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Updated: Sep 22, 2025

Facile Synthesis of Colloidal Lead Halide Perovskite Nanoplatelets via Ligand-Assisted Reprecipitation
Published on: October 1, 2019
Ligands Mediate Anion Exchange between Colloidal Lead-Halide Perovskite Nanocrystals
Einav Scharf1, Franziska Krieg2,3, Orian Elimelech1
1The Institute of Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Abstract:
The soft lattice of lead-halide perovskite nanocrystals (NCs) allows tuning their optoelectronic characteristics via anion exchange by introducing halide salts to a solution of perovskite NCs. Similarly, cross-anion exchange can occur upon mixing NCs of different perovskite halides. This process, though, is detrimental for applications requiring perovskite NCs with different halides in close proximity. We study the effects of various stabilizing surface ligands on the kinetics of the cross-anion exchange reaction, comparing zwitterionic and ionic ligands. The kinetic analysis, inspired by the "cage effect" for solution reactions, showcases a mechanism where the surface capping ligands act as anion carriers that diffuse to the NC surface, forming an encounter pair enclosed by the surrounding ligands that initiates the anion exchange process. The zwitterionic ligands considerably slow down the cross-anion exchange process, and while they do not fully inhibit it, they confer improved stability alongside enhanced solubility relevant for various applications.
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