Molten-Salt-Assisted CsPbI₃ Perovskite Crystallization for Nearly 20%-Efficiency Solar Cells

Improving crystallization processes is essential for enhancing the performance of perovskite solar cells. Prior research has shown that grain quality and film uniformity significantly impact device efficiency. However, traditional methods like solvent annealing often fail to control crystallization dynamics effectively. This gap motivated the development of alternative strategies. Existing techniques struggle to suppress defects like pinholes and cracks. No prior work had resolved the issue of intermediate phase control during perovskite film formation. The need for better mass transfer mechanisms became clear. Researchers propose exploring alternative chemical environments to influence crystallization pathways. The challenge remains to achieve high-quality films with minimal energy barriers.

The goal of this study is to introduce a novel crystallization strategy for perovskite films. The specific problem is the poor control over grain growth and defect formation in traditional methods. The motivation stems from the need to improve film quality for higher solar cell efficiency. The study aims to manipulate crystallization dynamics using molten salts. This approach may enhance mass transfer and reduce energy barriers. The researchers propose that altering intermediate phases can improve film properties. The study focuses on all-inorganic perovskites like CsPbI₃. The ultimate aim is to achieve high-efficiency solar cells through better crystallization control.

The study employs a molten-salt-assisted crystallization (MSAC) strategy. This method involves introducing molten salts into the perovskite precursor solution. The salts influence mass transfer through convection and diffusion processes. The approach alters intermediate phases during crystallization. Researchers monitor film formation using optical and electrical property analyses. The study compares MSAC with traditional solvent annealing techniques. The process includes controlled temperature and time parameters. The method allows for in-plane grain growth and defect suppression.

The MSAC strategy produces perovskite films with reduced pinholes and cracks. The grain quality improves due to enhanced mass transfer mechanisms. The films exhibit optical and electrical properties suitable for high efficiency. The devices achieve a maximum steady-state efficiency of 19.83%. The open-circuit voltage (Voc) reaches as high as 1.2 V. The Voc deficit is effectively reduced through this method. The crystallization pathway is modified by intermediate phase manipulation. The results suggest that MSAC outperforms traditional solvent annealing.

The MSAC strategy may improve perovskite film quality by altering crystallization dynamics. The method may suppress defects like pinholes and cracks in the films. The study suggests that molten salts influence mass transfer and intermediate phases. The results propose that this approach enhances device performance metrics. The authors suggest that MSAC could be a viable alternative to traditional methods. The findings may support the development of higher-efficiency solar cells. The study proposes that crystallization pathway control is key to film quality. The results align with the authors' claim that this method achieves among the highest efficiencies reported.