Intrinsic Formamidinium Tin Iodide Nanocrystals by Suppressing the Sn(IV) Impurities

Dmitry N. Dirin*, Anna Vivani, Marios Zacharias, Taras V. Sekh, Ihor Cherniukh, Sergii Yakunin, Federica Bertolotti, Marcel Aebli, Richard D. Schaller, Alexander Wieczorek, Sebastian Siol, Claudia Cancellieri, Lars P.H. Jeurgens, Norberto Masciocchi, Antonietta Guagliardi, Laurent Pedesseau, Jacky Even, Maksym V. Kovalenko, Maryna I. Bodnarchuk

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


The long search for nontoxic alternatives to lead halide perovskites (LHPs) has shown that some compelling properties of LHPs, such as low effective masses of carriers, can only be attained in their closest Sn(II) and Ge(II) analogues, despite their tendency toward oxidation. Judicious choice of chemistry allowed formamidinium tin iodide (FASnI3) to reach a power conversion efficiency of 14.81% in photovoltaic devices. This progress motivated us to develop a synthesis of colloidal FASnI3 NCs with a concentration of Sn(IV) reduced to an insignificant level and to probe their intrinsic structural and optical properties. Intrinsic FASnI3 NCs exhibit unusually low absorption coefficients of 4 × 103 cm-1 at the first excitonic transition, a 190 meV increase of the band gap as compared to the bulk material, and a lack of excitonic resonances. These features are attributed to a highly disordered lattice, distinct from the bulk FASnI3 as supported by structural characterizations and first-principles calculations.

Original languageEnglish (US)
Pages (from-to)1914-1923
Number of pages10
JournalNano letters
Issue number5
StatePublished - Mar 8 2023


  • halide perovskite
  • lead-free
  • nanocrystals

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanical Engineering
  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)


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