Unlocking the Ambient Temperature Effect on FA-Based Perovskites Crystallization by In Situ Optical Method

Area of Science:

• Materials Science
• Renewable Energy
• Crystallization Dynamics

Background:

• Multiple cation-composited perovskites enhance perovskite solar cell (PSC) performance and stability.
• Laboratory-scale fabrication methods for high-performance perovskites are often not scalable due to sensitivity to processing conditions.

Purpose of the Study:

• Investigate the effect of ambient temperature on the crystallization process of multiple cation-composited perovskites.
• Identify factors limiting the large-scale production of high-quality formamidinium (FA)-based perovskite films.

Main Methods:

• Utilized an in situ optical method to monitor perovskite crystallization.
• Analyzed the crystallization process of methylammonium lead iodide (MAPbI3) and formamidinium lead iodide (FAPbI3) under varying ambient temperatures and FA content.

Main Results:

• Formamidinium lead iodide (FAPbI3) lacks the solvent-coordinated intermediate phase seen in methylammonium lead iodide (MAPbI3), with nucleation nearly complete post-spin-coating.
• Noticeable nuclei aggregation, typically seen during annealing in MAPbI3, occurs during spin-coating in FA-based perovskites, exacerbated by higher temperatures or FA content.
• Proposed aggregation-induced solute depletion, not stress release, as the cause of cracks in FA-based perovskites.

Conclusions:

• Revealed critical limiting factors for achieving high-quality FA-based perovskite films.
• Provided insights into the narrow processing window for large-scale perovskite solar cell production.
• Highlighted the importance of controlling ambient temperature and FA content during fabrication.