Quantum superlattices offer new path for clean hydrogen from sunlight

Researchers at the University of Michigan have developed excitonic quantum superlattices—ultra-thin layered structures of gallium nitride and indium gallium nitride—that significantly improve the efficiency of photocatalytic water splitting for clean hydrogen production using only sunlight and water. This approach addresses the longstanding inefficiency of photocatalysts in converting solar energy to hydrogen fuel, which emits only water vapor when burned and holds promise for decarbonizing heavy-duty transportation and industrial energy use. The team’s materials demonstrated a solar-to-hydrogen efficiency of 3.16% under concentrated sunlight in lab conditions and 1.64% in outdoor scale-up tests, marking a notable advancement though still below commercial viability thresholds. The key innovation lies in leveraging the quantum-confined Stark effect to extend the lifetime of photogenerated indirect excitons, enhancing charge carrier utilization during water splitting. This breakthrough highlights the potential of quantum superlattices to overcome fundamental limitations in photocatalytic systems and paves the way