Diffusion Controlled Growth of CsPbBr₃ Nanocrystals Using a Liquid-Liquid Interface

Lead halide perovskite nanocrystals have emerged as promising semiconductor materials due to their size-tuneable emissive properties, solution processability, and high quantum yields. The controlled synthesis of these nanocrystals is an extensive area of research and allows one to obtain precise sizes and optical properties. However, the ionic nature of these nanocrystals causes instantaneous formation, disfavouring the monitoring of continuous crystal growth and, consequently, its regulation. It is important to reduce the crystal growth kinetics to monitor the growth kinetics. To achieve this; a diffusion-controlled growth approach has been utilized in this work. A confined liquid-liquid (L/L) interface is used to grow CsPbBr₃ nanocrystals, and the slow diffusion of ions into the interface allows continuous growth to be monitored using in-situ photoluminescence (PL). Altering the precursor ions' concentration reduces the nanocrystal growth rate, supporting the diffusion-controlled growth kinetics. Moreover, we also demonstrate the regulation of the growth kinetics by tuning the diffusion field and the size of the L/L interface.Through this study, insights on the growth kinetics can be obtained for CsPbBr₃ without the use of any tight binding ligands, therefore providing alternate routes to modify the crystal growth.