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Crystalline TiO2 protective layer with graded oxygen defects for efficient and stable silicon-based photocathode.

Jianyun ZhengYanhong LyuRuilun WangChao XieHuaijuan ZhouSan Ping JiangShuangyin Wang
Published in: Nature communications (2018)
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 TiO2 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 TiO2 shows a limiting current density of ~35.3 mA cm-2 and durability of over 100 h at 10 mA cm-2 in 1.0 M NaOH electrolyte, while none of photoelectrochemical behavior is observed in crystalline TiO2 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.
Keyphrases
  • quantum dots
  • visible light
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  • high density
  • room temperature
  • high efficiency
  • sensitive detection