Cation Engineering in Two-Dimensional Ruddlesden-Popper Lead Iodide Perovskites with Mixed Large A-Site Cations in the Cages

Yongping Fu, Xinyi Jiang, Xiaotong Li, Boubacar Traore, Ioannis Spanopoulos, Claudine Katan, Jacky Even, Mercouri G. Kanatzidis, Elad Harel

Research output: Contribution to journalArticle


The Goldschmidt tolerance factor in halide perovskites limits the number of cations that can enter their cages without destabilizing their overall structure. Here, we have explored the limits of this geometric factor and found that the ethylammonium (EA) cations which lie outside the tolerance factor range can still enter the cages of the 2D halide perovskites by stretching them. The new perovskites allow us to study how these large cations occupying the perovskite cages affect the structural, optical, and electronic properties. We report a series of cation engineered 2D Ruddlesden-Popper lead iodide perovskites (BA)2(EAxMA1-x)2Pb3I10 (x = 0-1, BA is n-butylammonium, MA is methylammonium) by the incorporation of a large EA cation in the cage. An analysis of the single-crystal structures reveals that the incorporation of EA in the cage significantly stretches Pb-I bonds, expands the cage, and induces a larger octahedral distortion in the inorganic framework. Spectroscopic and theoretical studies show that such structural deformation leads to a blue-shifted bandgap, sub-bandgap trap states with wider energetic distribution, and stronger photoluminescence quenching. These results enrich the family of 2D perovskites and provide new insights for understanding the structure-property relationship in perovskite materials.

Original languageEnglish
Pages (from-to)4008-4021
Number of pages14
JournalJournal of the American Chemical Society
Issue number8
Publication statusPublished - Feb 26 2020


ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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