Related Experiment Video
Updated: May 6, 2026
08:12
Low Pressure Vapor-assisted Solution Process for Tunable Band Gap Pinhole-free Methylammonium Lead Halide Perovskite Films
Published on: September 8, 2017
8.9K
Mixed Cation-Ordering-Driven Ferroelastic Phase Transition in Hybrid Lead Halide Enabling Large Switchable
Yikun Fu1,2, Xiaoqi Li1,3, Yan Fu1,2
1State Key Laboratory of Functional Crystals and Devices, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China.
Inorganic Chemistry
|May 5, 2026
Summary
Researchers developed a novel 2D hybrid halide material enabling ferroelastic phase transitions. This breakthrough facilitates switchable birefringence, paving the way for advanced optical smart materials.
Area of Science:
- Materials Science
- Solid-State Chemistry
- Crystallography
Background:
- Solid-state phase transition materials are key for stimuli-responsive smart devices.
- Achieving reversible phase transitions in hybrid halides with aromatic cations is challenging due to rigid frameworks.
Purpose of the Study:
- To develop a novel 2D hybrid halide material exhibiting ferroelastic phase transition.
- To enable switchable birefringence in hybrid metal halides through structural engineering.
Main Methods:
- Mixed cation-ordering strategy using (N-methyl-p-toluidine)(2-bromoethylamine)PbBr4.
- Incorporation of a flexible secondary cation to soften the lattice.
- Investigating the ferroelastic phase transition at 353 K and its effect on optical properties.
Main Results:
- A two-dimensional hybrid halide ferroelastic phase transition material, (NMPA)(BrEA)PbBr4, was successfully synthesized.
- A ferroelastic phase transition (4/mmmFmmm) was observed at 353 K, driven by lattice softening and dynamic disorder.
- The material demonstrated a reversible switchable birefringence response (Δn from 0.028 to 0) linked to the ferroelastic transition.
Conclusions:
- The developed material shows significant potential for optical applications, particularly in switchable birefringence.
- The mixed cation-ordering strategy offers an effective route for designing hybrid metal halides with tunable optical properties.
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