In Situ Visualization of Fast Surface Ion Diffusion in Vanadium Dioxide Nanowires
In Situ Visualization of Fast Surface Ion Diffusion in Vanadium Dioxide Nanowires
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DOI：
10.1021/acs.nanolett.7b03832
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发表时间：
2017-12-01
期刊：
影响因子：
10.8
通讯作者：
Yu, Dong
中科院分区：
文献类型：
--
作者：
Hou, Yasen;Xiao, Rui;Yu, Dong
利用光电流成像技术研究了二氧化钒纳米线（NWs）中离子的原位扩散。碱金属离子通过离子液体门控注入NW段，并沿NW轴扩散。离子扩散的可视化是通过空间分辨光电流测量来实现的，该测量可以检测与离子掺入相关的载流子密度变化。在室温下，Li+和Na+离子的扩散常数约为10(-10)cm(2)/s，而H+的扩散速度要慢得多。离子扩散也主要发生在NWs的表面，因为金属接触可以有效地阻止离子扩散。这种可视化离子分布的新方法有望应用于广泛材料中的离子扩散研究，为相变电子学和储能应用提供关键见解。
We investigate in situ ion diffusion in vanadium dioxide (VO2) nanowires (NWs) by using photocurrent imaging. Alkali metal ions are injected into a NW segment via ionic liquid gating and are shown to diffuse along the NW axis. The visualization of ion diffusion is realized by spatially resolved photocurrent measurements, which detect the charge carrier density change associated with the ion incorporation. Diffusion constants are determined to be on the order of 10(-10) cm(2)/s for both Li+ and Na+ ions at room temperature, while H+ diffuses much slower. The ion diffusion is also found to occur mainly at the surface of the NWs, as metal contacts can effectively block the ion diffusion. This novel method of visualizing ion distribution is expected to be applied to study ion diffusion in a broad range of materials, providing key insights on phase transition electronics and energy storage applications.