Synthesizing Metal Thiolates As Soluble Precursors for Multinary Sulfides

Multinary metal sulfides are an interesting class of materials many different properties. Of particular interest are the semiconducting metal sulfides which can be used for solar energy generation. While much research has been devoted to solution processing these materials when they contain late- and post-transition metals, but very little has been done for materials that contain alkaline earth metals. Solution-based approaches are desired because they can offer low energy, low cost, and scalable manufacturing processes. Therefore, this project focuses on creating a procedural basis for synthesizing multinary sulfides that contain alkaline earth metals (binary, tertiary and quaternary) with soluble metal thiolates precursors. The main procedure begins with a metal precursor that is reacted with a thiol in order to introduce a sulfur source. An appropriate solvent is selected, such as an amine, in order to form a precursor solution. Various metal precursors, thiols, and solvents are tested, ranging in polarity and size. If a metal thiolate solution is formed, then decomposition into the desired metal sulfide is performed by drop coating and heating the solution into films and then analyzing with XRD. Through this procedure, various multinary sulfides have been synthesized including Cu2BaSnS4 and the chalcogenide perovskite BaZrS3. This pathway opens up the possibility for widespread usage of multinary sulfides that contain alkaline earth metals in the fabrication of solar cells that can further sustainable energy goals.