Striking the balance between the capping ligands for CsPbBr₃ nanocrystal synthesis via an emulsion LARP approach

The presence of surface ligands plays a vital role in driving the growth kinetics of metal halide perovskite nanocrystals (NCs). Irrespective of the synthesis method, their influence is essential for achieving the desirable optical and morphological properties of such nanocrystals. However, there is still a lot of debate over the selection of the ligands and their functioning during the growth process of halide perovskites. Yet, most of the studies agree that the combination of oleic acid (OA) and oleylamine (OLA) plays a pivotal role in the synthesis of CsPbBr₃ NCs. In this study, the impact of OA and OLA ligands on the synthesis and properties of CsPbBr₃ NCs has been investigated, and their growth mechanism has been established. An emulsion-based ligand-assisted reprecipitation (emulsion LARP) approach was adopted for the synthesis of these NCs. The findings of this study revealed that a balanced proportion of OA and OLA is crucial for ensuring optimum passivation of surface defects and obtain sharp excitonic emission bands in the green region.