Thermal Disorder-Induced Strain and Carrier Localization Activate Reverse Halide Segregation
Nursultan Mussakhanuly1, Arman Mahboubi Soufiani2, Stefano Bernardi3
1Australian Centre for Advanced Photovoltaics, School of Photovoltaic and Renewable Energy Engineering, University of New South Wales (UNSW), Sydney, 2052, Australia.
Advanced Materials (Deerfield Beach, Fla.)
|December 7, 2023
Summary
Heat-induced reversal of halide ions in perovskites is driven by polaron localization and thermal disorder-induced strain (TDIS). These factors reduce light-induced strain (LIS), promoting stability under operating conditions.
Area of Science:
- Materials Science
- Solid-State Physics
- Photovoltaics
Background:
- Halide ion migration in perovskites is crucial for device stability but its heat-induced reversal mechanism is unclear.
- Light-induced strain (LIS) drives segregation, impacting perovskite performance.
- Understanding reversal mechanisms is key for developing stable perovskite solar cells.
Purpose of the Study:
- To elucidate the underlying mechanism of heat-induced reversal of halide ions in perovskites.
- To investigate the interplay between dynamic disorder, self-trapped polarons, and thermal disorder-induced strain (TDIS).
- To determine the conditions promoting strain homogenization for enhanced perovskite stability.
Main Methods:
- In situ temperature-dependent measurements.
- Computational simulations.
- Analysis of polaron localization and strain dynamics.
Main Results:
- Dynamic disorder-induced polaron localization and TDIS were identified as co-drivers of reversal.
- Polaron localization significantly reduces carrier density, mitigating LIS impact.
- TDIS exceeding LIS effectively masks photoexcitation-induced strain gradients, promoting reversal.
Conclusions:
- Entropy contribution to free energy dominates under reversal conditions, driven by TDIS.
- Strain homogenization is critical for designing stable perovskites for real-world applications.
- Findings provide insights into controlling ion migration for improved perovskite device longevity.
Keywords:
carrier localizationhalide segregation/reversalmixed-halide wide-bandgap perovskitestrainthermal/dynamic-disorderMore Related Videos
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