A modular artificial photosynthesis device with an efficiency of 11.2% has been developed, which secures long-term stability and large-area scalability by directly producing green hydrogen using solar energy.

A research team led by Professors Jae-Seong Lee, Sang-Il Seok, and Ji-Wook Jang from the Department of Energy and Chemical Engineering at UNIST (Ulsan National Institute of Science and Technology) has brought the modular artificial leaf (artificial photosynthesis) technology that directly produces green hydrogen by converting solar energy into water decomposition to a commercializable level.

This module, developed by combining 16 1㎠ high-efficiency photoelectrodes into one, generates hydrogen by converting photonic energy into chemical energy without separate power, and achieved a 'Solar to Hydrogen Efficiency (STH)' of 11.2% for the entire module.

Artificial leaves are a technology that mimics natural photosynthesis and produces hydrogen using only sunlight and water, and do not emit any carbon dioxide during the green hydrogen production process.

Unlike the existing solar cell-based electrolysis (PV-EC) method, it has the advantage of no energy loss between the generator and the electrolyzer and can reduce the installation area.

The research team created a 1㎠ unit photoelectrode by combining a Cl:FAPbI₃ (chlorine-doped perovskite) light-absorbing layer, a Cl:SnO₂ electron-transport layer with excellent UV resistance, and a Ni-Fe-Co alloy catalyst (NiFeCo).

Modules connected in a 4x4 array are powered by solar energy alone, without the need for a separate external power source. Stable hydrogen production is possible, and the efficiency has surpassed the commercialization standard of 10% in module units beyond laboratory scale.

Damage to the photoelectrode caused by moisture and oxygen was minimized by applying special nickel foil and resin encapsulation technology.

Its high durability was proven by maintaining 99% of the initial efficiency in a 140-hour continuous operation test.

Professor Lee Jae-seong emphasized, “This has laid a critical foundation for the production of modules for commercial hydrogen production, as it can be expanded to large-area artificial photosynthesis panels.”

This study was published in Nature Communications (IF 14.7) on May 6, 2025. This achievement, which was carried out through the Ministry of Science and ICT's Climate Change Response Project, BrainLink Project, and the Institute for Basic Science (IBS), is evaluated to have greatly increased the possibility of commercializing solar green hydrogen production.