Elemental Doping Boosts Charge-Transfer Excitonic States in Polymeric Photocatalysts for Selective Oxidation Reaction
Peng Zhang, Lei Li, Jun Zhao, Hui Wang, Xiaodong Zhang, Yi Xie
Abstract
High Resolution Image Download MS PowerPoint Slide Energy-transfer-mediated synthetic reactions play vital roles in the production of high-value-added organics, where the long-lived exciton harvesting is an essential precondition for the process. However, for semiconductors with strong excitonic effects like conjugated polymers, their predominant Frenkel exciton with a short lifetime in the unified framework gives rise to low efficiency photocatalysis. Herein, we propose the boosting of the charge-transfer exciton with a long-lived state by introducing spatially separated electron and hole regions. By taking polymeric carbon nitride (PCN) as a prototype, we demonstrate that sulfur doping leads to the formation of electron donor and acceptor motifs in the tri-s-triazine-based backbone, which would accommodate long-lived excitonic states with remarkable charge-transfer characteristics. The extraordinary long-lived charge-transfer exciton harvesting endows sulfur-doped PCN with high-efficiency photocatalytic performance in 1 O 2 generation and selective oxidation of organic sulfides. This work provides a brand new perspective for designing advanced photocatalysts for energy-transfer-mediated sunlight utilization.