Transient absorption microscopy studies of the dynamics of single metal and semiconductor nanostructures

Notre Dame大学的Gregory V.哈特兰教授得到化学系大分子、超分子和纳米化学（MSN）项目的支持，研究金属纳米线中的化学反应和电子传导。这些实验的结果对于开发超灵敏的质量传感器和使用光而不是电流来传输信息的电路非常重要。 如果成功，这项创新将使电路和传感器小型化到纳米尺度。研究生和本科生都参加了这项研究。该项目的本科生来自圣母大学，以及北方印第安纳州附近研究设施有限的四年制大学。 本科生和研究生还参与了一系列与南本德地区当地高中生联系的外联活动。正在进行的实验提供了有关纳米材料如何与其环境相互作用的新信息，以及这些相互作用与宏观物体的相互作用如何不同。 正在探索的效应包括表面结合分子在介导纳米材料中的能量弛豫中的作用，简单溶剂（如水）是否在纳米尺度上表现得像粘弹性溶剂，以及环境影响表面等离子体激元（即在纳米线表面传播的电磁波）特性的方式。这些测量是使用瞬态吸收显微镜进行的，这是一种实验技术，可以在单个纳米物体上进行超快激光测量。 作为该项目的一部分，还进行了模拟。 将实验结果与模拟结果进行比较，可以生成有关材料特性的信息，这些信息可供不同科学和工程领域的其他研究人员使用。

Prof. Gregory V. Hartland of the University of Notre Dame is supported by the Macromolecular, Supramolecular, and Nanochemistry (MSN) Program in the Division of Chemistry to study chemical reactions and the conduction of electrons in metal nanowires. The results from these experiments are important for developing ultra-sensitive mass sensors and circuits that use light instead of electrical current to transport information. If successful, this innovation will allow miniaturization of circuits and sensors to nanoscale dimensions. Both graduate and undergraduate students are participating in this research. The undergraduate students are being recruited to the project from the University of Notre Dame, as well as from nearby four-year colleges in the northern Indiana area that have limited research facilities. The undergraduate and graduate students are also involved in a series of outreach activities that connect to local high school students in the South Bend area. The experiments that are being conducted are providing new information about how nano-materials interact with their environment, and how these interactions are different to those of macroscopic objects. The effects that are being explored include the role of surface bound molecules in mediating energy relaxation in nanomaterials, whether simple solvents such as water behave like viscoelastic solvents at nanoscale dimensions, and the way the environment influences the properties of surface plasmon polaritons - which are electromagnetic magnetic waves that propagate at the surfaces of the nanowires. These measurements are being performed using transient absorption microscopy, which is an experimental technique that allows ultrafast laser measurements to be performed on single nano-objects. Simulations are also being conducted as part of the project. Comparison of the experimental results to the simulations is generating information about the properties of the materials that can be used by other researchers in different areas of science and engineering.