Heterolayered Anion-Mixed Salt-Inclusion Structures

Mixed-anion materials are on the frontier of modern research since they present an additional tool to control electronic and structural properties as a function of the anion. In fact, those materials have demonstrated outstanding potential for applications that include batteries, superconductivity, thermoelectrics, electronics, and magnetism. Heterolayered anion-mixed (HAM) structures consist of two or more alternating sheets, usually built from different anions, e.g., combinations of halide-oxide, chalcogenide-oxide, halide-chalcogenide slabs, and etc. The functional anion separation present in HAM materials can be boosted even further if the HAM structure contains both a covalent and an ionic building block, i.e., a salt inclusion, then it becomes heterolayered anion-mixed salt-inclusion (HAMSI) material. Up to date, nearly 40 HAMSI are known that represent less than 10 crystal structure families. Understanding the formation of those materials and expanding their number and functionality is of interest to material science and the solid-state community. Specifically, the first half of the talk will focus on the synthesis and classification of known chalcogenide containing HAMSI phases based on their topology, dimensionality, and crystal chemistry. This is the first step to understanding how to design HAMSI with enhanced properties. In the second half, a new family of HAMSI [Na₂Cl]Ga<i>Q</i>₂ (<i>Q</i> = S and Se) containing [Na₂Cl]⁺ salt-inclusion layers alternating with [Ga<i>Q</i>₂]^– sheets obtained through flux crystal growth will be discussed. Novel functionality of heterolayered materials, i. e., radioactive species sorption, will be uncovered as well as we will demonstrate how to use anion-mixed composition advantage to tune the photoluminescence profile of Mn-dopped [Na₂Cl]GaS₂ single crystals.<br/>Reference: Berseneva, A. A.; Klepov, V. V.; Tisdale, H. B.; zur Loye, H.-C. Flux-assisted Polytypism in the [Na₂Cl]Ga<i>Q</i>₂ Heterolayered Salt-Inclusion Chalcogenide Family. <i>CrystEngComm.</i> <b>2023</b>, <i>25</i> (15), 2307-2312.