EXPERIMENTAL STUDIES AND SPACE-CHARGE MECHANISM FOR THE CONDUCTIVITY MOBILITY ENHANCEMENT DUE TO SNO2 DISPERSION IN AG+ ION CONDUCTING BORATE GLASS

The enhancement in ionic conductivity of a Ag+ ion conducting borate glass of molar % composition 55.5 Agl-22.25 Ag2O-22.25 B2O3 is reported with the dispersion of SnO2. X-ray diffraction (XRD), i.r. and optical microscopy reveals that the SnO2 addition yields a dispersed phase material and not a new glass. The material is essentially a Ag+ ion conducting (Agl + Ag2O + B2O3) glass in which SnO2 is dispersed, The direct measurement of mobility of the mobile ions reveals that the enhancement in conductivity is controlled by the enhancement in mobility. A space charge model based on the mechanism of adsorption-desorption of mobile ions near/at the interface in the space charge region creating a certain type of mobile ion concentration gradient is introduced to explain the results.