Aggregation Triggers Red/Near-Infrared Light Hydrogen Production of Organic Dyes with High Efficiency

Integrating broad-band red/near-infrared (NIR) light harvesting and efficient charge separation in a semiconductor is a crucial prerequisite for the realization of high photocatalytic efficiency but remains a challenge. Here, we discover that eosin Y (EY) aggregates exhibit strong red/NIR-light harvesting induced by electronic couplings between adjacent EY molecules. Simultaneously, the aggregates are favorable for exciton dissociation and formation of charge-separation states, greatly inhibiting charge recombination. The quantum yield (QY) of EY aggregates for hydrogen production highly reaches 23.6% at 610 nm. More importantly, this general concept of aggregation-induced red/NIR-light photocatalysis was observed in a series of typical organic dyes (11 examples). Impressively, the QY of cobalt phthalocyanin aggregates for hydrogen production is calculated to be 17.2% at 800 nm, which is the highest value among NIR-light-driven H2-evolution systems (≥800 nm) ever reported. This study unlocks a fresh realm of artificial photosynthesis, which uses dye aggregates for red/NIR-light solar conversion.