Pseudo-halide anion engineering for α-FAPbI₃ perovskite solar cells

Area of Science:

• Materials Science
• Solid-State Chemistry
• Photovoltaics

Background:

• Metal halide perovskites (ABX3) are promising for thin-film photovoltaics.
• Formamidinium lead triiodide (FAPbI3) is a leading semiconductor for efficient and stable perovskite solar cells.
• Defects, particularly anion vacancies, limit perovskite performance.

Purpose of the Study:

• To introduce an anion engineering strategy to suppress defects in perovskite films.
• To enhance the crystallinity and optoelectronic properties of perovskite films.
• To improve the efficiency and stability of perovskite solar cells.

Main Methods:

• Utilized pseudo-halide anion formate (HCOO-) for anion engineering.
• Applied formate to suppress anion-vacancy defects at grain boundaries and surfaces.
• Investigated the impact on perovskite film crystallinity and device performance.

Main Results:

• Successfully suppressed anion-vacancy defects and augmented film crystallinity.
• Achieved a power conversion efficiency of 25.6% (certified 25.2%) for solar cells.
• Demonstrated long-term operational stability (450 hours) and high electroluminescence.

Conclusions:

• Anion engineering with formate effectively eliminates major lattice defects in metal halide perovskites.
• This approach provides facile access to solution-processable films with enhanced optoelectronic performance.
• The findings offer a direct route to highly efficient and stable perovskite solar cells.