Structural, thermal, optical and photo-luminescent properties of barium tellurite glasses doped with rare-earth ions

- Structural, thermal and optical characterization of rare earth ion doped barium tellurite glasses.
- Tg depends on the bond enthalpy of modifier oxides and on the non-bridging oxygen concentration in the glass network.
- Conversion of TeO4 into TeO3 units on adding Ba2 + and rare earth ions.
- Eu3 + and Dy3 + doped barium tellurite glasses show strong luminescent peaks.
- Photoluminescence in glasses comparable to that in crystalline molybdate and tungstate phosphors.

BaO-TeO2 glasses containing 10 to 20-mol% BaO were studied by X-ray diffraction, density, thermal analysis, UV-visible and Raman spectroscopy. The effects of Eu3 +, Dy3 +, Er3 + and Nd3 + on the density, thermal, optical absorption and luminescent properties of barium tellurite glasses were studied. The short-range structure of barium tellurite glasses consists of TeO4 trigonal bipyramidal and TeO3 trigonal pyramidal units. TeO co-ordination (NTeO) was determined by Raman studies; it was found that that NTeO decreases with increase in BaO and rare earth oxide concentration. The glass transition temperature is a function of both the average single bond enthalpy and non-bridging oxygen concentration in the glass network. Glasses containing Dy3 + and Eu3 + show strong visible light photoluminescence, and our results show that barium tellurite glasses are suitable hosts for rare earth ion luminescence due to low phonon energies.