Linear zigzag covalent organic frameworks diminish thermal relaxation and exciton dissociation energy in...

Two-dimensional/three-dimensional imine-based covalent organic frameworks (2D/3D imine-based COFs) face dual bottlenecks in photoelectrochemical (PEC) applications from both intrinsic limitations in charge transport caused by polarized imine bonds and extrinsic barriers to solution-based fabrication of devices. Herein, we overcome both challenges through the dimension-induced carrier optimization strategy by engineering a solution-processable, highly crystalline one-dimensional (1D) zigzag porous COF (1D-COF_CDBA). Its structure inherently bypasses the fundamental electronic constraints while enabling scalable thin-film fabrication. The dual-chain interlocking architecture of the 1D-COF_CDBA suppresses molecular vibration and rotation, resulting in a lower exciton binding energy (37.2 meV) compared to the 2D counterpart (41.0 meV). 1D-COF_CDBA provides an ultralow in-plane electron effective mass for directional charge transport. Consequently, the 1D-ECOF_CDBA photocathode achieves a photocurrent density 1.8 times higher than that of the 2D-ECOF_BCTB at 0.4 V vs. RHE. The solution-processable 1D-ECOF_CDBA nanorods enable direct fabrication of panel photoelectrodes via spin-coating, enabling the realization of high-integrity P3HT/1D-ECOF_CDBA-C₆₀/TiO₂ heterojunction photoelectrodes. This architecture demonstrates a remarkable photocurrent density difference of 147 μA cm^-2 between illuminated and dark conditions at 0.4 V vs. RHE. By implementing dimensionality engineering, this work successfully decouples the processability‒charge dynamics trade-off, paving the way for high-performance organic semiconductors in energy applications.