Defect‐Enhanced Charge Separation and Transfer within Protection Layer/Semiconductor Structure of Photoanodes,Advanced Materials

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Defect‐Enhanced Charge Separation and Transfer within Protection Layer/Semiconductor Structure of Photoanodes
Advanced Materials ( IF 27.4 ) Pub Date : 2018-06-19 , DOI: 10.1002/adma.201801773
Jianyun Zheng ₁ , Yanhong Lyu ₁ , Chao Xie ₁ , Ruilun Wang ₁ , Li Tao ₁ , Haibo Wu ₂ , Huaijuan Zhou ₂ , Sanping Jiang ₃ , Shuangyin Wang ₁

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Silicon (Si) requires a protection layer to maintain stable and long‐time photoanodic reaction. However, poor charge separation and transfer are key constraint factors in protection layer/Si photoanodes that reduce their water‐splitting efficiency. Here, a simultaneous enhancement of charge separation and transfer in Nb‐doped NiO_x/Ni/black‐Si photoanodes induced by plasma treatment is reported. The optimized photoanodes yield the highest charge‐separation efficiency (η_sep) of ≈81% at 1.23 V versus reversible hydrogen electrode, corresponding to the photocurrent density of ≈29.1 mA cm⁻². On the basis of detailed characterizations, the concentration and species of oxygen defects in the NiO_x‐based layer are adjusted by synergistic effect of Nb doping and plasma treatment, which are the dominating factors for forming suitable band structure and providing a favorable hole‐migration channel. This work elucidates the important role of oxygen defects on charge separation and transfer in the protection layer/Si‐based photoelectrochemical systems and is encouraging for application of this synergistic strategy to other candidate photoanodes.

中文翻译：

光电阳极保护层/半导体结构内缺陷增强的电荷分离和转移

硅（Si）需要保护层以维持稳定且长时间的光阳极反应。但是，不良的电荷分离和转移是保护层/ Si光电阳极降低其水分解效率的关键制约因素。在此，据报道，等离子体处理诱导的掺Nb的NiO _x / Ni / black-Si光阳极中电荷分离和转移同时增强。优化的光阳极产生最高的电荷分离效率（η_月的≈81％）在的1.23V相对于可逆氢电极，对应于≈29.1毫安厘米光电流密度^-2。根据详细的表征，NiO _x中氧缺陷的浓度和种类Nb掺杂和等离子体处理的协同作用可调整基层，这是形成合适的能带结构并提供良好的空穴迁移通道的主要因素。这项工作阐明了氧缺陷在保护层/基于硅的光电化学系统中对电荷分离和转移的重要作用，并鼓励将该协同策略应用于其他候选光阳极。

更新日期：2018-06-19

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