Dynamic Disorder, Band Gap Widening, and Persistent Near-IR Photoluminescence up to at Least 523 K in ASnI3 Perovskites (A = Cs+, CH3NH3 + and NH2-CHNH2 +)

Athanassios G. Kontos, Andreas Kaltzoglou, Michalis K. Arfanis, Kyle M. McCall, Constantinos C. Stoumpos, Bruce W. Wessels, Polycarpos Falaras, Mercouri G Kanatzidis

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

We report temperature-dependent photoluminescence (PL) in polycrystalline ASnI3 perovskites (A = Cs+, CH3NH3 +, and HC(NH2)2 +), demonstrating extremely robust emission up to very high temperatures (523 K for CsSnI3). The PL peak energy (EPL) monotonically blueshifts with increasing temperature, indicating band gap widening. Variable temperature synchrotron powder X-ray diffraction analysis confirms that these changes are associated with progressive emphanitic off-centering and dynamic fluctuations of the perovskite lattice. In CsSnI3, three different temperature gradients of EPL are defined (0.29 meV K-1 below 200 K, 0.17 meV K-1 from 200 to 400 K, and 0.48 meV K-1 above 400 K), commensurate with the onset of dynamic structural disorder at 200 K and its saturation at 400 K as the Cs+ atoms rattle independently of the [SnI3]- perovskite lattice. These results explain how solution-processed perovskites with massive defect concentrations can yield high optoelectronic performance at elevated temperatures.

Original languageEnglish
Pages (from-to)26353-26361
Number of pages9
JournalJournal of Physical Chemistry C
Volume122
Issue number46
DOIs
Publication statusPublished - Nov 21 2018

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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