Organic Photovoltaic Catalyst with Extended Exciton Diffusion for High-Performance Solar Hydrogen Evolution

The short exciton diffusion length (L_D) associated with most classical organic photocatalysts (5-10 nm) imposes severe limits on photocatalytic hydrogen evolution efficiency. Here, a photovoltaic molecule (F1) without electron-deficient units at the central building block was designed and synthesized to improve the photoluminescence quantum yield (PLQY). With the enhanced PLQY of 9.3% and a large integral spectral overlap of 3.32 × 10¹⁶ nm⁴ M^-1 cm^-1, the average L_D of F1 film increases to 20 nm, nearly twice the length of the control photovoltaic molecule (Y6). Then, the single-component organic nanoparticles (SC-NPs) based on F1 show an optimized average hydrogen evolution rate (HER) of 152.60 mmol h^-1 g^-1 under AM 1.5G sunlight (100 mW cm^-2) illumination for 10 h, which is among the best results for photocatalytic hydrogen evolution.