Simultaneous Enhancement of Charge Separation and Hole Transportation in a TiO2–SrTiO3 Core–Shell Nanowire Photoelectrochemical System |
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| Authors: | Fei Wu Yanhao Yu Huang Yang Lazarus N. German Zhenquan Li Jianguo Chen Weiguang Yang Lu Huang Weimin Shi Linjun Wang Xudong Wang |
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| Affiliation: | 1. Department of Electronic Information Materials, School of Materials Science and Engineering, Shanghai University, Shanghai, China;2. Materials Science and Engineering, University of Wisconsin‐Madison, Madison, WI, USA |
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| Abstract: | Efficient charge separation and transportation are key factors that determine the photoelectrochemical (PEC) water‐splitting efficiency. Here, a simultaneous enhancement of charge separation and hole transportation on the basis of ferroelectric polarization in TiO2–SrTiO3 core–shell nanowires (NWs) is reported. The SrTiO3 shell with controllable thicknesses generates a considerable spontaneous polarization, which effectively tunes the electrical band bending of TiO2. Combined with its intrinsically high charge mobility, the ferroelectric SrTiO3 thin shell significantly improves the charge‐separation efficiency (ηseparation) with minimized influence on the hole‐migration property of TiO2 photoelectrodes, leading to a drastically increased photocurrent density ( J ph). Specifically, the 10 nm‐thick SrTiO3 shell yields the highest J ph and ηseparation of 1.43 mA cm?2 and 87.7% at 1.23 V versus reversible hydrogen electrode, respectively, corresponding to 83% and 79% improvements compared with those of pristine TiO2 NWs. The PEC performance can be further manipulated by thermal treatment, and the control of SrTiO3 film thicknesses and electric poling directions. This work suggests a material with combined ferroelectric and semiconducting features could be a promising solution for advancing PEC systems by concurrently promoting the charge‐separation and hole‐transportation properties. |
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| Keywords: | ferroelectric polarization piezotronics photoelectrochemical water splitting SrTiO3 TiO2 nanowires |
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