A single molecule elevates solar module output and stability

A single molecule elevates solar module output and stability
by Sophie Jenkins
London, UK (SPX) Apr 24, 2025

A new molecule developed through international collaboration has been shown to significantly improve both the performance and durability of perovskite solar cells, according to a recent study published in *Science*. The discovery centers on a synthetic ionic salt named CPMAC, which originates from buckminsterfullerene (C60) and has been shown to outperform traditional C60 in solar applications.

Researchers from the King Abdullah University of Science and Technology (KAUST) played a key role in the development of CPMAC. While C60 has long been used in perovskite solar cells due to its favorable electronic properties, it suffers from stability issues caused by weak van der Waals interactions at the interface with the perovskite layer. CPMAC was engineered to address these shortcomings.

"For over a decade, C60 has been an integral component in the development of perovskite solar cells. However, weak interactions at the perovskite/C60 interface lead to mechanical degradation that compromises long-term solar cell stability. To address this limitation, we designed a C60-derived ionic salt, CPMAC, to significantly enhance the stability of the perovskite solar cells," explained Professor Osman Bakr, Executive Faculty of the KAUST Center of Excellence for Renewable Energy and Sustainable Technologies (CREST).

Unlike C60, CPMAC forms ionic bonds with the perovskite material, strengthening the electron transfer layer and thereby enhancing both structural stability and energy output. Cells incorporating CPMAC demonstrated a 0.6% improvement in power conversion efficiency (PCE) compared to those using C60.

Though the gain in efficiency appears modest, the impact scales up dramatically in real-world energy production. "When we deal with the scale of a typical power station, the additional electricity generated even from a fraction of a percentage point is quite significant," said Hongwei Zhu, a research scientist at KAUST.

Beyond efficiency gains, CPMAC also enhanced device longevity. Under accelerated aging tests involving high heat and humidity over 2,000 hours, solar cells containing CPMAC retained a significantly higher portion of their efficiency. Specifically, their degradation was one third that observed in cells using conventional C60.

Further performance evaluation involved assembling the cells into four-cell modules, offering a closer approximation to commercial-scale solar panels. These tests reinforced the molecule's advantage in both durability and output.

The key to CPMAC's success lies in its capacity to reduce defects within the electron transfer layer, thanks to the formation of robust ionic bonds. This approach circumvents the limitations posed by van der Waals forces typical of unmodified C60 structures.

Research Report:C60-based ionic salt electron shuttle for high-performance inverted perovskite solar modules