Crystalline TiO<sub>2</sub> protective layer with graded oxygen defects for efficient and stable silicon-based photocathode.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30177720.
- Also identified by DOI 10.1038/s41467-018-05580-z and PMC identifier 6120862.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The trade-offs between photoelectrode efficiency and stability significantly hinder the practical application of silicon-based photoelectrochemical devices. Here, we report a facile approach to decouple the trade-offs of silicon-based photocathodes by employing crystalline TiO<sub>2</sub> with graded oxygen defects as protection layer. The crystalline protection layer provides high-density structure and enhances stability, and at the same time oxygen defects allow the carrier transport with low resistance as required for high efficiency. The silicon-based photocathode with black TiO<sub>2</sub> shows a limiting current density of ~35.3 mA cm<sup>-2</sup> and durability of over 100 h at 10 mA cm<sup>-2</sup> in 1.0 M NaOH electrolyte, while none of photoelectrochemical behavior is observed in crystalline TiO<sub>2</sub> protection layer. These findings have significant suggestions for further development of silicon-based, III-V compounds and other photoelectrodes and offer the possibility for achieving highly efficient and durable photoelectrochemical devices.