Synergistic Experimental and Computational Research on New Multinary Chalcogenides with Earth Abundant Constituents

Multinary metal chalcogenides are known to form in a variety of structure types and exhibit varying properties depending on composition, crystal structure, chemical bonding, and processing conditions. Nevertheless, providing new avenues for discovery allows for pathways towards the design of new materials, and processing techniques, with targeted properties for specific applications of interest. One such approach is by cation substitution methods, where one can “build” a variety of materials with different chemical formulas while maintaining the valence electron count. Moreover, knowledge of the thermal properties is essential for any application of interest, particularly for thermoelectric, thermophotovoltaic, thermos-acoustic and thermal barrier materials, where low thermal conductivity is obtained when specific features, such as weak bonding, coordination preferences, lone pair electrons, large number of atoms per unit cell, nanoscale effects and strong anharmonicity, are realized. Motivated by these considerations and our continued interest in the effect of complex structure and disorder on the thermal properties of multinary chalcogenides, we investigated the thermal and electronic properties of several new chalcogenides employing cationic substitution. We expand on the techniques we’ve previously employed in investigating Kesterites and Stannites, and will present our most recent work on the structure-property relationships of materials with Adamantine, Sphalerite and Aikinite crystal structures. An intrinsically low thermal conductivity is typical in these materials, and a result of lattice anharmonicity as well as the particular bonding and, in some cases, defects these materials possess. Our research provides a better understanding of the fundamental properties of these materials, with an eye towards determining their suitability for use in thermoelectric applications.