Expanding the I-II-V Phase Space: Soft Synthesis of Polytypic Ternary and Binary Zinc Antimonides

Soft chemistry methods offer the possibility of synthesizing metastable and kinetic products that cannot be obtained 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 LiGaGe-type LiZnSb and the cubic 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 synthetic 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...