Photodynamic Controls of Harmful Algal Blooms by an Ultra-efficient and Degradable AIEgen-based Photosensitizer

Harmful algal blooms (HAB) have severe impacts on human health, aquatic ecosystems, and economy. There is still a lack of effective means to control the algal blooms. Herein, a positively charged photosensitizer with aggregation induced emission (AIE) characteristics, namely TVP-A, is reported for its super-efficient, cost-effective, and eco-friendly governance of HAB. TVP-A possesses a characteristically high quantum yield of harvesting white light into reactive oxygen species (ROS). Attributed to its positive charges, TVP-A has good water solubility and can quickly adsorb onto algal cells floating on the water surface. It effectively triggers cell death through oxidative destruction of the nuclei and chloroplasts of algae. The extremely low effective concentration of TVP-A and the short irradiation time by natural light in removing algal blooms ensure its application at large scales under most weather conditions, without affecting other existing organisms. The slow but consistent self-degradation of TVP-A during the photodynamic controls of algal blooms avoids generating any environmental residues or secondary pollution to environmental systems. TVP-A thereby serves as an excellent candidate for the green governance of HAB, and this work represents a new paradigm for the development of efficient and degradable AIEgens for future environmental applications.