Defect-Targeted Repair for Efficient and Stable Perovskite Solar Cells Using 2-Chlorocinnamic Acid

Area of Science:

• Materials Science
• Renewable Energy
• Solid-State Chemistry

Background:

• Metal halide perovskites are promising for efficient, low-cost solar cells.
• Defects in perovskite films limit performance and long-term stability.
• Passivation strategies are crucial for overcoming these limitations.

Purpose of the Study:

• To develop a defect-targeted passivation strategy for perovskite solar cells (PSCs).
• To enhance both the efficiency and stability of PSCs using 2-chlorocinnamic acid (2-Cl).
• To investigate the mechanism of defect passivation and its impact on device performance.

Main Methods:

• Utilized 2-chlorocinnamic acid (2-Cl) for defect passivation in formamidinium-cesium lead halide (FACs) perovskite films.
• Systematically investigated the effects of 2-Cl on crystallization kinetics, film morphology, and optoelectronic properties using various characterization techniques.
• Fabricated inverted (p-i-n) PSCs incorporating the optimized FACs absorber layer.

Main Results:

• 2-Cl effectively passivated surface and interfacial defects by coordinating with Pb2+ ions and forming Pb-Cl bonds.
• Optimized FACs perovskite solar cells achieved a champion power conversion efficiency (PCE) of 22.58% with high open-circuit voltage (1.14 V) and fill factor (82.8%).
• Unencapsulated devices demonstrated excellent stability, retaining 90% of initial PCE after 30 days in ambient air and 83% after prolonged illumination stress.

Conclusions:

• Dual-site molecular passivation with 2-Cl is a viable strategy for simultaneously enhancing efficiency and stability in perovskite solar cells.
• The findings highlight the practical potential of this approach for developing durable perovskite photovoltaics.
• This work contributes to advancing the commercial viability of perovskite solar technology.