Plasmon-Driven Chemistry as Revealed by Ultrafast SERS, Single Molecule SERS, and Electrochemical TERS

在化学系化学测量和成像项目的支持下，西北大学的Van Duyne教授正在进行研究，以更好地了解分子在附近等离子体纳米粒子诱导的强电磁场（EM）存在下的行为和化学反应。表面等离子体激元是电子在等离子体纳米粒子表面集体振荡产生的一种现象。许多因素影响电磁场（即等离子体场）的强度以及分子的密切行为。Van Duyne教授计划研究等离子体驱动化学的基本机制，使用一种称为表面增强拉曼光谱（SM-SERS）的技术研究对单分子的化学增强贡献，并开发电化学尖端增强拉曼光谱（EC-TERS）来询问化学反应过程中电荷如何在界面上转移。从他的研究中获得的基本见解可以实现包括光催化、电催化、能量转换在内的新技术应用，并在生物传感、国防和医疗保健等多个领域推进广泛的技术。Van Duyne教授在他的研究小组中与他的研究生和博士后密切合作，其中许多是女学生。他还计划在夏季接待高中教师，并在校园的“所有童子军纳米日”上与孩子们和他们的父母互动，继续他的公众推广工作。应用表面增强飞秒受激拉曼光谱（SE-FSRS）获得多时间尺度上的反应机理信息。为了将单分子表面增强拉曼光谱推广到小分子，研究了化学增强的贡献，以提供额外的信号增强来提高SMSERS的灵敏度。Van Duyne教授计划开发电化学尖端增强拉曼光谱（EC-TERS）来阐明非均质电荷转移反应的机制。EC-TERS可以提供精确到单位点的空间分辨率的化学信息。通过本文的研究，预计等离子体在纳米和分子尺度上的基本理解和新应用将得到推进。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Chemical Measurement and Imaging Program in the Division of Chemistry, Professor Van Duyne at Northwestern University is conducting studies to better understand how molecules behave and chemical reactions happen in the presence of a strong electromagnetic (EM) field induced by nearby plasmonic nanoparticles. Surface plasmon is a phenomenon from the oscillation of electrons on the surface of plasmonic nanoparticles collectively. Many factors affect how strong the EM field (i.e. the plasmonic field) is and how a molecule closely behaves. Professor Van Duyne plans to investigate the fundamental mechanisms of plasmon-driven chemistry, study the chemical enhancement contribution to single-molecule using a technique called surface-enhanced Raman spectroscopy (SM-SERS), and develop an electrochemical tip-enhanced Raman spectroscopy (EC-TERS) to interrogate how charge transfer across interfaces during chemical reactions. Fundamental insight gained from his study could enable new technological applications including photocatalysis, electrocatalysis, energy conversion and advance a wide array of technologies in multiple sectors including biosensing, defense, and healthcare. Professor Van Duyne works close with his graduate students and postdoctoral fellows, many women students, in his research group. He also plans to continue his outreach efforts to the public by hosting high school teachers in summers and interact with kids and their parents at an All Scout Nano Day on campus. Surface-enhanced femtosecond stimulated Raman spectroscopy (SE-FSRS) is applied to yield reaction mechanistic information across multiple time scales. In order to generalize single molecule surface-enhanced Raman spectroscopy to small molecules, chemical enhancement contribution is investigated to provide additional signal enhancement to boost the sensitivity of SMSERS. Professor Van Duyne plans to develop Electrochemical tip-enhanced Raman spectroscopy (EC-TERS) to elucidate the mechanisms of heterogeneous charge transfer reactions. EC-TERS can provide chemical information with spatial resolution down to the single site limit. Both fundamental understanding and novel applications of plasmonics on the nano and molecular scale is anticipated to be advanced through the proposed research.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.