Aggregation-Induced Synergy in Photocatalysis: Enhanced Light Harvesting and Efficient Charge Separation

The aggregated photocatalytic system has garnered significant attention as a novel platform for addressing contemporary environmental and energy challenges. These systems are typically assembled via weak noncovalent interactions-such as hydrogen bonding, van der Waals forces, and π-π stacking-among metal complexes, organic molecules, and polymers. In contrast to materials constructed with strong covalent or coordination bonds, the weak forces in these aggregates can readily alter their structural organization. This leads to distinct photophysical and chemical properties that differ markedly from their monomeric counterparts, ultimately influencing photocatalytic performance. Nevertheless, systematic understanding of aggregate photocatalysis remains limited, particularly regarding the fundamental mechanisms behind activity enhancement and the inherent constraints of this approach. This review systematically examines our group's research across three key areas: (1) the governing interactions within aggregates; (2) design strategies to improve their photocatalytic efficiency; and (3) representative applications in hydrogen evolution and CO₂ reduction. Furthermore, we identify critical challenges and propose promising future research directions, with the aim of accelerating the development of this rapidly evolving field.