Luminescence properties of Eu3+ ions in phosphate-based bioactive glasses

Eu2O3-doped phosphate-based bioactive glasses have been prepared by varying the calcium/potassium to phosphate ratio and their luminescence properties have been studied through absorption and emission spectra and decay rate analysis. Second and fourth rank crystal-field (CF) parameters and the CF strength parameters have been calculated by assuming the C2V symmetry for Eu3+ ions in the present glasses. Judd–Ofelt analysis has been used to derive radiative properties such as transition probabilities, branching ratios, radiative lifetimes and peak-stimulated emission cross-sections for 5D0 → 7FJ (J = 0–4) transitions. The relative luminescence intensity ratio of 5D0 → 7F2 and 5D0 → 7F1 transitions has been evaluated to estimate the local site symmetry around Eu3+ ions. The observed 5D0 → 7F0 transition for higher calcium content indicates two distinct sites for Eu3+ ion. Decay rates for the 5D0 level of Eu3+ ions in these glasses have been measured by monitoring the 5D0 → 7F2 transition. The lifetimes of the 5D0 level are found to decrease with increase in calcium contents.

Eu2O3-doped phosphate-based bioactive glasses have been prepared. The dependence of luminescence properties on glass composition has been studied and results show that covalence, asymmetry, lifetime, etc., have been affected significantly with different oxide network modifiers. Also from 5D0 → 7F0 emission, two sites have been noticed for higher calcium content (Ca30 glass). The figure shows emission spectra (5D0 → 7FJ) of the studied glasses.Figure optionsDownload as PowerPoint slide