Benzoyl Versus Phenacyl Bromide: The Strategic Differences in Halide Perovskite Nanocrystals Design

Facet engineering in nanocrystals is typically controlled by the surface atoms of the crystal and the interaction of interface binding ligands. This has been extensively studied for covalent chalcogenide nanocrystals, but little progress has been made for ionic halide perovskite nanocrystals. Stabilizing the different surface facets, mostly, determines the nature of the polyhedral shapes and also helps in understanding the formation of their anisotropic structures. Recent progresses of different polyhedral halide perovskite nanocrystals suggest that their formations are mostly reagent specific. Two halide reagents, benzoyl bromide and phenacyl bromide, which are only different in one -CH2- group, showed drastic difference in the shapes of resulting CsPbBr3 nanocrystals. While former resulted in the cube shape, the later triggered the formation of dodecahedron-shaped nanocrystals. Keeping this in mind, the chemical activities of these reagents for the shape evolution of binary and ternary metal halides and their conversion to halide perovskites with B-site ions introduction are investigated in detail and reported in this perspective. In addition, the cross exchanges in these two reagents and other possible pathways are also proposed for possible dimension tunable halide perovskite nanocrystals.