Scalable synthesis of efficiently luminescent and color-tunable CsPbX3 (X=Cl, Br, I) nanocrystals by regulating the reaction parameters

All-inorganic CsPbX 3 (X=Cl, Br, I) perovskite nanocrystals (NCs) exhibit attractive optoelectronic properties for lighting and displays application but suffer from the lack of profound insights into their reaction kinetics. Herein, a modified ligand-assisted reprecipitation (LARP) method was developed to synthesize high-quality CsPbBr 3 NCs by utilizing oleic acid (OA) and n-octylamine (OTAm) as surface ligands, and the effect of Cs/Pb ratio, precursors and ligands concentration on the structure, morphology and fluorescence properties was systematically investigated. The monodisperse CsPbBr 3 NCs with cubic shape and average particle size of 13.7 nm are obtained by optimizing the reaction parameters. Appropriately increasing the Cs/Pb ratio and precursors concentration to 0.5 and 1.0 mM are favorable for forming a more complete crystal structure with lower defect states density, which can significantly enhance the PL intensity. Notably, the surface defect states of CsPbBr 3 NCs are effectively passivated by the coordinated OA and OTAm ligands, and the maximum photoluminescence quantum yield (PLQY) can reach to 85.2%. Importantly, the effective synthesis of high-quality CsPbBr 3 NCs can be amplified up to 50 times of reaction volume after finely optimizing the reaction parameters. Based on a facile anion exchange process, the CsPbX 3 NCs with variable halogen composition exhibit tunable emission of 443.3∼649.1 nm and a wide color gamut of 117% NTSC standard. This work provides profound sights on the reaction kinetics of perovskite NCs, and further promotes its practical application in optoelectronic field.