Ion transport in silver–lead–borate glass and evidence of ion association

Abstract

Silver-ion transport in a 60AgI–(30 – x)Ag2O–xPbO–10B2O3 glass system is established using various experimental techniques viz. X-ray diffraction, differential scanning calorimetry, Wagner's polarization method, the E.M.F. method, complex impedance spectroscopy, transient ionic-current measurement, and optical microscopy. The glass formation is limited to x ≤ 6 mol%. The addition of PbO modifies the conductivity as a result of the increase in the ionic mobility and the decrease in the charge carrier concentration due to the formation of more nonbridging oxygen-containing functional groups. From the study of the temperature dependence of the electrical conductivity and the ionic mobility, a decrease in the charge carrier concentration is also observed with increasing temperature. To explaining this, two possible types of ion-association mechanisms are proposed viz. (i) self-association and (ii) network association.