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Title: Structures, Phase Transitions and Tricritical Behavior of the Hybrid Perovskite Methyl Ammonium Lead Iodide

Here, we examine the crystal structures and structural phase transitions of the deuterated, partially deuterated and hydrogenous organic-inorganic hybrid perovskite methyl ammonium lead iodide (MAPbI 3) using time-of-flight neutron and synchrotron X-ray powder diffraction. Near 330 K the high temperature cubic phases transformed to a body-centered tetragonal phase. The variation of the order parameter Q for this transition scaled with temperature T as Q (T c-T) , where T c is the critical temperature and the exponent was close to , as predicted for a tricritical phase transition. We also observed coexistence of the cubic and tetragonal phases over a range of temperature in all cases, demonstrating that the phase transition was in fact first-order, although still very close to tricritical. Upon cooling further, all the tetragonal phases transformed into a low temperature orthorhombic phase around 160 K, again via a first-order phase transition. Finally, based upon these results, we discuss the impact of the structural phase transitions upon photovoltaic performance of MAPbI 3 based solar cells.
 [1] ;  [2] ;  [3] ;  [1] ;  [1] ;  [2] ;  [4]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical and Engineering Materials Division
  2. Dupont Electronics and Communication Technologies, Wilmington, DE (United States)
  3. Dupont Electronics and Communication Technologies, Wilmington, DE (United States); Argonne National Lab. (ANL), Lemont, IL (United States). Advanced Photon Source
  4. Dupont Central Research and Development, Wilmington, DE (United States); Univ. of Delaware, Newark, DE (United States). Dept. of Physics and Astronomy
Publication Date:
Grant/Contract Number:
AC05-00OR22725; AC02-06CH11357
Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 6; Journal Issue: 21 Oct; Journal ID: ISSN 2045-2322
Nature Publishing Group
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
OSTI Identifier: