Directly Probing Charge Separation at Interface of TiO2 Phase Junction
Directly Probing Charge Separation at Interface of TiO2 Phase Junction
复制标题
直接探测 TiO2 相结界面处的电荷分离
DOI：
10.1021/acs.jpclett.7b00285
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发表时间：
2017-04-06
影响因子：
5.7
通讯作者：
Li, Can
中科院分区：
文献类型：
--
作者：
Gao, Yuying;Zhu, Dian;Li, Can
相结通常被认为是实现电荷有效分离的有效策略。作为决定光生电荷动力学的一个重要因素，相位结界面上的能带排列问题引起了越来越多的争论。在此，我们报告了直接测量的表面电位分布的界面上的TiO 2相结。开尔文探针力显微镜（KPFM）检测到的内置电场高达1 kV/cm的金红石纳米粒子。自制的空间分辨表面光电压谱（SRSPS）为光生电子从金红石向金红石的矢量电荷转移提供了直接证据。此外，在TiO 2相结中可调的纳米颗粒尺寸通过产生完全耗尽的空间电荷区（SCR）和提高电荷分离效率而导致高的表面光电压（SPV）。研究结果为理解内建电场对人工光催化剂界面电荷转移的影响提供了有力的依据。
Phase junction is often recognized as an effective strategy to achieve efficient charge separation in photocatalysis and photochemistry. As a crucial factor to determine the photogenerated charges dynamics, there is an increasingly hot debate about the energy band alignment across the interface of phase junction. Herein, we reported the direct measurement of the surface potential profile over the interface of TiO2 phase junction. A built-in electric field up to 1 kV/cm from rutile to anatase nanoparticle was detected by Kelvin Probe Force Microscopy (KPFM). Home-built spatially resolved surface photovoltage spectroscopy (SRSPS) supplies a direct evidence for the vectorial charge transfer of photogenerated electrons from rutile to anatase. Moreover, the tunable anatase nanoparticle sizes in TiO2 phase junction leads to high surface photovoltage (SPV) by creating completely depleted space charge region (SCR) and enhancing the charge separation efficiency. The results provide a strong basis for understanding the impact of built-in electric field on the charge transfer across the interface of artificial photocatalysts.