Ames Laboratory, Chemistry
Journal or Book Title
Chemistry of Materials
Soft chemistry methods offer the possibility of synthesizing metastable and kinetic products that are unobtainable through thermodynamically-controlled, high-temperature reactions. A recent solution-phase exploration of Li-Zn-Sb phase space revealed a previously unknown cubic half-Heusler MgAgAs-type LiZnSb polytype. Interestingly, this new cubic phase was calculated to be the most thermodynamically stable, despite prior literature reporting only two other ternary phases (the hexagonal half-Heusler LiGaGe-type LiZnSb, and the full-Heusler Li2ZnSb). This surprising discovery, coupled with the intriguing optoelectronic and transport properties of many antimony containing Zintl phases, required a thorough exploration of syn-thetic parameters. Here, we systematically study the effects that different precursor concentrations, injection order, nucleation and growth temperatures, and reaction time have on the solution-phase synthesis of these materials. By doing so, we identify conditions that selectively yield several unique ternary (c-LiZnSb vs. h*-LiZnSb), binary (ZnSb vs. Zn8Sb7), and metallic (Zn, Sb) products. Further, we find one of the ternary phases adopts a variant of the previously observed hexagonal LiZnSb struc-ture. Our results demonstrate the utility of low temperature solution phase—soft synthesis—methods in accessing and mining a rich phase space. We anticipate that this work will motivate further exploration of multinary I-II-V compounds, as well as encourage similarly thorough investigations of related Zintl systems by solution phase methods.
American Chemical Society
White, Miles A.; Baumler, Katelyn J.; Chen, Yunhua; Venkatesh, Amrit; Medina-Gonzalez, Alan M.; Rossini, Aaron; Zaikina, Julia; Chan, Emory; and Vela, Javier, "Expanding the I-II-V Phase Space: Soft Synthesis of Polytypic Ternary and Binary Zinc Antimonides" (2018). Chemistry Publications. 1051.