Sub-nanometer Optical Imaging and Self-Assembly on Plasmonic Metals

我的团队的长期目标是利用扫描探针的能力，例如本提案中描述的两个新的最先进的扫描探针显微镜，来解决纳米光子学和表面化学/物理方面的关键研究问题。在本提案中，确定并描述了两个研究问题/主题。通过将扫描隧道显微镜与光谱学相结合，证明了单分子的光致发光和拉曼图像可以在亚纳米级的空间分辨率下获得。这些结果戏剧性地说明了等离子体材料如何增强光学过程，它们也代表了原子光学分辨率的重要一步。与皇后大学的理论学家一起，我们的目标是开发和测试光致发光和尖端增强拉曼成像的光学增强的量子力学模型，包括振动分子和等离子体共振之间的光-机械耦合。我们将使用低温纳米光学显微镜对模型系统进行光学成像，包括分子和原子精确的纳米团簇。使用带有qPlus传感器的非接触式原子力显微镜来选择原子尖。这将对等离子体增强产生根本性的影响，并有可能应用于纳米级光学器件，这是北美一个重要的技术市场。虽然有机分子在金属表面的自组装是纳米尺度上图像化最有效的方法之一，但常用的硫醇基自组装单层的热不稳定性和氧化不稳定性是其在等离子光学器件中广泛商业应用的重大障碍。在化学方面，我们已经证明了N-杂环碳烯（NHCs）是硫醇的可行替代品。我们的目标是通过系统地修改NHCs的结构，同时对其表面化学、自组装方法和协议进行分子水平的理解，来优化这些新覆盖系统的稳定性。影响将是基于NHCs的优化的下一代金属表面功能化剂，可作为表面改性剂，应用于分子电子学，微接触印刷，生物传感和表面保护。通过研究NHC在表面上的自组装获得的见解也将为合成用于医学和催化的NHC稳定金属纳米团簇提供信息。该计划将为18名以下级别的学生提供培训：2名博士，6名硕士，5名本科生暑期学生和5篇最后一年的荣誉论文。

My group's long-term goal is to use the capabilities of scanning probes, such as the two new state-of-the-art scanning probe microscopes described in this proposal, to address critical research questions in nanophotonics and surface chemistry/physics. In this proposal, two research questions/themes are identified and described. Theme 1: Towards atomic optical imaging with quantum optical plasmonics By combining scanning tunnelling microscopy with optical spectroscopy, it has been demonstrated that photoluminescence and also Raman images of single molecules can be acquired with sub--nanometer spatial resolution. These results dramatically illustrate how plasmonic materials can enhance optical processes and they also represent an important step towards atomic optical resolution. With theorists at Queen's, our goal is to develop and test a quantum mechanical model of the optical enhancement in photoluminescence and tip---enhanced Raman imaging that includes the opto-mechanical coupling between the vibrating molecules and the plasmon resonance. We will perform optical imaging of model systems, including molecules and atomically precise nano-clusters, using a cryogenic nano--optical microscope. Atomically sharp tips will be selected using non-contact atomic force microscopy with a qPlus sensor. The impact will be fundamental insights into plasmon enhancement that could potentially have applications for nanoscale optical devices, an important technology market in North America. Theme 2: Self--assembly of N--heterocylic carbenes on plasmonic metals Although the self--assembly of organic molecules on metallic surfaces is one of the most powerful methods for patterning at the nanometer scale, the thermal and oxidative instability of commonly used thiol-based self-assembled monolayers are significant impediments to their widespread commercial use in plasmonic optical devices. With collaborators in Chemistry, we have demonstrated that N--heterocyclic carbenes (NHCs) represent a viable alternative to thiols. Our goal is to optimize the stability of these new overlayer systems by systematically modifying the structure of the NHCs and concurrently developing a molecular--level understanding of their surface chemistry, self--assembly methods and protocols. The impact will be an optimized next generation functionalizing agent for metal surfaces based on NHCs that can be used as a surface modifier with applications in molecular electronics, microcontact printing, biosensing and surface protection. The insights gained through the study of NHC self-assembly on surfaces will also inform the synthesis of NHC-stabilized metal nanoclusters that are used in medicine and catalysis. This proposal will provide training for a total of 18 students at the following levels: 2 PhD, 6 MSc, 5 undergraduate summer students, and 5 final year honours theses.