Synergistic Co-Passivation via Ultrasmall Molecules for Efficient and Stable Perovskite Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Defect passivation is crucial for minimizing charge recombination in perovskite solar cells (PSCs).
• Conventional passivation methods using Lewis base molecules face limitations due to weak bonding and steric hindrance.

Purpose of the Study:

• To introduce a novel molecular engineering strategy for defect passivation at the SnO2/perovskite interface.
• To enhance the performance and stability of PSCs through synergistic defect passivation.

Main Methods:

• Employing ultrasmall-sized potassium diformate and potassium phosphate for co-modification of the SnO2 layer.
• Characterizing interfacial trap density, surface energy, perovskite grain size, and ion migration.

Main Results:

• Reduced trap density by approximately 50% via C=O and P=O group passivation.
• Increased average perovskite grain size from 780 nm to 1370 nm.
• Achieved a champion power conversion efficiency of 24.42% and 92% retention after 2100 hours.

Conclusions:

• Synergistic passivation with potassium diformate and phosphate effectively addresses interfacial defects in PSCs.
• The co-modification strategy enhances device efficiency, stability, and suppresses hysteresis.
• This approach offers a promising pathway for developing high-performance and durable perovskite solar cells.