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

在这个由化学测量和成像计划资助的项目中，俄勒冈州大学的乔治纳津教授将开发新的测量技术，用于可视化单个碳纳米管的能量状态。 碳纳米管或“CNT”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中也有潜在的有趣应用。 Nazin教授正在研究CNT的电子和电子物理特性。Nazin小组正在采用一种空间分辨光谱技术，使该小组能够获得单个原始和化学修饰的CNT的真实空间原子分辨率电子地图。这项工作的目的是发展一个详细的CNT物理，这将有助于指导原则，合理设计的应用程序的基础上，碳纳米管。该项目的目标是通过直接测量CNT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CNT电子物理的定量微观模型。这些研究是由一种新的扫描隧道显微镜最近建造的纳津组。在这种实验方法中，隧穿电子被用作激发源，这使得碳纳米管电子物理学的调查与原子尺度的空间分辨率，目前无法访问任何其他实验技术。除了激子状态的直接表征外，单个CNT的空间分辨测量还提供了对激子传输和淬灭的根本重要过程、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。该计划，与教师的投入，以满足国家科学标准的设计，通过在俄勒冈州校园举行的动手科学活动提供学生全年参与。

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.