Nanoscale Chemical Reaction Imaging at the Solid-Liquid Interface via TERS
Nanoscale Chemical Reaction Imaging at the Solid-Liquid Interface via TERS
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DOI：
10.1021/acs.jpclett.9b00935
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发表时间：
2019-06-06
影响因子：
5.7
通讯作者：
El-Khoury, Patrick Z.
中科院分区：
文献类型：
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作者：
Bhattarai, Ashish;El-Khoury, Patrick Z.
并非所有光场纳米定位和增强区域都是等离激元金属化学转化的合适位点。我们使用镀金尖端增强拉曼散射 (TERS) 探针对水溶液中的化学功能化单晶金片进行成像来说明这一概念。在我们的原理验证研究中，我们选择了一种等离子体驱动的化学过程模型，即对硝基苯硫酚 (NTP) 二聚为二巯基偶氮苯。与我们小组最近的观察结果一致，我们发现 TERS 映射到与 NTP 对应的振动共振，追踪光场，该光场朝着血小板边缘最大程度增强。相反，同时记录的产物图谱表明二聚过程仅发生在我们的底物上的特定位点。考虑到金片边缘的结构和局部光场的均匀性，我们的结果表明分子拥挤和空间效应在我们的金-水界面等离子体驱动的 NTP 二聚化案例中起着关键作用。
Not all regions of optical field nanolocalization and enhancement are suitable sites for chemical transformations on plasmonic metals. We illustrate the concept using chemically functionalized monocrystalline gold platelets in aqueous solution imaged using a Au-coated tip-enhanced Raman scattering (TERS) probe. For our proof-of-principle study, we select a model plasmon-driven chemical process, namely, the dimerization of p-nitrothiophenol (NTP) to dimercaptoazobenzene. Consistent with recent observations from our group, we find that TERS maps at vibrational resonances corresponding to NTP trace the optical fields that are maximally enhanced toward the edges of the platelets. Conversely, simultaneously recorded product maps reveal that the dimerization process occurs only at specific sites on our substrate. Given the uniformity of the structures and local optical fields at the edges of the gold platelets, our results suggest that molecular crowding and steric effects play a key role in our case of plasmon-driven NTP dimerization at the gold-water interface.