Advances in organic semiconductors for photocatalytic hydrogen evolution reaction

Using semiconductor materials for solar-driven hydrogen production is a sustainable alternative to fossil fuels. Organic photocatalysts, composed of elements abundantly available on earth, offer the advantage over their inorganic counterparts due to their capacity for electronic property modulation through molecular engineering. However, our understanding of the critical properties of their photocatalytic redox processes has yet to keep pace, hindering further development toward a cost-competitive technology. Here, we expound upon our present comprehension of the microscopic mechanisms underlying organic semiconductor photocatalysis. This article provides an overview of the current state of organic photocatalyst hydrogen evolution reaction (HER), beginning with a description of the charge transfer model of organic semiconductors. We then analyze the excitonic behavior after photoexcitation and present various control strategies aimed at enhancing the efficiency of organic semiconductor photocatalytic hydrogen production. Additionally, we summarize the research progress of conjugated supramolecular and polymeric organic photocatalysts. Finally, we evaluate the efficiency and stability of organic photocatalyst HER.