Halide Perovskite Cluster Precursors: A Paradigm for Obtaining Structure- and Color-Tunable Light-Emitting Nanocrystals

The compositions of precursors during the syntheses of CsPbX3 nanocrystals typically determine the resulting crystal phase and stability. Different precursors providing single or multiple constituent ions have already been developed for tuning the reaction pathways for architecting different sizes and shapes of such nanocrystals. Among these, the CsPbBr3 clusters, composed of Cs, Pb, and Br, as well as limited ligands, employed as single-source precursors, provide an ideal pathway for obtaining a wide window of size/shape-tunable CsPbBr3 nanocrystals. Recent reports also revealed that this pathway can lead to the epitaxial growth of non-perovskite nanostructures on perovskite nanocrystals. Further, the limited ligands here helped in shape modulation by opening different facets and also triggering facet directed connections of the nanocrystals. Keeping those in mind, the importance of these unique cluster precursors for the development of halide perovskite nanocrystals and their heterostructures is discussed, and possibilities for their utilization in different unexplored areas of research are proposed in this Perspective.