Self‐assembly Behavior of Metal Halide Perovskite Nanocrystals

Comprehensive Summary The self‐assembled metal halide perovskite (MHP) nanocrystal superlattices have attracted many researchers due to their exceptional optical and electrical properties. The bottom‐up self‐assembly can be facile to generate ideal and periodic structures. The superlattices’ stability can be improved and the photoluminescence lifetime can be extended by an order of magnitude. However, due to lack of a comprehensive and systematic understanding of the internal interactions on self‐assembled processes now, superlattices cannot be obtained controllably and play full use of their advantages. Therefore, gaining a deep insight of interaction forces about self‐assemblies is the premise of designing and controlling the degree of self‐assembly so as to prepare ideal materials. In this review, the definitions and functions of driving forces including van der Waals forces, electrostatic interactions and hydrogen bonds are discussed. Subsequently, we aim to explore the dominant factors affecting the driving forces, which can make a difference in the process of MHP self‐assembly. Based on current researches, we emphasize on three aspects−the core of nanocrystals, surface ligands and solvents−to clarify their critical roles in controlling the driving forces. Finally, the outlooks and perspectives of how to facilitate the MHP self‐assembly and their application on blue light emitting diodes are discussed. Compared with top‐down strategies, the bottom‐up self‐assembly offers a facile and time‐saving technique to create micrometer‐scale to macroscale structures. We emphasize on three aspects−the core of nanocrystals, surface ligands and solvents−to clarify their critical roles in controlling the driving forces during the process of self‐assembled metal halide perovskite due to lack of comprehension on them at present.