Understanding the ligand-assisted reprecipitation of CsPbBr3 nanocrystals via high-throughput robotic synthesis approach

Abstract

•High-throughput automated experimental workflow for LARP-PNC synthesis is employed •Effects of chemical and processing parameters on PNC functionalities are explored •SHAP, a machine learning method, assesses the impact of synthesis parameters •Ligand diffusion during reaction determines the functionalities of PNCs Inorganic cesium lead bromide (CsPbBr3) perovskite nanocrystals (PNCs) have shown promise in optoelectronic applications. A simpler method of synthesizing high-quality PNCs is the ligand-assisted reprecipitation (LARP) method, but it is susceptible to instability. This study used a high-throughput automated experimental platform to explore the growth behaviors and colloidal stability of LARP-synthesized PNCs. The influence of ligands on particle growth and functionalities was systematically explored using two distinctive acid-base pairs. The study found that short-chain ligands cannot make functional PNCs with the desired sizes and shapes, whereas long-chain ligands provide homogeneous and stable PNCs. The study also found that excessive amines or polar antisolvents can cause PNCs to transform into a Cs-rich non-perovskite structure with poorer emission functionalities and larger size distributions. The diffusion of ligands in a reaction system is crucial in determining the structures and functionalities of the PNCs. This study provides detailed guidance on synthesis routes for desired PNCs. Inorganic cesium lead bromide (CsPbBr3) perovskite nanocrystals (PNCs) have shown promise in optoelectronic applications. A simpler method of synthesizing high-quality PNCs is the ligand-assisted reprecipitation (LARP) method, but it is susceptible to instability. This study used a high-throughput automated experimental platform to explore the growth behaviors and colloidal stability of LARP-synthesized PNCs. The influence of ligands on particle growth and functionalities was systematically explored using two distinctive acid-base pairs. The study found that short-chain ligands cannot make functional PNCs with the desired sizes and shapes, whereas long-chain ligands provide homogeneous and stable PNCs. The study also found that excessive amines or polar antisolvents can cause PNCs to transform into a Cs-rich non-perovskite structure with poorer emission functionalities and larger size distributions. The diffusion of ligands in a reaction system is crucial in determining the structures and functionalities of the PNCs. This study provides detailed guidance on synthesis routes for desired PNCs.