Quantitative Scales for Haliphilicity of Metals: Tailoring the Halide Affinity of Alkaline Earth Metals to Synthesize Chalcogenide Perovskite BaMS₃ (M = Zr, and Hf) and Cu₂BaSnS₄ Compounds

Chalcogenide semiconductors, such as BaMS3 (M = Zr and Hf) and Cu2BaSnS4, have attracted growing interest due to the constituent elements’ abundance and reported promising properties. However, the synthesis of these alkaline earth-containing chalcogenides from commonly available metal halides has generally been unsuccessful and has traditionally relied on expensive organometallic precursors or vacuum processing techniques, which hinder widespread research on these materials. In this study, we conducted thermodynamic calculations and developed chloriphilicity and iodiphilicity scales for various metals, leveraging their relative affinities for chlorine and iodine, respectively, compared to their corresponding metal sulfides. Utilizing these scales, we introduced a K2S–H2S system to address the affinity of alkaline earth metals for chlorine and iodine. This approach enables the synthesis of these intriguing chalcogenide materials through solution-based methods using metal chloride and metal iodide precursors. This system demonstrates remarkable efficacy for both sulfide and selenide semiconductors.