Moisture‑resistant scalable ambient‑air crystallization of perovskite films via self‑buffered molecular migration strategy

As perovskite solar cells (PSCs) move toward commercialization, their extreme sensitivity to ambient moisture remains a major barrier to scalable, low-cost manufacturing. Now, researchers from Xidian University, led by Prof. Weidong Zhu and Prof. Chunfu Zhang, have developed a self-buffered molecular migration strategy that enables moisture-resistant, ambient-air crystallization of perovskite films—achieving record efficiencies without the need for strict humidity control.

Why Self-Buffered Molecular Migration Matters

• Moisture Tolerance: A BABr shielding layer slows intermolecular exchange between perovskite intermediates and ambient moisture, suppressing premature crystallization and impurity formation.
• Broad Process Windows: Enables high-quality film formation under 60–80% relative humidity and extended air exposure times (up to 60 min).
• Scalable and Cost-Effective: Eliminates the need for glovebox environments and tight humidity control, reducing manufacturing complexity and cost.

Innovative Design and Features

• Surface Shielding Layer: n-Butylammonium bromide (BABr) forms a hydrophobic barrier that modulates solvent–moisture interactions during ambient annealing.
• Enhanced Crystallinity: Promotes larger grain size, higher phase purity, and reduced defect density in final perovskite films.
• Versatile Chemistry: Strategy successfully extended to other shielding agents (MACl, PEACl, CF₃-PEABr, etc.) and multiple bandgaps (1.53, 1.68, 1.77 eV).

Applications and Performance

• Record Efficiency: 1.68 eV-bandgap PSCs achieve 22.09% PCE in ambient air (50–60% RH), the highest reported for this bandgap under air processing.
• Excellent Stability: Retains 94% of initial PCE after 1000 h in 60–80% RH, outperforming control devices.
• High Reproducibility: Devices fabricated across 30–80% RH and 10–55 min air exposure consistently exceed 20.5% PCE.

Conclusion and Outlook

This work introduces a universal, scalable strategy for ambient-air perovskite crystallization, unlocking wider processing windows, higher efficiencies, and improved stability for next-generation photovoltaic manufacturing. It marks a critical step toward industrial-grade perovskite solar cells processed in open air.

Stay tuned for more innovations from Prof. Weidong Zhu and Prof. Chunfu Zhang’s team at Xidian University!