Structural and luminescence investigations of Gd³⁺ - Er³⁺ doped in lithium aluminum borate glasses using XANES and EXAFS techniques

The typical melt quenching technique was utilized to produce a possibly unique series of Gd³⁺ and Er³⁺ dual doped borate glasses with a composition of 25Li₂O–5Al₂O₃-XGd₂O₃-(69.0-X)B₂O₃-1.0Er₂O₃. The amorphous nature and information on chemical bindings of the materials were validated by using fundamental characterization techniques such as X-ray diffraction, Fourier transform infrared, X-ray absorption near-edge structure, and optical screening to identify their features (absorption, excitation, and emission). The refractive index of the glasses improves from 1.5487 to 1.628 as the concentration of Gd₂O₃ increases. The optical absorption spectra of Er³⁺ doped glasses were measured from the ultraviolet (UV) through the visible (Vis) and near infrared (NIR) ranges with varying Gd₂O₃ concentrations in order to determine their optical properties. This luminescence was found to be predominant in photoluminescence spectra, which were obtained at an optimum doping Gd₂O₃ concentration of 7.5 mol%. The impact of Er³⁺ doping was assessed through photoluminescence, which exhibited a broad, intense NIR band at 1537 nm ascribed to the ⁴I_13/2 → ⁴I_15/2 transition of Er³⁺ ions at λ_Ex = 486, 526, 651, and 978 nm excitation, which exhibits outstanding increased intensity with the Er³⁺ concentration until it reaches 1.0 mol %. A look at visible and near-infrared optical, it is observed that LAGd7.5BEr1.0 glass is a more potential candidate for photonic devices.