Dynamic physicochemical nanoscale imaging at the solid-liquid interface

固液界面动态物理化学纳米级成像

• 批准号: EP/V053884/1
• 负责人: Mike George
• 金额: $ 149.3万
• 依托单位: University of Nottingham
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FV053884%2F1
• 关键词: Dynamic; physicochemical; nanoscale; imaging; solid

Raman spectroscopy is an invaluable analytical tool for materials characterisation, providing essential information on the structure, chemical composition and local environment of molecules using the diagnostic fingerprint that the vibrational spectrum uniquely delivers. It is applied almost ubiquitously across the engineering, physical and life sciences, enabling analysis of molecular materials in their native state (regardless of the physical state of matter or environment), in the absence of labels or preparation procedures, in a non-invasive and non-destructive fashion. It does, however, suffer from two significant limitations: (i) low sensitivity, a result of the weakness of the Raman effect, where very few incident photons can be harnessed to generate information on vibrational structure, and; (ii) spatial resolution limited by the laws of optical diffraction. This places fundamental restrictions on the breadth of materials that can be examined, and the absolute precision with which information can be obtained in those that can. Necessitated by the comprehension that the principle functions of materials are governed by characteristics and phenomena that arise in molecular structures at the nanoscale, significant developments in the technology of Raman spectroscopy was warranted and an innovative approach - termed tip-enhanced Raman spectroscopy (TERS) - was consequently established. In TERS, a scanning probe microscopy (SPM) tip is illuminated with a laser at the natural plasmon frequency of the noble metal nanoparticle that resides at the tip apex. This creates a high-intensity electromagnetic field in the immediate vicinity of the SPM tip, and as such provides a new mechanism for high-sensitivity imaging of molecular materials at the nanometre length scale. Yet, to date, and for reasons of prior technical inadequacies of commercial instrumentation, its application has been largely restricted to analysis of solid surfaces in air at standard conditions of temperature and pressure. Thus, whilst TERS has effectively solved the fundamental deficiencies inherent to Raman spectroscopy, it has essentially failed to translate the highly desirable aspects of the parent technique, thus placing a significant barrier to its application for important materials science discoveries. To address this critical issue, we aim to pioneer an innovative nanoscale imaging capability, comprising optically-coupled SPM and Raman spectroscopy, and uniquely configured for the first time with dual optical access, multiple SPM functionalities and custom-made stages and liquid cells for environmental control. Designated DCI-TERS, our cutting-edge analytical platform will enable chemical fingerprint imaging of molecular materials significantly below the diffraction limit (<10 nm spatial resolution) for sampling both liquids and solids, with near-single-molecule-level sensitivity, along with 3D topographical analysis, acquired simultaneously from a single location (Tip-Enhanced Raman Spectroscopy). The incorporation of full performance SPM modes extends the breadth of surface physical characteristics obtainable from a single nanoscale volume (Correlative Imaging), whilst first-time provisions for environmental control stands to revolutionise in situ and operando investigations of chemical transformations at the gas-solid and liquid-solid interfaces, in response to light, heat and electrical potential (Dynamic Imaging). Thus, DCI-TERS represents an innovative methodology for temporally-resolved and location-correlated imaging of molecular materials and will deliver new fundamental knowledge on surface physicochemical (mechanical, electrical, thermal, structural compositional) properties under relevant conditions and at the nanoscale level, applicable to a broad spectrum of material research programmes, from drug delivery and medical devices to optoelectronics and batteries.

拉曼光谱法是用于材料表征的宝贵分析工具，使用诊断指纹提供了有关分子的结构，化学成分和局部环境的重要信息，该指纹振动频谱独特提供。它几乎普遍存在在工程，物理和生命科学中，在没有标签或制备程序的情况下，以非侵入性和无毁灭性的方式对分子材料（无论物质或环境的物理状态如何）进行分析。但是，它确实遭受了两个重要的局限性：（i）低灵敏度，是拉曼效应的弱点的结果，在这种情况下，很少有入射光子可以利用以生成有关振动结构的信息，并且； （ii）由光学衍射定律有限的空间分辨率。这对可以检查的材料的广度进行了基本限制，以及可以在其中可以获得信息的绝对精度。理解材料的原理功能受到纳米级分子结构中产生的特征和现象的理解所需要的，因此确定了拉曼光谱技术的重大发展，并建立了一种创新的方法，称为创新的方法 - 增强的拉曼光谱（TERS）。在TERS中，扫描探针显微镜（SPM）尖端在位于尖端顶点的贵金属纳米颗粒的天然等离子频率处用激光照亮。这在SPM尖端的附近创建了高强度的电磁场，因此为在纳米长度尺度上对分子材料进行高敏性成像的新机制提供了新的机制。然而，迄今为止，出于事先技术不足的商业仪器的原因，其应用很大程度上仅限于在标准的温度和压力条件下对空气中的固体表面的分析。因此，尽管TERS有效地解决了拉曼光谱固有的基本缺陷，但它基本上未能转化父级技术的高度理想方面，从而为其在重要材料科学发现的应用中带来了重大障碍。为了解决这个关键问题，我们的目标是先驱创新的纳米级成像能力，包括光学耦合的SPM和拉曼光谱，并首次使用双重光学访问，多个SPM功能，定制阶段以及以环境控制的液体阶段和液体单元格进行了唯一配置。指定的dciTer，我们的尖端分析平台将使分子材料的化学指纹成像显着低于衍射极限（<10 nm的空间分辨率），用于对液体和固体进行取样，并具有近距离分子级别的敏感性，并从单个位置分析（同时获得tip raman）。完整性能SPM模式的结合扩展了可从单个纳米级体积（相关成像）获得的表面物理特性的广度，而环境控制的首次准备就绪构成了对气体 - 固体和液体固体接口的原位和操作的化学转化调查，以响应光，热量和电势（动力学）。因此，dci-ters代表了一种创新的方法，用于分子材料的时间分辨和与位置相关的成像，并将在相关条件下以及适用于材料研究和医学研究的纳米级，在相关条件下以及适用于纳米级的纳米级，在相关条件下以及在纳米级中提供有关表面物理化学（机械，电气，热，热，结构组成）特性的新基本知识。