Synthesis, structural characterization, and photocatalytic performance of iodine-substituted D-π-A type photosensitizers

The development of efficient photocatalysts for energy conversion and environmental remediation is critical for addressing global challenges in sustainable energy and pollution control. Traditional photocatalytic materials often suffer from limitations such as narrow light absorption ranges, rapid charge recombination, and insufficient stability under harsh conditions. To overcome these issues, this study designed and synthesized a novel iodine-substituted D-π-A type photosensitizer JS, utilizing phenol-modified carbazole as the electron donor and indole salt as the electron acceptor. The D-π-A structure enhances intramolecular charge transfer and extends the conjugation system, resulting in a broadened absorption spectrum with a red shift to 510 nm, enabling efficient utilization of visible light. The incorporation of iodine atoms strengthens spin-orbit coupling, The heavy atom effect of iodine is used to promoting intersystem crossing (ISC) and enhancing the generation of reactive oxygen species (ROS) such as superoxide anion radicals (O₂ •−) and singlet oxygen ( ¹O₂). These ROS play a vital role in photocatalytic processes, including organic pollutant degradation and water splitting. This work provides a structural design strategy for optimizing photosensitizers in photocatalytic applications, offering potential solutions for energy conversion and environmental sustainability.