Artificial photosynthesis technology that directly converts solar energy into hydrogen, or an 'artificial leaf', has recently attracted significant attention due to its minimal space requirement and low cost compared to wired photoelectrochemical and photovoltaic-electrochemical systems for solar hydrogen production. However, it remains a challenge to achieve a practical-size solar water-splitting device that can fulfill the criteria of a solar-to-hydrogen conversion efficiency above 10%, long-term durability, and scalability.
A high-efficiency wireless artificial leaf-based solar hydrogen production system. Image credit: UNIST
In a recent study, researchers at Ulsan National Institute of Science and Technology (UNIST) developed 1 cm2 perovskite-based photoelectrodes using a defect-less, chlorine-doped formamidinium lead triiodide as photo-absorber and ultraviolet-insensitive tin oxide as an electron transport layers.
This device is encapsulated using electrocatalyst-deposited nickel foils, which demonstrates high photocurrent density and high stability for 140 h.
Then, the scientists fabricated a scalable mini-module-sized artificial leaf (16 cm2) consisting of a side-by-side/parallel configuration of photoanode and photocathode architecture integrated with a 4 × 4 array of 1 cm2 photoelectrodes, which maintains a stable ‘module-level’ solar-to-hydrogen efficiency of 11.2% in an unbiased solar water-splitting under 1-sun illumination.
Professor Lee Jae-sung noted, "This achievement is significant in that it exceeds merely high-efficiency hydrogen production in the laboratory and has achieved the commercialization benchmark of efficiency over 10% at a usable level for modular artificial photosynthesis devices. Additionally, it can be scaled up to large-area artificial leaf panels like solar panels, making a decisive advance towards commercialization."
