Charge Separation in TiO2/BDD Heterojunction Thin Film for Enhanced Photoelectrochemical Performance

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• 作者：Chiaki Terashima ; Ryota Hishinuma ; Nitish Roy ; Yuki Sugiyama ; Sanjay S. Latthe ; Kazuya Nakata ; Takeshi Kondo ; Makoto Yuasa ; Akira Fujishima
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：January 27, 2016
• 年：2016
• 卷：8
• 期：3
• 页码：1583-1588
• 全文大小：322K
• ISSN：1944-8252

文摘

Semiconductor photocatalysis driven by electron/hole has begun a new era in the field of solar energy conversion and storage. Here we report the fabrication and optimization of TiO₂/BDD p-n heterojunction photoelectrode using p-type boron doped diamond (BDD) and n-type TiO₂ which shows enhanced photoelectrochemical activity. A p-type BDD was first deposited on Si substrate by microwave plasma chemical vapor deposition (MPCVD) method and then n-type TiO₂ was sputter coated on top of BDD grains for different durations. The microstructural studies reveal a uniform disposition of anatase TiO₂ and its thickness can be tuned by varying the sputtering time. The formation of p-n heterojunction was confirmed through I–V measurement. A remarkable rectification property of 63773 at 5 V with very small leakage current indicates achieving a superior, uniform and precise p–n junction at TiO₂ sputtering time of 90 min. This suitably formed p-n heterojunction electrode is found to show 1.6 fold higher photoelectrochemical activity than bare n-type TiO₂ electrode at an applied potential of +1.5 V vs SHE. The enhanced photoelectrochemical performance of this TiO₂/BDD electrode is ascribed to the injection of hole from p-type BDD to n-type TiO₂, which increases carrier separation and thereby enhances the photoelectrochemical performance.