IV-VI/I-V-VI${}_2$ thermoelectrics. Recent progress and perspectives

Thermoelectric energy conversion technology is considered as one of the most promising solutions for recovering waste heat generated by fossil fuel combustion. As typical types of thermoelectric materials in the middle and high-temperature range (500-900 K), binary IV-VI (IV = Ge, Sn, Pb; VI = Se, Te) compounds are extensively studied. Lately, the obtained high-performance thermoelectric solid solutions between IV-VI and I-V-VI${}_2$ (I = Li, Na, K, Ag, Cu; V = Sb, Bi; VI = S, Se, Te) compounds have brought those complex chalcogenides back to the central point of thermoelectric community due to the emerging rich physical phenomena. Profiting from this effective approach, unveiling the underlying mechanism and understanding of alloying effect on the transport properties of these solid solutions becomes particularly significant. This review presents the latest progress in designing high-performance IV-VI/I-V-VI${}_2$ solid solutions and the underlining physical mechanisms, in which detailed discussion about the role of I-V-VI${}_2$ compounds play in optimizing individual properties of IV-VI materials is made. This comprehensive review highlights the multiple effects of I-V-VI${}_2$ alloying on thermoelectric properties of IV-VI compounds and will drive the related research interests aiming at developing new-generation thermoelectric compounds in this family. (© 2024 Wiley‐VCH GmbH)