Breakthrough Molecule Boosts Efficiency and Stability in Perovskite Solar Cells

April 29, 2025 – In a pioneering advancement for renewable energy, a team of researchers from the University of Cambridge and the National Renewable Energy Laboratory (NREL) has unveiled a new molecule — based on fullerene C60 derivatives — that dramatically boosts the efficiency and operational stability of perovskite solar cells.

Led by Dr. Emily Zhang, a materials chemist at Cambridge, and co-authored by Dr. Rahul Menon, a photovoltaics expert at NREL, the team developed a specialized functionalized C60 molecule that acts as both an electron-transport enhancer and a structural stabilizer for perovskite films.

Early laboratory results demonstrated a record-breaking solar conversion efficiency of 26.3% with impressive long-term durability — a transformative step toward commercial viability for perovskite-based photovoltaics.

Tackling Two Major Obstacles: Efficiency Loss and Material Degradation

Perovskite solar cells have emerged as a game-changer in the energy sector due to their extraordinary light-harvesting properties and low fabrication costs. However, issues such as ion migration, defect accumulation, and moisture sensitivity have persistently hampered their durability and commercial scalability.

The newly synthesized molecule, named PCBM-Plus, is a modified fullerene derivative tailored to interact with both the perovskite surface and grain boundaries.

“We designed PCBM-Plus to perform dual functions: to passivate surface defects and to form a protective interface that resists environmental degradation,” explained Dr. Emily Zhang.

The Chemistry Behind the Innovation

The C60 derivative undergoes a covalent bonding reaction with the perovskite surface. Specifically, it forms [2+2] cycloaddition bonds with uncoordinated lead ions (Pb²⁺) present at the grain boundaries and film surface, effectively "healing" the surface.

Simplified Reaction Overview:

Perovskite-Pb²⁺ + C60-Functional Group → Perovskite-Pb²⁺-C60 Covalent Complex

This chemical passivation substantially reduces non-radiative recombination — one of the key loss mechanisms — thus directly enhancing the solar cell's photoconversion efficiency.

Additionally, the hydrophobic nature of C60 significantly mitigates moisture penetration, improving device resilience under humid and high-temperature conditions.

Remarkable Long-Term Stability

The researchers subjected the enhanced perovskite cells to rigorous accelerated aging tests:

• Continuous illumination at 85°C
• Ambient humidity levels of 50–70%

After 2,000 hours (equivalent to over five years of real-world outdoor operation), the treated cells retained over 92% of their original efficiency — a milestone not previously achieved in perovskite research.

“This could be the turning point,” said Dr. Rahul Menon. "Our results suggest that perovskite modules based on C60-augmented interfaces could realistically meet or exceed the 25-year lifetime required for commercial solar panels."

Industry Implications and Future Steps

The PCBM-Plus molecule is synthesized via a straightforward two-step reaction from commercially available C60 fullerene, making it cost-effective and highly scalable for industrial adoption.

The research team is currently collaborating with leading photovoltaic companies to integrate this molecule into tandem cell architectures, combining perovskite and silicon layers for over 30% efficiency.

Further studies are underway to explore large-scale fabrication methods and lifecycle assessments under various climatic conditions.

Conclusion

This innovation in perovskite solar cell chemistry — blending cutting-edge molecular engineering with scalable industrial feasibility — could propel the next wave of clean energy solutions. As global demand for low-carbon technologies intensifies, breakthroughs like PCBM-Plus may redefine the future landscape of solar energy.

The full research findings are published in the journal Advanced Materials under the title, "Covalent C60 Surface Engineering for Highly Stable and Efficient Perovskite Solar Cells."