Controlled Synthesis of Starburst A-π-D Architectured PDI/NDI Conjugated Polymers for High-Efficiency Photocatalytic Oxygen Evolution

Four types of A-π-D type ternary conjugated polymers (PDI-EDOT, PDI-Ph, NDI-EDOT, NDI-Ph) were constructed using direct arylation of C-H bonds and Suzuki coupling, respectively, by introducing EDOT (strong donor) and benzene ring (weak donor) with differentiated electron donor strengths into the rigid thick ring skeleton of perylene/naphthalene, to realize the regulation of intramolecular charge transfer channels. The chemical structure and microscopic morphology of the polymers were analyzed by FT-IR and SEM. Energy band positions were determined by combining UV-Vis DRS with cyclic voltammetry (CV). The photoelectric properties, carrier complex behavior, and charge distribution of the polymers were evaluated by electrochemical tests and DFT calculations. The results of photocatalytic tests showed that PDI-Ph exhibited the most excellent photocatalytic oxygen production performance in the H2O/NMP/AgNO3 reaction system, reaching 4.3 mmol g−1h−1 OER under full-spectrum irradiation, which was 2.2 and 10.2 times higher than that of PDI-EDOT and NDI-Ph, respectively. Photocatalytic cycling tests and infrared spectroscopy demonstrated the better stability of PDI-Ph. This work provides a new idea for the development of efficient and stable organic photocatalytic systems by precisely regulating D-A interactions at the molecular scale.