Molecular modulation of fluorene-dibenzothiophene-S,S-dioxide-based conjugated polymers for enhanced photoelectrochemical water oxidation under visible light

Three conjugated polymers (CPs) bearing a common fluorene-dibenzothiophene-S,S-dioxide backbone were designed and synthesized for photoelectrochemical (PEC) water oxidation upon visible-light irradiation (>420 nm). Without the assistance of additional sacrificial agents or co-catalysts, a good photocurrent response of 4.1 μA cm⁻² at +0.6 V (vs. Ag/AgCl) was achieved through facile molecular modulation of the polymer, which improved the uniformity and crystallinity of the film and facilitated charge transport among polymer chains. Moreover, C12 was used for preparation of a composite film with TiO₂ nanorod arrays via spin-coating to yield an approximately 11-fold higher anodic PEC activity than that of pure TiO₂. Our results demonstrated the great potential of solution-processable conjugated polymers for facile construction of highly efficient PEC devices for water splitting.