End Group‐Induced Ultrafast Exciton Dissociation of Supramolecular Perylene Monoimide Nanoribbons for Efficient Photocatalytic Hydrogen Evolution

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Abstract Achieving fast exciton dissociation is a critical factor for optimizing the performance of organic photocatalysts in solar energy conversion. This work demonstrates the end‐group‐dependent ultrafast exciton dissociation in supramolecular perylene monoimide (PMI) nanostructures. A series of PMI molecules are designed by connecting the amide site with methylene carboxyl (─CH2─COOH), methylene phosphonic acid (─CH2─PO3H2), and methylene sulfonic acid (─CH2─SO3H) to increase the dipole moment and built‐in electric field, thereby effectively diminishing exciton binding energy. Upon photoexcitation, self‐assembled PMI‐CH2‐SO3H nanoribbons (NRs), which exhibit the lowest exciton binding energy of 29.4 meV, achieve ultrafast exciton dissociation within 0.25 ps, leading to the formation of charge‐separated excitons from charge‐transfer states. This dissociation rate is ≈40 and 16 times faster than that observed in PMI‐CH2‐COOH (NRs) and PMI‐CH2‐PO3H2 (NRs), respectively. Following the deposition of Pt nanoparticles on PMI NRs, Pt/PMI‐CH2‐SO3H (NRs) demonstrates an H2 evolution of 21.2 mmol g−1 h−1 under visible light irradiation (λ > 420 nm), outperforming Pt/PMI‐CH2‐COOH (NRs) and Pt/PMI‐CH2‐PO3H2 (NRs) by factors of 53 and 5.4, respectively.

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