Organic solar device sets record for hydrogen production from water

A team at UNIST in South Korea built a tandem organic photocathode that splits water using only sunlight, reaching 7.9% solar-to-hydrogen efficiency without external bias — a record for organic devices. Replacing acidic PEDOT:PSS with a molybdenum oxide and 2PACz layer kept 86% of photocurrent after 10 hours of operation.

• Solar-to-hydrogen efficiency of 7.9% with no applied electrical bias
• Retained 86% of initial photocurrent after 10 hours, versus 36% for conventional designs
• A 320 cm² outdoor module produced hydrogen under natural sunlight
• Platinum cut to 0.1% by weight; modeled hydrogen cost of $4.26 per kilogram