Advances in Organic Semiconductors for Solar-Driven Hydrogen Generation from Water

Organic semiconductors offer a uniquely versatile and cost-effective platform for solar-driven hydrogen generation from water by leveraging scalable and earth-abundant material design. Their high degree of tunability in molecular, optical, and electronic structures has enabled drastic improvements in solar absorptivity, energy level alignment with redox potentials of hydrogen evolution, longer photogenerated charge carrier lifetimes, and improved overall kinetics. This review focuses on the photocatalytic hydrogen generation from water, highlighting the key challenges that continue to limit performance and practical implementation. In particular, we examine recent strategies to address insufficient light absorption, inefficient charge carrier separation, and poor long-term stability across a broad range of organic semiconductor platforms, including conjugated polymers, covalent organic frameworks, and supramolecular assemblies. Finally, we provide an outlook on underexplored opportunities in both reaction kinetics and material design, providing approaches to overcome these persistent limitations and advance organic-semiconductor-based photocatalytic systems.