Simultaneously suppressing non-radiative and radiative recombination of linear conjugated polymer photocatalysts for boosting visible/near-infrared light photocatalytic hydrogen production

Non-radiative and radiative recombination jointly determine the photogenerated-carrier separation efficiency of photocatalysts. However, linear conjugated polymer photocatalysts (LCPP) still suffer from serious non-radiative recombination caused by exciton-phonon coupling and radiative recombination originating from exciton radiative transition. Herein, we report a strategy to simultaneously suppress non-radiative and radiative recombination in LCPP, which successfully addresses this drawback. Firstly, we successfully synthesized 2D Poly(4,7-dithienyl-2,1,3-benzothiadiazole) (PDTBT) with N…S intramolecular conformational locks to suppress non-radiative recombination. The obtained PDTBT exhibits largely expanded absorption range and efficiently suppressed exciton–phonon coupling. Subsequently, we constructed 2D/2D PDTBT/graphitic carbon nitride (CN) polymer heterojunctions to suppress radiative recombination, and the obtained 25PDTBT/CN exhibits hydrogen production activity up to 17.09 mmol h −1 g −1 with the apparent quantum yields ( AQYs ) of 13.65 % at 700 nm and 4.36 % at 750 nm. The excellent photocatalytic activities are proved to originate from the effectively suppressed exciton-phonon coupling by N…S intramolecular conformational locks and the efficient photogenerated-carrier transfer via van der Waals forces between PDTBT and CN. This research offers a practical approach for suppressing non-radiative and radiative recombination of linear conjugated polymer and constructing efficient 2D/2D polymer heterojunctions.