Publication date: 2022

DOI: 10.32523/ejpfm.2022060107

Superionic semiconductor chalcogenides with mixed electronic-ionic conductivity have very low lattice thermal conductivity and are excellent thermoelectrics. Doping with other elements is one of the methods for optimizing the useful properties of a material. In this work, nanosized polycrystalline alloys of nonstoichiometric Cu1.85S copper sulfide with a low content of potassium are studied. The paper presents the results of X-ray phase analysis, differential thermal analysis (DTA) and electron microscopy of differential thermal analysis of KxCu1.85S alloys. The resulting alloys are a mixture of phases, in which the main share is djurleite - non-stoichiometric copper sulfide of the composition Cu1.97÷1.93S, in addition, depending on the composition of the alloy, there are impurities of monoclinic and hexagonal chalcocite Cu2S, roxbyite Cu1.85S, anilite Cu1.75S, traces of metallic copper. All alloys contain inclusions of Cu2O copper oxide. DTA detected a superionic phase transition from an ordered low-symmetry djurleite phase to a disordered superionic hexagonal phase of copper sulfide at about 373-383 K. In addition, DTA revealed two thermal effects at about 433 K and 460 K, which are absent in binary copper sulfide. The reason for the effects may be the redistribution of impurity potassium ions in the copper sulfide lattice © 2022. Eurasian Journal of Physics and Functional Materials.All Rights Reserved.

Тип: Article