Fluorination-Driven Multi-Site Anchoring for Highly Efficient and Stable Perovskite Solar Cells.

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Molecular passivation is key to reducing defects in perovskite solar cells (PSCs).
• Simultaneously suppressing defects and improving charge extraction at interfaces remains a significant challenge.
• Existing passivation methods often struggle to balance these critical interfacial interactions.

Purpose of the Study:

• To develop a novel multi-site anchoring strategy for highly efficient and stable perovskite solar cells.
• To investigate the passivation effects of 3-fluoro-4-(aminomethyl)pyridinium ammonium diiodide (3-F-AMP) on perovskite interfaces.
• To enhance charge extraction and operational stability in perovskite solar cells.

Main Methods:

• A fluorination-driven multi-site anchoring strategy using 3-F-AMP was employed.
• The molecular structure of 3-F-AMP was engineered to modulate dipole and achieve planar geometry for multi-site interaction.
• Interfacial properties, defect mitigation, charge extraction, and device performance were analyzed.

Main Results:

• 3-F-AMP effectively passivated perovskite interfaces, inhibiting residual PbI2 and stabilizing the perovskite lattice.
• Nonradiative recombination was reduced, and a well-matched interface for improved charge extraction was created.
• Champion efficiencies reached 25.82% (1.53 eV) and 22.69% (1.68 eV) perovskites, with 25.07% for large-area (1.24 cm2) devices.
• Markedly improved operational stability under ISOS protocols was observed.

Conclusions:

• The fluorination-driven multi-site anchoring strategy using 3-F-AMP offers a promising route for defect passivation in PSCs.
• This approach significantly enhances photovoltaic performance and operational stability.
• The rational design of multi-site passivators is crucial for the industrialization of perovskite solar cells.