Quinonoid π-Conjugated Interfaces Drive Exciton Dissociation for CO2 Photoreduction on Perovskite Nanocrystals

Halide perovskite nanocrystals are promising photocatalysts for CO 2 reduction due to their strong light absorption, defect tolerance, and tunable excited-state properties, but their practical performance remains limited by tightly bound excitons, rapid charge recombination, and inefficient interfacial electron delivery. Here, we report an anthraquinone (AQ)-modified CsPbBr 3 nanocrystal photocatalyst (CPB/AQ) in which the redox-active π-conjugated AQ ligand functions as an interfacial electron relay and molecular electric-field modulator. Experimental and theoretical analyses collectively reveal that AQ creates an additional interfacial charge-transfer pathway, strengthens the light-induced surface potential difference from 170 to 270 mV, and decreases the exciton binding energy from 44.05 to 40.74 meV. Consequently, CPB/AQ achieves a CO yield of 433.50 μmol g –1 within 3 h under AM 1.5G irradiation, 4.54 times that of pristine CPB, and maintains stable CO evolution during a 25 h test. Isotopic 13 CO 2 tracing verifies that CO originates from CO 2 reduction, while in situ FTIR spectroscopy demonstrates enhanced CO 2 adsorption/activation and accelerated formation of *COOH and *CO intermediates on CPB/AQ. This work highlights molecularly gated interfacial electric-field regulation as an effective strategy for overcoming charge-transfer bottlenecks in perovskite nanocrystal photocatalysis.