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 NIRlight-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.

Automated summary

This study discovered that eosin Y (EY) aggregates have strong red/near-infrared (NIR) light absorption due to electronic couplings between adjacent molecules. The aggregates also facilitate exciton dissociation and charge separation, effectively suppressing charge recombination. The quantum yield of hydrogen production by EY aggregates reaches 23.6% at 610 nm. Furthermore, this aggregation-induced red/NIR-light photocatalysis phenomenon was observed in a series of organic dyes. Notably, the quantum yield of cobalt phthalocyanin aggregates for hydrogen production is calculated to be 17.2% at 800 nm, the highest value reported for NIR-light-driven H2-evolution systems (>= 800 nm).