Formation mechanisms and electrical properties of perovskite mesocrystals

Mesocrystals are oriented polycrystals with superstructures consisting of crystallographically ordered nanocrystals. They usually show the electron diffraction behaviour of a single crystal owing to the high order of the nanoscale building units. Mesocrystals have potential applications in many processes such as catalysis, sensing, energy storage and conversion. Perovskite mesocrystals are a novel class of mesocrystalline dielectric nanomaterials that exhibit synergistic properties and anomalous electrical properties; so they have been extensively studied in various fields. This review investigates the chemical formation processes, formation mechanisms and mechanisms that affect performance of perovskite mesocrystals. Moreover, the formation mechanisms of perovskite mesocrystals, namely topochemical mesocrystal conversion mechanism is discussed. Understanding and application of these mechanisms are important for the design and preparation of advanced structural and functional materials. Most importantly, mesocrystal-derived functional materials can be designed by combining orientation, strain, and domain engineering. The potential applications of perovskite mesocrystals as structural and functional materials in piezoelectric, ferroelectric, dielectric, and catalytic devices as well as perovskite solar cells are discussed. This investigation not only develops the chemistry of mesocrystals and proposes new routes for the design of oriented film and ceramic materials, but also provides theoretical support for future applications of perovskite mesocrystals in material science.