The synthesis of MAPbBr₃ nanoplatelets with long-term stability and high photoluminescence quantum yield through controlling the synthetic temperature and dilution treatment

Organometal halide perovskite nanocrystals are very promising for optoelectronic applications due to their unique optical properties. However, the OHP nanocrystals generally suffer from problems such as nonuniform morphology and poor stability. This work reports the synthesis of MAPbBr₃ nanoplatelets through dilution of the irregular colloidal MAPbBr₃ nanocrystals prepared at 50 °C. The dilution followed by self-organization of the nanocrystals result in the production of uniform square nanoplatelets with long term stability up to 6 months and high photoluminescence quantum yield about 90%. Furthermore, by using bidentate coordination molecule pyrazole as co-ligand, regular 2D structural Nanocrystals with round edge and aggregation were produced. The aggregated nanoplatelets prepared at 50 °C show the same self-assembly process after dilution to form uniform square nanoplatelets.