Controllably Interfacing with Ferroelectric Layer: A Strategy for Enhancing Water Oxidation on Silicon by Surface Polarization

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• 作者：Wei Cui ; Zhouhui Xia ; Shan Wu ; Fengjiao Chen ; Yanguang Li ; Baoquan Sun
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：November 25, 2015
• 年：2015
• 卷：7
• 期：46
• 页码：25601-25607
• 全文大小：415K
• ISSN：1944-8252

文摘

Silicon (Si) is an important material in photoelectrochemical (PEC) water splitting because of its good light-harvesting capability as well as excellent charge-transport properties. However, the shallow valence band edge of Si hinders its PEC performance for water oxidation. Generally, thanks to their deep valence band edge, metal oxides are incorporated with Si to improve the performance, but they also decrease the transportation of carriers in the electrode. Here, we integrated a ferroelectric poly(vinylidene fluoride鈥搕rifluoroethylene) [P(VDF鈥揟rFE)] layer with Si to increase the photovoltage as well as the saturated current density. Because of the prominent ferroelectric property from P(VDF鈥揟rFE), the Schottky barrier between Si and the electrolyte can be facially tuned by manipulating the poling direction of the ferroelectric domains. The photovoltage is improved from 460 to 540 mV with a forward-poled P(VDF鈥揟rFE) layer, while the current density increased from 5.8 to 12.4 mA/cm² at 1.23 V bias versus reversible hydrogen electrode.