Over 21% Efficient Cesium Lead Triiodide Solar Cell Enabled by Molten Salt Accelerating the Crystallization Processes

Area of Science:

• Materials Science
• Solid-State Chemistry
• Photovoltaics

Background:

• High-quality cesium lead iodide (CsPbI3) is crucial for efficient solar cells.
• Controlling crystal growth and minimizing defects are key challenges in perovskite film fabrication.

Purpose of the Study:

• To investigate the impact of cesium formate (CsFo) on CsPbI3 thin film quality.
• To explore CsFo's role in modifying crystallization and defect passivation.

Main Methods:

• Introduction of cesium formate (CsFo) during CsPbI3 thin film preparation.
• Analysis of crystallization processes and defect passivation mechanisms.

Main Results:

• CsFo's low melting point facilitates energy-efficient crystallization.
• Formate anions effectively passivate iodide vacancies in CsPbI3.
• Achieved a steady-state power conversion efficiency of 21.23% and an open-circuit voltage of 1.25 V.

Conclusions:

• Cesium formate is a promising additive for enhancing CsPbI3 perovskite solar cells.
• The strategy improves film quality by optimizing crystallization and reducing defects.
• The achieved performance metrics are among the highest for this class of solar cells.