Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/98074
Title: Studies on Ag2O.MxOy.TeO2 (MxOy = WO3, MoO3, P2O5 and B2O3) ionic conducting glasses
Authors: Chowdari, B.V.R. 
Pramoda Kumari, P.
Keywords: Ionic conductivity
Raman spectroscopy
Tellurite glasses
XPS
Issue Date: 1-Dec-1998
Citation: Chowdari, B.V.R.,Pramoda Kumari, P. (1998-12-01). Studies on Ag2O.MxOy.TeO2 (MxOy = WO3, MoO3, P2O5 and B2O3) ionic conducting glasses. Solid State Ionics 113-115 : 665-675. ScholarBank@NUS Repository.
Abstract: Similarities and differences between the electrical, thermal and spectroscopic characterization results obtained by partial replacement of TeO2 by WO3, MoO3, P2O5 and B2O3 in the form of yAg2O.(1 - y)[xMxOy.(1 - x)TeO2] system are reported. It has been observed that the compositional variation of glass transition temperature is linear for WO3 and is non-linear for MoO3, P2O5 and B2O3 substitutions. Constituent dependency of conductivity at ambient temperature shows two maxima for tungsto-tellurite, molybdo-tellurite and phospho-tellurite glass systems while only a single maximum is observed for boro-tellurite glasses. From the individual X-ray photoelectron spectral analysis, it is found that tungsten exhibits two oxidation states whereas molybdenum, phosphate and borate are not reduced. The non-bridging oxygen atoms are distinguished from that of the bridging oxygen atoms by deconvoluting the O 1s XPS spectra. Raman spectroscopy shows that besides the expected TeO4 trigonal bipyramid, the TeO3 trigonal pyramid, the tungsten and molybdenum tetrahedra, the tungstate and molybdate octahedra, phosphate tetrahedra and borate triangles and tetrahedra are also present in tungsto-tellurite, molybdo-tellurite, phospho-tellurite and boro-tellurite glasses, respectively. The intensity ratios of the Raman peaks (I780/I660) may represent the ratio of the fractions of TeO3 tp and TeO4 tbp: (TeO3/TeO4). A good agreement is found for the fraction of TeO3/TeO4 obtained from both Raman and XPS studies. These results are correlated with those from conductivity and Tg studies. The unique crystallization behavior of these tellurite glasses were observed by the high temperature Raman spectral studies. © 1998 Published by Elsevier Science B.V. All rights reserved.
Source Title: Solid State Ionics
URI: http://scholarbank.nus.edu.sg/handle/10635/98074
ISSN: 01672738
Appears in Collections:Staff Publications

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