Structural and optical aspects for Eu3+ and Dy3+ ions in heavy metal glasses based on PbO–Ga2O3–XO2 (X = Te, Ge, Si)

Structural and optical properties of Eu3+ and Dy3+ ions in PbO–Ga2O3–XO2 (X = Te, Ge, Si) glasses have been examined using X-ray diffraction, FT-IR and luminescence spectroscopy. Several crystalline phases such as TeO2, PbTe3O7, PbO and PbO2 were identified in lead tellurite system using X-ray diffraction analysis, in contrast to PbO–Ga2O3–XO2 (X = Ge, Si) glass samples. Characteristic emission bands due to the 5D0 → 7FJ (J = 0–4) transitions of Eu3+ and the 4F9/2 → 6HJ/2 (J = 15, 13, 11) transitions of Dy3+ were registered. Two spectroscopic parameters, such as luminescence intensity ratios associated to 5D0 → 7F2 and 5D0 → 7F1 transitions of Eu3+ as well as 4F9/2 → 6H13/2 and 4F9/2 → 6H15/2 transitions of Dy3+, and luminescence lifetimes for excited states of rare earth ions were determined. The luminescence intensity ratios for Eu3+ and Dy3+ ions decrease, whereas 5D0 (Eu3+) and 4F9/2 (Dy3+) luminescence lifetime increases, when covalence between Ln3+ and O2− ions is reduced and the phonon energy of the host glass is increased in PbO–TeO2 → PbO–GeO2 → PbO–SiO2 direction. It was confirmed by FT-IR measurements.

► Structural and optical properties of Eu3+ and Dy3+ in heavy metal glasses were studied.
► Excitation and emission spectra of Eu3+ and Dy3+ in heavy metal glasses were detected.
► Luminescence intensity ratios R (Eu3+) and Y/B (Dy3+) and lifetimes were determined.
► Correlation between local structure and luminescence was obtained.