Deuteration Induced Electron-Phonon Coupling Modulation: Suppressing Energy Dissipation and Enhancing Carrier...

The electron-phonon coupling in organic photocatalysts offers a great opportunity for tuning carrier behaviors and energy dissipation toward improving photocatalytic efficiency. Adopting strategies to tailor electron-phonon coupling and revealing the underlying mechanism are therefore essential for the development of high-efficiency organic photocatalysts. In this work, an isotope substitution strategy is developed by replacing H in high-frequency C─H oscillators with D to tune the electron-phonon coupling strength of both 1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene (4CzIPN) and its polymeric derivative. The fitted Huang-Rhys factors exhibit an ≈1.7-fold increase upon isotopic deuteration, revealing enhanced electron-phonon coupling. Comprehensive studies demonstrate that the deuteration strategy can effectively lower exciton binding energy, promote exciton dissociation, and suppress non-radiative energy dissipation, therefore leading to an improved efficiency toward photocatalytic hydrogen evolution. This study highlights the crucial role of electron-phonon coupling on photocatalytic systems and presents a novel regulatory strategy for designing high-efficiency organic photocatalysts.