Ligand Mediated Transformation of Cesium Lead Bromide Perovskite Nanocrystals to Lead Depleted Cs4PbBr6 Nanocrystals

• Published in: Journal of the American Chemical Society Vol. 139; no. 15; pp. 5309 - 5312
• Main Authors: Liu, Zeke, Bekenstein, Yehonadav, Ye, Xingchen, Nguyen, Son C, Swabeck, Joseph, Zhang, Dandan, Lee, Shuit-Tong, Yang, Peidong, Ma, Wanli, Alivisatos, A. Paul
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 19.04.2017; American Chemical Society (ACS)
• Subjects: INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; MATERIALS SCIENCE
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/jacs.7b01409

Lead halide perovskite nanocrystals (NCs) have emerged as attractive nanomaterials owing to their excellent optical and optoelectronic properties. Their intrinsic instability and soft nature enable a post-synthetic controlled chemical transformation. We studied a ligand mediated transformation of presynthesized CsPbBr3 NCs to a new type of lead–halide depleted perovskite derivative nanocrystal, namely Cs4PbBr6. The transformation is initiated by amine addition, and the use of alkyl-thiol ligands greatly improves the size uniformity and chemical stability of the derived NCs. The thermodynamically driven transformation is governed by a two-step dissolution–recrystallization mechanism, which is monitored optically. Our results not only shed light on a decomposition pathway of CsPbBr3 NCs but also present a method to synthesize uniform colloidal Cs4PbBr6 NCs, which may actually be a common product of perovskite NCs degradation.