Bifunctional Molecular Bridge with Tunable Dielectric Constant for Air‐Processed Perovskite Solar Cells

Why It Matters

Surpassing 25% efficiency without a glovebox cuts production costs and speeds commercial adoption of perovskite photovoltaics. The combined chemical passivation and dielectric screening also solves the long‑standing stability hurdle that has limited market entry.

Key Takeaways

• EAP delivers 25.22% efficiency, highest for air‑processed n‑i‑p PSCs
• Dual active sites simultaneously passivate defects and provide dielectric screening
• Dielectric constant tuning controls crystallization and reduces residual stress
• Devices retain 95% efficiency after 4,392 h storage in ambient air
• Stability maintained under 1,000 h MPPT at 40 °C, 40‑50% RH

Pulse Analysis

Perovskite solar cells have attracted intense interest because they can rival silicon in efficiency while using low‑cost, solution‑based processes. However, manufacturing in ambient air has been hampered by moisture‑induced defects, especially at buried interfaces such as SnO2/perovskite. Traditional approaches focus on chemical passivation alone, leaving dielectric mismatches that still impair charge extraction and accelerate degradation. The industry therefore seeks a holistic interface engineering method that can be applied outside a glovebox.

The study introduces two bifunctional molecules—ethanolamine sulfate (EAS) and ethanolamine phosphate (EAP)—designed with tunable dielectric constants and dual anchoring groups. These molecules form a molecular bridge that simultaneously neutralizes uncoordinated Sn4+ and Pb2+ sites while providing a high‑k dielectric layer that screens electric fields. By adjusting the dielectric constant, the researchers control nucleation rates, yielding uniform perovskite grains and relieving residual stress. The result is a marked improvement in carrier lifetime and reduced trap density, which together boost power conversion efficiency.

Achieving a 25.22% efficiency for air‑processed n‑i‑p perovskite cells positions this approach among the top performers worldwide and demonstrates that high‑performance devices can be fabricated without expensive inert‑atmosphere equipment. The reported 95% efficiency retention after 4,392 hours of storage and under prolonged maximum power point tracking underscores the method’s relevance for commercial reliability. As the photovoltaic market looks for scalable, low‑cost alternatives, the dual‑function molecular bridge concept offers a clear pathway to bridge the gap between laboratory breakthroughs and large‑scale production.