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Xinjian Shi1 Xiaolin Zheng1

1, Stanford University, Stanford, California, United States

Plasmonic metal nanostructures have been extensively studied to improve the performance of
metal oxide photoanodes for photoelectrochemical (PEC) solar water splitting cells. Most of
these studies have focused on the effects of those metal nanostructures on enhancing light
absorption and enabling direct energy transfer via hot electrons. However, several recent
studies have shown that plasmonic metal nanostructures can improve the PEC performance of
metal oxide photoanodes via another mechanism known as plasmon-induced resonant energy
transfer (PIRET). However, this PIRET effect has not been yet tested for the molybdenumdoped
bismuth vanadium oxide (Mo:BiVO4), regarded as one of the best metal oxide
photoanode candidate. Here, we constructed a hybrid Au nanosphere/Mo:BiVO4 photoanode
interwoven in a hexagonal pattern to investigate the PIRET effect on the PEC performance of
Mo:BiVO4. We find that the Au nanosphere array not only increases the light absorption of
the photoanode as expected but also improves both its charge transport and charge transfer
efficiencies via PIRET, confirmed by time-correlated single photon counting and transient
absorption studies. Incorporating the Au nanosphere array increases the photocurrent density
of Mo:BiVO4 by ~ 2.2-fold, thereby outperforming all the
other hybrid Au/metal oxide photoanodes in the literature.

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