Growth and Self-Assembly of CsPbBr<sub>3</sub> Nanocrystals in the TOPO/PbBr<sub>2</sub> Synthesis as Seen with X-ray Scattering.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 36607192.
- Also identified by DOI 10.1021/acs.nanolett.2c04532 and PMC identifier 9881167.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Despite broad interest in colloidal lead halide perovskite nanocrystals (LHP NCs), their intrinsic fast growth has prevented controlled synthesis of small, monodisperse crystals and insights into the reaction mechanism. Recently, a much slower synthesis of LHP NCs with extreme size control has been reported, based on diluted TOPO/PbBr<sub>2</sub> precursors and a diisooctylphosphinate capping ligand. We report new insights into the nucleation, growth, and self-assembly in this reaction, obtained by <i>in situ</i> synchrotron-based small-angle X-ray scattering and optical absorption spectroscopy. We show that dispersed 3 nm Cs[PbBr<sub>3</sub>] agglomerates are the key intermediate species: first, they slowly nucleate into crystals, and then they release Cs[PbBr<sub>3</sub>] monomers for further growth of the crystals. We show the merits of a low Cs[PbBr<sub>3</sub>] monomer concentration for the reaction based on oleate ligands. We also examine the spontaneous superlattice formation mechanism occurring when the growing nanocrystals in the solvent reach a critical size of 11.6 nm.