Charge‐Transfer‐Coupled J‐Aggregation Enhances ROS Generation via Efficient Intermolecular Electron Transfer for Photodynamic Therapy

Abstract Aggregation engineering of organic photosensitizers (PSs) is a promising strategy to enhance reactive oxygen species (ROS) production for photodynamic therapy (PDT). However, current approaches primarily rely on traditional long‐range coulomb‐coupled J‐aggregate ( J C ) that exhibit suboptimal Type II ROS production and weak intermolecular electron transfer ( Inter ET), which is unfavorable for Type I ROS generation. Here, we report a charge‐transfer (CT)‐coupled J‐aggregates ( J CT ) as efficient organic PS (BDR NPs) to significantly enhance both Type I and Type II ROS production for superior PDT. Unlike traditional J C ‐aggregates, J CT ‐ aggregates exhibit both accelerated intersystem crossing for improved Type II ROS generation and enlarged intermolecular orbital overlap that promotes efficient Inter ET for Type I ROS production. Therefore, BDR NPs achieve 8.2‐ and 4.1‐fold increases in superoxide (O 2 − •) and hydroxyl radical (•OH) production, respectively, compared with its J C ‐counterparts. Notably, BDR NPs exhibit an over 2‐fold higher production of O 2 − • and •OH compared with commercial PS Rose Bengal, achieving markedly accelerated wound healing. This superior PDT efficacy arises from the synergistic suppression of inflammation and activation of tissue regeneration. This work elucidates the mechanistic basis of J CT ‐ aggregate in enhancing ROS production, offering a foundational framework for designing high‐performance PSs.