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Defect‐Enhanced Charge Separation and Transfer within Protection Layer/Semiconductor Structure of Photoanodes
Author(s) -
Zheng Jianyun,
Lyu Yanhong,
Xie Chao,
Wang Ruilun,
Tao Li,
Wu Haibo,
Zhou Huaijuan,
Jiang Sanping,
Wang Shuangyin
Publication year - 2018
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201801773
Subject(s) - materials science , photocurrent , doping , layer (electronics) , semiconductor , water splitting , optoelectronics , electrode , oxygen evolution , plasma , silicon , chemical engineering , nanotechnology , electrochemistry , catalysis , photocatalysis , chemistry , biochemistry , physics , quantum mechanics , engineering
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.