Toward the green synthesis of CsPbBr3 perovskite nanocrystals using ethanol as an antisolvent and cyclodextrin as a ligand

Abstract

Metal halide perovskite nanocrystals (PNCs) exhibiting excellent optoelectronic properties have been commonly synthesized by the ligand-assisted reprecipitation (LARP) method. However, the application of the LARP method for the large-scale production of PNCs is greatly hindered by the heavy use of the toxic antisolvent toluene and alkylamine ligand. In this study, ethanol was used as the antisolvent to synthesize CsPbBr₃ PNCs at room temperature, which was enabled by simply using cyclodextrin (α-CD) as the ligand. The proposed method could produce α-CD@CsPbBr₃ PNCs with a size of 35.0 ± 0.6 nm, a photoluminescence quantum efficiency of 86.0 ± 0.1%, and a yield of 33.4 ± 0.6% (5 batches). In addition, the obtained α-CD@CsPbBr₃ PNCs could persist for 6 months in ethanol with a loss of luminescence of less than 10%. The effective generation, high reproducibility, and long-term stability of the PNCs were contributed from the strong interaction between α-CD and CsPbBr₃ and the poor solubility of α-CD in ethanol, which resulted in a firm enclosing of CsPbBr₃ crystals within α-CD molecules. Additionally, the anion exchanges of the α-CD@PNCs were rapidly achieved in ethanol by using common salts of KI and NaCl. Using a non-toxic and low-cost antisolvent and ligand, this method is more eco-friendly and economical than ever.