Thermal, structural and spectroscopic investigations on Eu3+ doped boro-tellurite glasses

Eu3+ doped boro-tellurite glasses with the chemical composition (69 − x)B2O3–xTeO2–15Mg2O–15K2O–1Eu2O3 (where x = 0, 10, 20, 30 and 40 wt%) have been synthesized and its thermal, structural and spectroscopic behavior were studied and reported. The thermal behavior of the Eu3+ doped boro-tellurite glasses were explored through DTA thermograms. The presence of varying tellurium dioxide results in structural and spectroscopic changes around Eu3+ ions and are explored through XRD, FTIR, UV–vis, Luminescence and lifetime measurements. The XRD pattern confirms the amorphous nature and the FTIR spectra reveal the formation of the local structural units BO3 and BO4 in the prepared glasses. The bonding parameters (̄β and δ) have been calculated based on the observed band positions of the absorption spectra. The Judd–Ofelt (JO) parameters were determined from the absorption and luminescence spectra and the results are presented. The variation in the JO intensity parameters Ωλ (λ = 2, 4 and 6) and the hypersensitive band positions with the change in chemical composition have been discussed in detail. The JO parameters have been used to derive important radiative properties like transition probabilities (A), branching ratios (βR) and peak stimulated emission cross section (σE/P) for the 5D0 → 7FJ (J = 1, 2, 3 and 4) transitions of the Eu3+ ions. The varying optical properties of the prepared glasses with the change in tellurium dioxide have been studied and compared with similar results.

► Fundamental O–H, (BO3)− vibrations and B–O–B linkages in borate network explored.
► The covalent nature of the Eu3+ ions with surrounding ligands have been confirmed.
► B3TMK glass is found to be the best optical candidate for laser working at 612 nm.