Glasses Modified with Cu2+ Ions

This work aims to analyze the structural properties of lithium and potassium tetra borate glasses that have undergone modification with tellurium oxide and Cu²⁺ ions with the chemical composition xK₂B₄O₇-(80-x) Li₂B₄O₇−19TeO₂−1CuO [KLTC] (with x = 50, 60, 70 & 80 mole%). The analysis is performed by using different spectroscopic methods. The absence of sharp Braggs peaks in the X-ray diffraction spectra confirmed the amorphous nature of the processed glasses. The optical parameter values were obtained from Tauc and Urbach plots. The band gap values decreased in proportion with the content of K₂B₄O₇ in KLTC. On these samples EPR studies were put on in order to determine the ligand field surrounded by the Cu²⁺ ions. The spin-Hamiltonian parameters suggest that the Cu²⁺ ions are located in tetragonally stretched octahedral locations. The existence of metal cations along with the characteristics borate as well as tellurite structural units were confirmed by the peaks observed in the Fourier transform infrared and Raman spectra. Among the prepared KLTC glass samples, KLTC-80 is found to be the best sample in the field of fiber optics communication.