Thermal, structural, and conductivity properties of As14Sb26S(60−x)–(AgI)x chalcogenide glasses

Abstract

The present work describes the preparation of a new series of chalcogenide glasses in an As14Sb26S(60−x) (AgI)x system intending to explore its thermal, structural, optical, mechanical, and electrical properties. The differential scanning calorimetry results of the studied glasses show the sharp decrease in glass transition temperature (Tg) with the successive incremental inclusion of AgI in the composition, implying the structural changes in the glass network. A thorough Raman analysis corroborates the occurrence of changes in the glass network due to the formation of AsI3 units and Ag–S–As bonds with increasing AgI content. Also, structural changes can be reflected with the change in the optical bandgap (Eg) that was calculated using Tauc equations where it was found that Eg is in harmony with the observed structural variations of glasses. The studied glasses possess a transmittance window (∼0.68–12 μm) with transmittance above 60% in the mid-infrared region. These structural changes are closely related to the significant enhancement of conductivity of the present glasses from 10−8 to 10−6 S/cm at 373 K with a decrease in activation energies. Impedance spectra for the glass with highest AgI revealed the presence of two different relaxation processes. AC conductivity data followed an Arrhenius behavior as well as Jonscher’s power law. The present work provides insights into glass network modifications due to silver iodide inclusion and its role in the enhancement of conductivity.