Related Experiment Video
Updated: Aug 1, 2025
06:26
Orientational Transition in a Liquid Crystal Triggered by the Thermodynamic Growth of Interfacial Wetting Sheets
Published on: May 15, 2017
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Phase Transition Kinetics of MAPbI3 for Tetragonal-to-Orthorhombic Evolution
Jiawei Wu1, Jianfu Chen1, Haifeng Wang1
1Key Laboratory for Advanced Materials, Center for Computational Chemistry and Research Institute of Industrial Catalysis, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China.
JACS Au
|May 1, 2023
Summary
Understanding methylammonium lead iodide (MAPbI3) phase transitions is key to preventing photovoltaic degradation. This study reveals a low-energy pathway driven by PbI6 tilting and MA+ rotation, crucial for stabilizing perovskite solar cells.
Area of Science:
- Materials Science
- Solid-State Physics
- Photovoltaics
Background:
- Methylammonium lead iodide (MAPbI3) perovskites are promising for solar cells but suffer from phase instability.
- The atomic-level kinetics of MAPbI3's tetragonal-to-orthorhombic phase transition, leading to degradation, remain poorly understood.
Purpose of the Study:
- To elucidate the atomic-level mechanism and kinetics of the MAPbI3 phase transition.
- To identify strategies for stabilizing MAPbI3 and improving solar cell performance.
Main Methods:
- Development of a stepwise Nudged Elastic Band (NEB) method to simulate the phase transition pathway.
- Computational analysis of atomic movements, energy barriers, and structural changes during the transition.
Main Results:
- A nonsynergistic minimum-energy pathway for the tetragonal-to-orthorhombic phase transition was identified.
- The transition is driven by PbI6 octahedral tilting and sequential MA+ cation reorientations, with a low energy barrier of 0.08 eV/unit.
- Low-temperature transition is facile, and rotational entropies significantly influence high-temperature transitions.
Conclusions:
- The identified phase transition mechanism explains MAPbI3 instability and degradation.
- Introducing large organic cations can stabilize the low-temperature phase, enhancing the performance of MAPbI3 solar cells.
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