Energetics, Structures, and Phase Transitions of Cubic and Orthorhombic Cesium Lead Iodide (CsPbI3) Polymorphs

Bin Wang, Novendra Novendra, Alexandra Navrotsky

Research output: Contribution to journalArticlepeer-review

81 Scopus citations


Cesium lead iodide (CsPbI3) perovskite has shown great potential as a light absorbing material for solar cell applications. Despite intense research leading to increasing power conversion efficiency, a major problem concerning CsPbI3 lies in the long term stability and interconversion between different CsPbI3 polymorphs, a subject barely studied from the thermodynamic perspective. We report the formation enthalpies of two CsPbI3 polymorphs, α and δCsPbI3, using a combination of room temperature solution calorimetry in dimethyl sulfoxide (DMSO) and differential scanning calorimetry. We show that both polymorphs are stable with respect to their binary halides and confirm that the α-phase is a high temperature polymorph, metastable under ambient conditions. This work sheds light on patterns in polymorphism, possible decomposition reactions, materials stability, and compatibility within halide perovskites and related systems. Thermodynamic instability near ambient temperature of functional perovskites may be a general phenomenon related to their vibrational density of states.

Original languageEnglish (US)
Pages (from-to)14501-14504
Number of pages4
JournalJournal of the American Chemical Society
Issue number37
StatePublished - Sep 18 2019
Externally publishedYes

ASJC Scopus subject areas

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


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