Related Experiment Video
Updated: Jun 8, 2026
12:37
Phase Diagram Characterization Using Magnetic Beads as Liquid Carriers
Published on: September 4, 2015
Mechanistic insight into α-to-δ phase transition and stabilizing α-phase FAPbI3 via regulating δ-phase orientation
Chuwu Xing1, Yongzhe Li2, Qinhui Bao1
1Ministry of Education Key Laboratory for Green Preparation and Application of Functional Materials, School of Materials Science and Engineering, Hubei University, Wuhan, China.
Nature Communications
|June 6, 2026
Summary
Formamidinium-based perovskite instability is caused by phase transitions. Introducing 2D materials creates interfaces that enhance stability, leading to efficient and durable perovskite solar cells.
Area of Science:
- Materials Science
- Solid-State Physics
- Photovoltaics
Background:
- Formamidinium-based perovskites exhibit structural instability due to a spontaneous α-to-δ phase transition.
- Current strategies to suppress this transition are limited by an incomplete understanding of the underlying physical mechanisms.
Purpose of the Study:
- To elucidate the physical mechanisms driving the α-to-δ phase transition in formamidinium-based perovskites.
- To develop a novel strategy for stabilizing these perovskites and improving solar cell performance.
Main Methods:
- Investigated the role of interfacial strain between α-phase (011) and δ-phase (110) planes as active sites for phase transition.
- Introduced two-dimensional (2D) perovskitoid materials into the perovskite matrix to create 2D/δ interfaces.
- Analyzed the impact of interfacial strain on δ-phase orientation and α/δ transition interface formation.
Main Results:
- Identified the coherent interface with tensile strain between α-phase (011) and δ-phase (110) planes as the key site for α-to-δ phase transition.
- Demonstrated that 2D perovskitoids form a 2D/δ interface, inducing large interfacial strain that disrupts δ-phase orientation.
- Showcased enhanced α-phase stability, leading to formamidinium-based perovskite solar cells with 25.61% efficiency.
- Achieved 90% initial efficiency retention after 1,000 hours of unencapsulated operation under 70% relative humidity.
Conclusions:
- Provided a mechanistic understanding of the α-to-δ phase transition in formamidinium-based perovskites.
- Established a universally applicable strategy using 2D perovskitoids to enhance the stability of formamidinium-based perovskites.
- Paved the way for more durable and efficient perovskite solar cell technologies.
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