Substrate–Electrode Interface Engineering by an Electron-Transport Layer in Hematite Photoanode

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• 作者：Chunmei Ding ; Zhiliang Wang ; Jingying Shi ; Tingting Yao ; Ailong Li ; Pengli Yan ; Baokun Huang ; Can Li
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：March 23, 2016
• 年：2016
• 卷：8
• 期：11
• 页码：7086-7091
• 全文大小：478K
• ISSN：1944-8252

文摘

The photoelectrochemical water oxidation efficiency of photoanodes is largely limited by interfacial charge-transfer processes. Herein, a metal oxide electron-transport layer (ETL) was introduced at the substrate–electrode interface. Hematite photoanodes prepared on Li⁺- or WO₃-modified substrates deliver higher photocurrent. It is inferred that a Li-doped Fe₂O₃ (Li:Fe₂O₃) layer with lower flat band potential than the bulk is formed. Li:Fe₂O₃ and WO₃ are proved to function as an expressway for electron extraction. Via introducing ETL, both the charge separation and injection efficiencies are improved. The lifetime of photogenerated electrons is prolonged by 3 times, and the ratio of surface charge transfer and recombination rate is enhanced by 5 times with Li:Fe₂O₃ and 125 times with WO₃ ETL at 1.23 V versus reversible hydrogen electrode. This result indicates the expedited electron extraction from photoanode to the substrate can suppress not only the recombination at the back contact interface but also those at the surface, which results in higher water oxidation efficiency.