Plasmon-Enhanced Scanning Probe Spectroscopy for Chemical Mapping of Nanoscale Interfaces

用于纳米级界面化学测绘的等离子体激元增强扫描探针光谱

• 批准号: 1807891
• 负责人: Andrea Tao
• 金额: $ 40.5万
• 依托单位: University of California-San Diego
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-01 至 2023-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1807891&HistoricalAwards=false
• 关键词: Plasmon; Enhanced; Scanning; Probe; Spectroscopy

With support from the Chemical Measurement and Imaging Program in the Division of Chemistry, Professor Tao at University of California, San Diego, studies and develops new tools for surface analysis. Although surfaces and interfaces play a critical role in dictating key chemical processes, adequate tools for nanoscale surface analysis are lacking. Professor Tao is studying and creating optical probes that are capable of focusing light down to nanoscale volumes (the diameter of a human hair) that could be used in applications such as bioimaging, catalysis, plasmonics, and solid-state surface science. This project provides unique research opportunities for undergraduates, graduates, and high school students to learn about optics and nanomaterials. Professor Tao collaborates with a nanomaterials start-up company, which provides her students with direct and personal insight into the entrepreneur roadmap. Professor Tao is also interested in enhancing the diversity of the engineering community at UC San Diego. This research contributes to chemical industry by ensuring product quality as well as helping to improve synthetic methods by reducing defects. This project integrates atomic force microscopy (AFM) and tip-enhanced Raman spectroscopy (TERS) for carrying out multi-modal measurement of both the chemical and mechanical properties of surfaces and surface binding events. AFM-TERS carries out point-by-point acquisition of chemical information-rich Raman spectra by using a metallic optical antenna to facilitate near-field amplification of both the incident and Raman-scattered light. This work investigates the chemical and physical properties of colloidal AFM-TERS probes that are fabricated by the assembly of shaped metal nanocrystals onto AFM tips. Silver nanocube probes serve as a model system to understand the light-matter interactions that are critical for achieving large Raman enhancements and low background signals. These studies provide new fundamental insight into how near-field optical probes interact with molecular and surface analytes, clarify how near-field optical confinement is supported at the tip-substrate junction, and investigate how the enhancement of other optical processes (e.g. inelastic scattering, multiphoton absorbance) affect TERS readouts. Both experiments and models are used to identify and develop design rules for nanocrystal optical antennas to maximize Raman sensitivities and imaging resolution. The resulting nanocrystal-based AFM-TERS platform are applied toward the chemical and force imaging of nanomaterials and biological surfaces.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.

在化学系化学测量和成像计划的支持下，加州大学圣地亚哥分校的陶教授研究和开发了新的表面分析工具。尽管表面和界面在决定关键的化学过程中起着关键的作用，但缺乏足够的工具来进行纳米尺度的表面分析。陶教授正在研究和创造能够将光聚焦到纳米级体积(人类头发的直径)的光学探测器，这些探测器可以用于生物成像、催化、等离子体和固态表面科学等应用。这个项目为本科生、毕业生和高中生提供了学习光学和纳米材料的独特研究机会。陶教授与一家纳米材料初创公司合作，为她的学生提供对创业路线图的直接和个人见解。陶教授还对提高加州大学圣地亚哥分校工程学社区的多样性感兴趣。这项研究通过确保产品质量和通过减少缺陷来帮助改进合成方法，为化学工业做出了贡献。该项目结合了原子力显微镜(AFM)和尖端增强拉曼光谱(TERS)，对表面的化学和机械性质以及表面结合事件进行了多模式测量。原子力显微镜通过使用金属光学天线逐点获取化学信息丰富的拉曼光谱，以促进入射光和拉曼散射光的近场放大。这项工作研究了胶体AFM探针的化学和物理性质，这种探针是通过将成形的金属纳米晶体组装到AFM尖端而制成的。银纳米立方体探测器作为一个模型系统来理解光-物质相互作用，而光-物质相互作用对于实现大的拉曼增强和低本底信号至关重要。这些研究为近场光学探测器如何与分子和表面分析物相互作用提供了新的基本见解，阐明了近场光学限制如何在尖端-衬底结处得到支持，并研究了其他光学过程(如非弹性散射、多光子吸收)的增强如何影响TERS读数。实验和模型都被用来确定和开发纳米晶体光学天线的设计规则，以最大限度地提高拉曼灵敏度和成像分辨率。由此产生的基于纳米晶体的AFM-TERS平台被应用于纳米材料和生物表面的化学和力成像。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Large optical nonlinearity enabled by coupled metallic quantum wells

• DOI: 10.1038/s41377-019-0123-4
• 发表时间: 2019-01-23
• 期刊: LIGHT-SCIENCE & APPLICATIONS
• 影响因子: 19.4
• 作者: Qian, Haoliang;Li, Shilong;Liu, Zhaowei
• 通讯作者: Liu, Zhaowei