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

Wei, Wenjuan and Li, Wei and Butler, Keith T. and Feng, Guoqiang and Howard, Christopher J. and Carpenter, Michael A. and Lu, Peixiang and Walsh, Aron and Cheetham, Anthony K. (2018) An Unusual Phase Transition Driven by Vibrational Entropy Changes in a Hybrid Organic-Inorganic Perovskite. Angewandte Chemie International Edition, 57 (29). pp. 8932-8936. ISSN 14337851 DOI https://doi.org/10.1002/anie.201803176

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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.

Item Type:	Article
Uncontrolled Keywords:	2018AREP, IA72
Subjects:	03 - Mineral Sciences
Divisions:	03 - Mineral Sciences
Journal or Publication Title:	Angewandte Chemie International Edition
Volume:	57
Page Range:	pp. 8932-8936
Identification Number:	https://doi.org/10.1002/anie.201803176
Depositing User:	Sarah Humbert
Date Deposited:	11 Apr 2019 13:25
Last Modified:	11 Apr 2019 13:25
URI:	http://eprints.esc.cam.ac.uk/id/eprint/4468

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