Making by Grinding: Mechanochemistry Boosts the Development of Halide Perovskites and Other Multinary Metal Halides

Abstract Mechanochemical synthesis has recently emerged as a promising route for the synthesis of functional lead halide perovskites as well as other (lead‐free) metal halides. Mechanochemical synthesis presents several advantages with regards to more commonly used solution‐based processes such as an inherent lower toxicity by avoiding organic solvents and a finer control over stoichiometry of the final products. The ease of implementation, either through the use of a simple mortar and pestle or with an electrically powered ball‐mill, and low amount of side products make mechanochemical synthesis appealing for upscaling the production of halide perovskites. Due to the defect tolerance of lead halide perovskites, they are ideally suited to be prepared by this solvent‐free method. However, the implementation of these semiconductors in high‐efficiency optoelectronic devices requires the transformation of synthesized powder into smooth thin films where still some hurdles remain to be cleared.