In a significant development for the renewable energy sector, UNIST researchers in Ulsan, South Korea, have unveiled a groundbreaking modular artificial leaf for green hydrogen production. This innovative technology mimics natural photosynthesis to directly convert sunlight and water into hydrogen, eliminating the need for external electricity or contributing to carbon emissions. Unlike traditional solar panel-electrolysis systems, the artificial leaf streamlines the process by converting sunlight into chemical energy without an intermediate electrical conversion step. The research team, led by Professors Jae Sung Lee, Sang Il Seok, and Ji Wook Jang, overcame efficiency, durability, and scalability challenges by introducing a perovskite-based photoelectrode with nickel-iron-cobalt catalysts. This breakthrough resulted in a 4x4 array system achieving a record 11.2% solar-to-hydrogen conversion efficiency, marking a significant advancement in green energy technology. The success of the artificial leaf lies in its material science innovations, including a chlorine-doped perovskite absorber for enhanced light capture and UV-resistant layers for long-term stability. Notably, the modules demonstrated impressive durability, maintaining 99% of their performance after 140 hours of continuous operation under sunlight and moisture. The scalability of the modular leaf system into large panels, akin to traditional solar arrays, presents a practical pathway for widespread deployment in the global hydrogen economy. This achievement, published in Nature Communications, was made possible through funding from Korea's Ministry of Science and ICT and the Institute for Basic Science, highlighting a collaborative effort to advance clean energy solutions. As nations and industries seek sustainable alternatives to carbon-intensive fuels, UNIST's artificial leaf emerges as a promising player in driving the transition towards a greener future.