Constructing a low-resistance oxide protection layer is challenging but highly beneficial for realizing a practical photoelectrochemical device. The thickness of oxide layer strongly influences its behaviors of carrier transport and corrosion resistance, generally leading to a trade-off between efficiency and durability. Different from the previous methods, here we propose and demonstrate a universal approach to decouple the trade-off of oxide layer by multiple carrier-tunnelling paths. This approach with oxide/metal architecture ((O/M)n, n is the number of nano-scale repeating unit) enables low-resistance carrier transport as required for high efficiency, while allowing the layer to be sufficiently thick, which reinforces durability. This approach can be applied to various oxide-based layers, such as (TiO2/Fe)n, (CeO2/Fe)n and (TiO2/Pd)n. In addition, a good correlation between carrier dynamics and oxide/metal architecture is established by employing systematic photoelectrochemical-electrical measurements and simulation models. Here we show important contributions for further developing the practical photoelectrodes in photoelectrochemical devices and controlling the carrier transport behaviors in complex multilayer structure.
Zhou et al. (Sat,) studied this question.