The Role Silver Nanoparticles Plays in Silver-Based Double-Perovskite Nanocrystals

Shai Levy, Sasha Khalfin, Nicholas G. Pavlopoulos, Yaron Kauffmann, Galit Atiya, Saar Shaek, Shaked Dror, Reut Shechter, Yehonadav Bekenstein

Research output: Contribution to journalArticlepeer-review

Abstract

Lead-free double perovskites are studied as an optional replacement to lead halide perovskites in optoelectronic applications. Recently, double-perovskite materials in which two divalent lead cations are replaced with an Ag+ and a trivalent cation have been demonstrated. The presence of a reactive silver cation and observations of metallic silver nanodecorations raised concerns regarding the stability and applicability of these materials. To better understand the nucleation and crystal growth of lead-free double perovskites, we explore the origin and role that metallic silver nanoparticles (NPs) play in the Ag-based Pb-free double-perovskite nanocrystal (NC) systems such as Cs2AgInCl6, Cs2AgSbCl6, Cs2AgBiCl6, and Cs2AgBiBr6. With major focus on Cs2AgInCl6 NCs, we show evidence supporting growth of the NCs through heterogeneous nucleation on preexisting metallic silver seeds. The silver seeds nucleate prior to injection of halide through reduction of the Ag+ ion by the aminic ligand. The presence of preexisting silver NPs is supported by a localized surface plasmon resonance (LSPR). The injection of halide precursor into the reaction mixture step initiates a fast nucleation and growth of the perovskite NC on the silver seed. The change in the dielectric medium at the interface of the silver NP results in a quantifiable red shift of the LSPR peak. In addition, we demonstrate charge transfer from the perovskite to the silver NP through photoinduced electrochemical Ostwald ripening of the silver NPs via UV irradiation. The ripened perovskite-metal hybrid nanocrystal exhibits modified optical properties in the form of quenched emission and enhanced plasmonic absorption. Future development of Ag-based double-perovskite NC applications depends on the ability to control Ag+ reduction at all synthetic stages. This understanding is critical for delivering stability and functionality for silver-based lead-free perovskite nanocrystals.

Original languageEnglish
Pages (from-to)2370-2377
Number of pages8
JournalChemistry of Materials
Volume33
Issue number7
DOIs
StatePublished - 13 Apr 2021

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • General Chemical Engineering
  • Materials Chemistry

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