“…Unlike covalent chalcogenide nanocrystals, the chemistry of crystal modulations and surface engineering also could not be largely understood. Enormous efforts have been put forward in tuning ligands, designing new precursors, changing the reaction medium, and also varying different reaction parameters to slow down the rate of their formation, which remained a key parameter for facet dependent secondary growth and the shape modulation. ,,− In some cases, successes have also been achieved in the formation of different polyhedral nanocrystals, connected nanocrystals, nanorods/nanowires, nanoplatelets, and other anisotropic nanostructures with different anisotropy directions. − However, to rationalize this facet or shape control, there is no logical pathway or fundamental principle yet established which would provide guidelines to follow their formation.
From the chronological development of these nanocrystals, it is revealed that the halide source remained as one of the major key parameters for controlling the surface facets of these nanocrystals. ,− Among these, benzoyl halides and phenacyl halides, which have broadly similar structures, but differing in only one −CH 2 – group, made a significant impact in designing the nanocrystals. , One resulted in the cube shape, and other turned halide perovskite nanocrystals to a dodecahedron shape having different groups of surface facets and symmetry. This indeed created the benchmark and provided hopes for the revolutionary pathway in nanocrystals engineering in halide perovskite nanocrystals.…”