Thermal, electrical and XPS studies of Ag2O · TeO2 · P2O5 glasses

Abstract

A series of silver ion conducting glasses have been synthesized by progressive replacement of P2O5 by TeO2 in the 0.50 Ag2O · 0.50[xTeO2 · (1 - x)P2O5] system. A wide glass-forming region extending from x = 0 to x = 0.9 was found. The glass of composition corresponding to x = 0.4 was found to have the highest Tg = 196.7 ± 0.1°C. The ionic conductivity was found to increase by about two orders of magnitude with increase in TeO2 content. While σ25°C = (1.93 ± 0.43) × 10-6 S cm-1, the electronic conductivity was found to be (3.11 ± 0.14) × 10-10 S cm-1 for the composition 0.50Ag2O · 0.30TeO2 · 0.20P2O5. X-ray photoelectron spectroscopy studies of these glasses reveal information about the structural modifications leading to the creation of bridging oxygens and non-bridging oxygens. The detailed analysis of the Te 3d XPS spectrum of the binary and ternary systems shows the existence of different Te-based structural units like TeO4, TeO3 -, TeO2- 3 and Ag-Te bond. The results from the ternary system suggest the unique role played by P2O5 in the conversion of TeO4 units leading to the creation of Ag-Te bond and TeO2- 3 units.