New Energies, new possibilities

Record-high solar-to-hydrogen efficiency achieved without external power—commercialization gets closer

In the race toward carbon-neutral energy, a major milestone has emerged from South Korea. Researchers at UNIST (Ulsan National Institute of Science and Technology) have developed a next-generation modular artificial leaf that generates hydrogen directly from sunlight and water—without external electricity or carbon emissions.

The technology, inspired by natural photosynthesis, is designed to produce green hydrogen, a clean fuel hailed as a future alternative to fossil energy. Unlike conventional solar panel-electrolysis systems, the artificial leaf skips the electrical conversion step altogether, converting sunlight directly into chemical energy.

This simplified design reduces system losses and spatial footprint, yet has long been hindered by issues of low efficiency, limited durability, and poor scalability.

UNIST’s team, led by Professors Jae Sung Lee, Sang Il Seok, and Ji Wook Jang, has overcome these barriers by developing a perovskite-based photoelectrode enhanced with nickel-iron-cobalt catalysts. The result: a modular 4×4 array system that achieved a record 11.2% solar-to-hydrogen conversion efficiency—the highest ever reported at the module level.

“This is a pivotal breakthrough,” the researchers said. “Exceeding the 10% efficiency mark with a scalable unit proves that commercial applications are no longer theoretical.”

The team’s success lies in the material science: A chlorine-doped perovskite absorber ensures light capture, while UV-resistant transport layers and advanced catalyst protection preserve long-term stability. The modules maintained 99% of their original performance after 140 hours of continuous operation under sunlight and moisture.

Crucially, the modular leaf system can be scaled into large-area panels, similar to conventional solar arrays—an essential step toward real-world deployment.

The research, published in the May 6 issue of Nature Communications, was funded by Korea’s Ministry of Science and ICT through its climate change response and researcher exchange programs, as well as by the Institute for Basic Science (IBS).

As governments and industries seek viable alternatives to carbon-intensive energy, Korea’s artificial leaf may soon emerge as a key player in the global hydrogen economy.