Influence of glassy backbone on the photoformation and properties of solid electrolytes Ag: As-S-Ge

Abstract

The effect of the glassy backbone on the process of fabrication and some properties of solid electrolytes obtained via photodissolution (PD) of Ag into chalcogenide glasses (ChG) of the system As-S-Ge have been studied with respect to XRD and far IR spectroscopy analyses. The compositional tie – line (GeS4)x (AsS3)1-x has been chosen to realize the monotonic transition of the structural units of glassy backbone from trigonal to tetragonal configuration. It is shown that the process of solid electrolyte formation occurs in three steps, but the last two steps, as well as the electrical properties of the finally fabricated electrolyte, are strongly influenced by chemical composition and microstructure of the used ChG backbone. The rate of solid electrolyte formation exhibit a maximum around of glassy backbone composition (GeS4)0.33(AsS3)0.67 but the electrical resistivity of fabricated solid electrolytes reaches a minimum at this composition. Based on IR transmission spectra analyses, it is assumed that these peculiarities are due to glass homogenization, which results from building in this alloyed composition of an amalgamation of tetrahedral and trigonal structural units connected in a random network, without clustering. Such homogenization promotes the transport of both electrons and ions involved in photoreaction because of lack of phase boundaries and additional defects.