Low-Temperature Synthesis and Thermodynamic Properties of the AgGaGeS4 Compound for Potential Applications in Optoelectronics and Gas Sensors

Abstract

In this study, the low-temperature synthesis and thermodynamic properties of the AgGaGeS4 compound were analyzed in detail for potential applications in optoelectronics and gas sensors. The existence of two four-phase regions Ge–GeS–Ga2S3–AgGaGeS4 and GeS–GeS2–Ga2S3–AgGaGeS4 in the Ge–GeS2– Ga2S3–AgGaS2 part of the Ag–Ga–Ge–S system, which are in equilibrium below (540 ± 5) K, has been confirmed through the modified electromotive force (EMF) method. The spatial position of the four-phase regions relative to the silver point was employed to ascertain the overall potential-forming reactions of the AgGaGeS4 synthesis from mixtures of silver, germanium, and compounds (Ga2S3, GeS, GeS2, AgGaS2) in the positive electrodes of electrochemical cells. Based on the results obtained, the temperature dependences of the EMF of electrochemical cells were used to determine the values of standard thermodynamic functions (Gibbs energy, enthalpy, and entropy) of the AgGaGeS4 compound.