Cyclic Multi-Site Chelation for Efficient and Stable Inverted Perovskite Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Perovskite solar cells (PSCs) face challenges from non-radiative recombination and moisture degradation.
• High-quality perovskite bulk is crucial for efficient and stable PSCs.

Purpose of the Study:

• To mitigate trap-assisted recombination and moisture-induced degradation in inverted (p-i-n) PSCs.
• To enhance perovskite quality using covalent organic frameworks (COFs).

Main Methods:

• Integrating thermally stable perovskite layers with Lewis base COFs.
• Utilizing COFs' ordered pore structure and binding groups for chelation with lead ions.
• Employing COFs as n-type dopants to improve surface energy alignment.

Main Results:

• COF integration significantly enhanced perovskite quality in bulk and at grain boundaries.
• Achieved power conversion efficiencies (PCEs) of 25.64% (0.0748 cm² device) and 23.49% (1 cm² device).
• Demonstrated remarkable durability, retaining 81% PCE after 978 hours of accelerated aging at 85°C, with excellent stability under illumination and moisture without encapsulation.

Conclusions:

• COF doping is an effective strategy to improve both efficiency and stability of perovskite solar cells.
• This approach addresses critical limitations in PSC development, paving the way for more robust solar technologies.