High Performance Inverted RbCsFAPbI₃ Perovskite Solar Cells Based on Interface Engineering and Defects Passivation.

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Lead halide perovskites solar cells (PSCs) offer high efficiency and low cost.
• Methylammonium (MA)-free and bromide (Br)-free formamidine perovskites are crucial for thermal stability and desired optical properties.
• The hole transporting layer (HTL) significantly impacts inverted p-i-n PSC performance.

Purpose of the Study:

• To optimize charge carrier dynamics and defect chemistry in MA-free, Br-free perovskite absorbers.
• To enhance the efficiency and stability of formamidine lead iodide perovskite solar cells.
• To investigate the role of a NiOₓ/PTAA bi-layer HTL with additive and passivation engineering.

Main Methods:

• Employed a NiOₓ/PTAA bi-layer hole transporting layer.
• Utilized guanidinium hydrochloride (GuHCl) additive engineering.
• Applied phenylethylammonium iodide (PEAI) passivation strategy.
• Fabricated MA-free, Br-free RbCsFAPbI₃-based perovskite solar cells.

Main Results:

• Achieved a power conversion efficiency of 22.78%.
• Demonstrated enhanced charge carrier dynamics and tuned defect chemistry.
• The device retained 95% of its initial performance after 500 hours of continuous 1-sun equivalent LED illumination at 45 °C.

Conclusions:

• The NiOₓ/PTAA bi-layer HTL, combined with GuHCl additive and PEAI passivation, effectively optimizes MA-free, Br-free perovskite solar cells.
• The developed strategies lead to high efficiency and improved operational stability.
• This work contributes to the advancement of stable and efficient perovskite solar cell technology.