Multilayer oxide protection layer with multiple tunnelling paths for efficient and durable Si-based photocathode.

Zhou, Yang; Cheng, Zijie; Lyu, Yanhong; Wang, Jinbo; Tsud, Nataliya; Kalinovych, Viacheslav; De Marco, Roland; Luo, Xiao et al. · Nat Commun · 2026

basic_science · Level V

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Abstract

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)<sub>n</sub>, 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 (TiO<sub>2</sub>/Fe)<sub>n</sub>, (CeO<sub>2</sub>/Fe)<sub>n</sub> and (TiO<sub>2</sub>/Pd)<sub>n</sub>. 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.