Polar Species for Effective Dielectric Regulation to Achieve High-Performance CsPbI₃ Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Solid-State Physics

Background:

• Defects in perovskite solar cells (PSCs) cause nonradiative losses, hindering efficiency and stability.
• Current research focuses on reducing and passivating defects, neglecting defect-capture capacity.

Purpose of the Study:

• To investigate and modulate the defect-capture capacity of perovskite materials.
• To enhance the performance and stability of PSCs by minimizing defect-capture radius.

Main Methods:

• Systematic examination of defect-capture capacity.
• Design of highly polarized fluorinated species to alter perovskite dielectric properties.
• Modification of all-inorganic CsPbI3 PSCs with fluorinated species.

Main Results:

• Fluorinated species enhanced dielectric screening, reducing defect-capture radius.
• Fluorinated iodized salt replenished I-vacancy defects, lowering defect density.
• Achieved 20.5% power-conversion efficiency, 1.2 V open-circuit voltage, and 82.87% fill factor in CsPbI3 PSCs.
• Improved humidity tolerance and long-term stability due to hydrophobic effect.

Conclusions:

• The developed strategy effectively regulates defect-capture radius.
• This approach significantly enhances optoelectronic performance and stability of PSCs.
• Provides a general method for improving PSCs by controlling defect interactions.