The latest technologies require new promising compounds or improvement of the properties of already known ones that contain abundant and cheap elements. The study of phase equilibria in multicomponent systems with the participation of complex substances, determining the boundaries of the existence of their solid solution ranges is one of the stages of a systematic study of the interaction of chalcogenides. An important place belongs to the systems of the AI2S – BIVS2 – CV2S3 type, where AI – Сu, Ag; BIV – Ge, Sn; CV – As, Sb. The ternary compounds Сu(Ag)8GeS6, Ag8SnS6 та Сu(Ag)2Ge(Sn)S3, formed in these systems are promising materials for practical use as semiconductors, nonlinear optical materials, functional materials for electronic equipment, and photovoltaic cells. Materials with ion-electron conductivity based on superionic conductors Cu(Ag)7PS6, with an argyrodite structure Cu(Ag)8Ge(Sn)S6 are also of particular interest. Such materials have found use in solid-state ionics because they have significant cationic conductivity in the solid state and also possess valuable physicochemical and electrophysical properties. The formation of new compounds and solid solutions of copper- and silver-containing chalcogenides expands the range of valuable promising semiconductor materials with nonlinear optical, photoelectric, and thermoelectric properties for technology.
In recent years, systems in a metastable state have been actively studied. Due to wide transparency range, valuable optical properties, chemical resistance, chalcogenide glasses are used in IR optics, optoelectronics, telecommunications devices, laser technology, as a medium for holography, optical recording of information, etc.
Therefore, it is interesting in the scientific aspect, and in the future also in the applications, to study the trends of the component interaction, to determine the glass formation regions in the studied systems to establish the existence of new quaternary compounds, solid solutions and glassy alloys. Such studies can become a reliable scientific basis for obtaining materials with pre-set properties and predict areas of their practical application.
