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Elastic and Anelastic Behavior Associated with Structural Transitions in CsPbBr3.
Pingjing Luo1, Zhengwang He2, Dexin Yang1
1Institute of Advanced Magnetic Materials, College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, China.
The Journal of Physical Chemistry Letters
|July 3, 2025
Summary
Strain coupling in cesium lead bromide (CsPbBr3) perovskites impacts their performance. Ultrasound reveals octahedral tilting transitions, elastic softening, and twin wall dynamics influencing optoelectronic properties.
Area of Science:
- Solid State Physics
- Materials Science
- Optoelectronics
Background:
- Strain coupling and relaxation dynamics are crucial for metal halide perovskites' photovoltaic and photoluminescent properties.
- Understanding octahedral tilting transitions is key to optimizing perovskite semiconductor performance.
Purpose of the Study:
- To investigate the elastic and anelastic properties of CsPbBr3 during octahedral tilting transitions.
- To correlate these properties with temperature-dependent structural changes and their impact on optoelectronic behavior.
Main Methods:
- Resonant ultrasound spectroscopy was used to measure elastic and anelastic properties.
- Measurements were conducted on CsPbBr3 over a temperature range of 303-468 K.
Main Results:
- A cubic-to-tetragonal transition near 405 K showed significant elastic softening and increased acoustic loss.
- Mobile ferroelastic twin walls were observed in the tetragonal phase, becoming pinned by lead vacancies around 380 K.
- Elastic softening in the cubic phase correlated with local polar fluctuations, and high attenuation in the orthorhombic phase suggested mobile twin walls.
Conclusions:
- Octahedral tilting transitions in CsPbBr3 significantly affect its elastic and anelastic properties.
- Ferroelastic twin wall dynamics and lead vacancies play a role in the material's behavior.
- Local polar fluctuations and twin wall mobility are linked to the observed acoustic anomalies, impacting optoelectronic performance.
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