Rational Interfacing of Organic Semiconducting Double‐Cable Polymer and Reduced Graphene Oxide for Enhanced Artificial Photosynthesis of H ₂ O ₂

Double‐cable polymers (DCPs), consisting of covalently conjugated organic semiconducting polymer electron donors (D) and nonfullerene electron acceptors (A), have emerged as promising single‐component D–A photoactive materials. The photoactivities of DCPs are, however, capped by their intrinsic chemical nature. Herein, we demonstrate that the light harvesting and energy conversion capabilities of DCPs can be augmented by interfacing them with functional additives without changing their chemical nature. A DCP consisting of polythiophene (PTh)–perylene diimide (PDI) D–A components is interfaced with the reduced graphene oxide (rGO) as functional additive to produce PTh‐PDI‐DCP/rGO hybrid. Fluorescence spectroscopy, cyclic voltammetry, linear sweep voltammetry, and electrochemical impedance spectroscopy performed as a function of varying wt.% of rGO reveal the charge transfer between the components of PTh‐PDI‐DCP/rGO and suggest that the optimum rGO content in the hybrid is 15 wt.%. As photocatalyst in the artificial photosynthesis of H ₂ O ₂ , the PTh‐PDI‐DCP/rGO hybrid exhibits an H ₂ O ₂ generation rate of 120.8 ± 3.1 µM mg ⁻¹ h ⁻¹ averaged over 10 photocatalytic cycles, which are 3.3, 2.4, 3.5, 1.5, 1.4, and 2.6‐fold enhancements compared to rGO, P3HT, PDI, PTh‐PDI‐DCP, P3HT/rGO, and PDI/rGO, respectively. Overall, this work offers a new avenue to expanding the design space of photoactive materials through strategic interfacing of DCPs with rationally selected functional additives.