Judd-Ofelt Analysis and Emission Properties of Dy³⁺ Ions in Borogermanate Glasses

Borogermanate glasses singly doped with Dy³⁺ ions were synthesized and then studied using the absorption and luminescence spectra. Spectroscopic changes of Dy³⁺ ions have been examined for compositional-dependent glasses with various molar ratios GeO₂:B₂O₃. In this work, several spectroscopic parameters of Dy³⁺ ions were obtained experimentally and compared to the calculated values from the Judd-Ofelt theory. Luminescence spectra measured for borogermanate glasses consist of blue, yellow and red bands, which correspond to ⁴F_9/2 → ⁶H_15/2, ⁴F_9/2 → ⁶H_13/2 and ⁴F_9/2 → ⁶H_11/2 transitions of Dy³⁺, respectively. Luminescence lifetimes for the ⁴F_9/2 excited state are reduced, whereas the stimulated emission cross-sections for the most intense ⁴F_9/2 → ⁶H_13/2 yellow transition of Dy³⁺ increase with increasing GeO₂ and decreasing B₂O₃ concentrations in glass-hosts. Quantum efficiency of the ⁴F_9/2 (Dy³⁺) excited state is nearly independent on molar ratios GeO₂:B₂O₃. Attractive spectroscopic properties related to the ⁴F_9/2 → ⁶H_13/2 transition of Dy³⁺ ions are found for borogermanate glasses implying their potential utility for yellow laser action and solid-state lighting technology.