Colloidal Synthesis of CH₃ NH₃ PbBr₃ Nanoplatelets with Polarized Emission through Self-Organization

We report a combined experimental and theoretical study of the synthesis of CH₃ NH₃ PbBr₃ nanoplatelets through self-organization. Shape transformation from spherical nanodots to square or rectangular nanoplatelets can be achieved by keeping the preformed colloidal nanocrystals at a high concentration (3.5 mg mL^-1 ) for 3 days, or combining the synthesis of nanodots with self-organization. The average thickness of the resulting CH₃ NH₃ PbBr₃ nanoplatelets is similar to the size of the original nanoparticles, and we also noticed several nanoplatelets with circular or square holes, suggesting that the shape transformation experienced a self-organization process through dipole-dipole interactions along with a realignment of dipolar vectors. Additionally, the CH₃ NH₃ PbBr₃ nanoplatelets exhibit excellent polarized emissions for stretched CH₃ NH₃ PbBr₃ nanoplatelets embedded in a polymer composite film, showing advantageous photoluminescence properties for display backlights.