Ligands Mediate Anion Exchange between Colloidal Lead-Halide Perovskite Nanocrystals

Einav Scharf, Franziska Krieg, Orian Elimelech, Meirav Oded, Adar Levi, Dmitry N. Dirin, Maksym V. Kovalenko, Uri Banin*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

31 Scopus citations

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.

Original languageAmerican English
Pages (from-to)4340-4346
Number of pages7
JournalNano Letters
Volume22
Issue number11
DOIs
StatePublished - 8 Jun 2022

Bibliographical note

Publisher Copyright:
© 2022 American Chemical Society.

Keywords

  • anion exchange
  • kinetics
  • perovskite nanocrystals
  • surface ligands

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