A research team at Ulsan National Institute of Science and Technology (UNIST) in Korea has achieved a major breakthrough by developing a cutting-edge modular artificial leaf that simultaneously meets the requirements of high efficiency, long-term stability, and scalability—a critical step forward in green hydrogen production technology essential for achieving carbon neutrality. The findings have been published in Nature Communications.

This innovative system was jointly led by Professor Jae Sung Lee, Professor Sang Il Seok, and Professor Ji-Wook Jang from the School of Energy and Chemical Engineering. Mimicking natural leaves, the artificial leaf produces hydrogen using only sunlight and water, requiring no external power source and emitting zero carbon dioxide—a truly clean hydrogen production method.

Unlike conventional photovoltaic-electrochemical (PV-EC) systems that generate electricity first and then produce hydrogen, this artificial leaf directly converts solar energy into chemical energy, minimizing losses associated with resistance and drastically reducing installation footprint. However, previous challenges in efficiency, durability, and scalability have hindered commercial deployment.

To overcome these issues, the team fabricated high-performance 1cm² perovskite-based photoelectrodes using a chlorine-doped formamidinium lead triiodide (Cl:FAPbI₃) absorber layer and a UV-insensitive chlorine-doped tin oxide (Cl:SnO₂) electron transport layer. These units were then assembled into a 4×4 array to create a scalable modular system capable of stably producing hydrogen using only sunlight.

Notably, the entire module achieved a solar-to-hydrogen (STH) conversion efficiency of 11.2% under unbiased one-sun illumination—surpassing the widely recognized 10% threshold for commercial viability.

The team attributes this high performance and stability to the strategic combination of the chlorine-doped perovskite absorber, UV-resistant electron transport layer, and a NiFeCo catalyst. To ensure device durability, specialized nickel foil and resin encapsulation techniques were employed. With these measures, the device operated continuously for 140 hours while retaining 99% of its initial performance.

Professor Jae Sung Lee emphasized: "This achievement goes beyond laboratory-scale demonstration. Component-level efficiency exceeding 10% is a key milestone toward real-world applications." He further added: "The artificial leaf can be scaled up to larger panels similar to photovoltaic modules, marking a decisive step toward commercial deployment."

More information: Dharmesh Hansora et al., Scalable and durable module-sized artificial leaf with >10% solar-to-hydrogen efficiency, Nature Communications (2025).

This breakthrough by the UNIST team in Korea brings new hope to green hydrogen production technology and is expected to accelerate its practical implementation, contributing significantly to the realization of carbon neutrality goals.