An Unusual Phase Transition Driven by Vibrational Entropy Changes in a Hybrid Organic–Inorganic Perovskite

Wenjun Wei, Keith Butler, Guoqiang Feng, Christopher J. Howard, Wei Li, Michael Carpenter, Peixiang Lu, Aron Walsh, Anthony K. Cheetham

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Abstract

The driving forces for the phase transitions of ABX3 hybrid organic–inorganic perovskites have been limited to the octahedral tilting, order–disorder, and displacement. Now, a complex structural phase transition has been explored in a HOIP, [CH3NH3][Mn(N3)3], based on structural characterizations and ab initio lattice dynamics calculations. This unusual first‐order phase transition between two ordered phases at about 265 K is primarily driven by changes in the collective atomic vibrations of the whole lattice, along with concurrent molecular displacements and an unusual octahedral tilting. A significant entropy difference (4.35 J K−1 mol−1) is observed between the low‐ and high‐temperature structures induced by such atomic vibrations, which plays a main role in driving the transition. This finding offers an alternative pathway for designing new ferroic phase transitions and related physical properties in HOIPs and other hybrid crystals.
Original languageEnglish
Pages (from-to)8932-8936
Number of pages5
JournalAngewandte Chemie-International Edition
Volume57
Issue number29
DOIs
Publication statusPublished - 16 Jul 2018

Keywords

  • ab initio lattice dynamics calculations
  • hybrid organic–inorganic perovskites
  • phase transitions
  • vibrational entropy

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)

Cite this

Wei, W., Butler, K., Feng, G., Howard, C. J., Li, W., Carpenter, M., Lu, P., Walsh, A., & Cheetham, A. K. (2018). An Unusual Phase Transition Driven by Vibrational Entropy Changes in a Hybrid Organic–Inorganic Perovskite. Angewandte Chemie-International Edition, 57(29), 8932-8936. https://doi.org/10.1002/anie.201803176