Programmable Colloidal Approach to Hierarchical Structures of Methylammonium Lead Bromide Perovskite Nanocrystals with Bright Photoluminescent Properties

Systematic tailoring of nanocrystal architecture could provide unprecedented control over their electronic, photophysical, and charge transport properties for a variety of applications. However, at present, manipulation of the shape of perovskite nanocrystals is done mostly by trial-and-error-based experimental approaches. Here, we report systematic colloidal synthetic strategies to prepare methylammonium lead bromide quantum platelets and quantum cubes. In order to control the nucleation and growth processes of these nanocrystals, we appropriately manipulate the solvent system, surface ligand chemistry, and reaction temperature causing syntheses into anisotropic shapes. We demonstrate that both the presence of chlorinated solvent and a long chain aliphatic amine in the reaction mixture are crucial for the formation of ultrathin quantum platelets (∼2.5 nm in thickness), which is driven by mesoscale-assisted growth of spherical seed nanocrystals (∼1.6 nm in diameter) through attachment of monomers onto sel...