CAREER: Atomic-Scale Visualization of Excitonic States in Individual Carbon Nanotubes

在这个由化学测量和成像项目资助的项目中，俄勒冈大学的George Nazin教授将开发新的测量技术，用于单个碳纳米管的能量状态的可视化。碳纳米管或“CNTs”是碳元素的一种形式，目前在复合材料中有应用，但在电子学、光电子学和生物成像方面也有潜在的有趣应用。Nazin教授正在研究碳纳米管的电子和光物理性质。Nazin团队正在采用一种空间分辨光谱技术，该技术允许团队获得单个原始碳纳米管和化学修饰碳纳米管的真实空间原子分辨电子地图。这项工作旨在发展碳纳米管光物理的详细图景，这将有助于指导基于碳纳米管的应用的合理设计原则。该项目的目标是通过直接测量碳纳米管中电子激发（激子）对应的电子态的光谱结构和空间行为，建立碳纳米管光物理的定量微观模型。这些研究是由Nazin小组最近建造的一种新型扫描隧道显微镜实现的。在这种实验方法中，隧道电子被用作激发源，这使得碳纳米管光物理研究具有原子尺度的空间分辨率，目前任何其他实验技术都无法实现。除了激子态的直接表征外，单个碳纳米管的空间分辨测量还提供了对激子传输和猝灭的基本重要过程、缺陷在这些过程中的作用以及控制这些过程的化学方法的见解。该项目与Nazin教授与俄勒冈州斯普林菲尔德学区合作开发的初中/高中外展计划相结合。该项目由教师参与设计，以满足州科学标准，通过在俄勒冈大学校园举行的动手科学活动，为学生提供全年参与。

In this project funded by the Chemical Measurement and Imaging Program, Professor George Nazin of the University of Oregon will develop new measurement techniques for the visualization of the energy states of individual carbon nanotubes. Carbon nanotubes, or "CNTs" are a form of the element Carbon which have current applications in composite materials, but also have potential for interesting applications in electronics, optoelectronics and bioimaging. Professor Nazin is investigating the electronic and photophysical properties of CNTs. The Nazin group is employing a spatially-resolved spectroscopic technique that allows the team to obtain real-space atomic-resolution electronic maps of individual pristine and chemically-modified CNTs. This work aims to develop a detailed picture of CNT photophysics, which will help guide the principles for rational design of applications based on CNTs. The goal of the project is to establish a quantitative microscopic model of CNT photophysics through direct measurements of spectral structures and spatial behaviors of electronic states corresponding to electronic excitations (excitons) in CNTs. These studies are enabled by a novel scanning tunneling microscope constructed recently by the Nazin group. In this experimental approach, tunneling electrons are used as the excitation source, which allows investigations of CNT photophysics with atomic-scale spatial resolution, currently inaccessible to any other experimental technique. In addition to the direct characterization of excitonic states, spatially-resolved measurements of individual CNTs provide insights into the fundamentally important processes of exciton transport and quenching, the role of defects in these processes, and chemical approaches to controlling these processes. The project is integrated with a middle/high school outreach program developed by Professor Nazin in collaboration with the Springfield, Oregon, school district. The program, designed with teacher input in order to fulfill state science standards, provides year-round engagement of students through hands-on science activities held at the University of Oregon campus.