Dipole‐Manipulated Built‐In Electric Field Enables Ultrafast Charge Separation in Perylene Diimide Polymers for Photoelectrochemical Water Splitting

at 1.23 V vs. RHE), outperforming its counterparts by 3.42-229 times. Ultrafast spectroscopy reveals this enhancement originates from sub-picosecond charge separation and efficient multi-electron accumulation, while theoretical modeling confirms the critical role of linker polarity in BIEF amplification. This work establishes a fundamental structure-kinetics relationship for designing high-performance organic photoelectrodes, providing a versatile strategy for advancing solar energy conversion technologies.