Molecular Locking Strategy Enables Efficient and Scalable OSCs

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Prof. GE Ziyi's group from the Ningbo Institute of Materials Technology and Engineering (NIMTE) of the Chinese Academy of Sciences (CAS) has developed a molecular locking strategy to stabilize the interface between the electrode and the hole-transport layer in organic solar cells (OSCs), enabling large-area, highly efficient, and stable photovoltaic devices.

The study was published in Joule on October 21.

OSCs are devices that convert sunlight into electricity using carbon-based organic materials rather than the silicon used in conventional solar panels. OSCs feature solution processability, mechanical flexibility, low-cost fabrication, and compatibility with large-area manufacturing. They also deliver impressive laboratory efficiencies, making them a leading candidate for next-generation photovoltaics.

However, forming dense, stable self-assembled monolayer (SAM) contacts on indium tin oxide (ITO) surfaces remains challenging. These contacts tend to desorb under continuous light and heat, thus limiting the commercial application of OSCs on a large scale.

To address this unstable interface issue, researchers at NIMTE proposed a molecular locking strategy. Using a vacuum-deposited InClx interlayer, they triggered ligand exchange to form a robust multidentate In-O-P coordination network that densely and uniformly anchors SAMs.

Based on this molecular locking interface, small-area OSCs developed by the researchers achieved a power conversion efficiency (PCE) of 20.4%.

"We scaled the technique to large-area modules with an aperture area of 15.6 cm², reaching an active-area PCE of 18.8%, one of the highest reported values for SAM-based organic photovoltaic modules," said Prof. LIU Quan, a corresponding author of the study.

The devices also retained over 85% of their initial efficiency after 2,000 hours of maximum power point tracking at 25 °C, demonstrating excellent stability.

This strategy provides a universal interface platform for efficient, stable, and scalable organic photovoltaic modules, showing promise for overcoming the long-standing trade-off between efficiency, stability, and scalability.