Reduced and Oxidized Colloid Quantum Dots: Photophysics and Transport

具有可控成分、尺寸和形状的半导体纳米晶是一种具有独特潜力的新型材料，具有特殊的工程电子和光学性能。该项目解决了通过动态调整充电提供的可能性。即使在室温下，一个单一的电子也会产生巨大的影响，比如在可见光和红外下都会戏剧性地改变纳米晶体的“颜色”。这个项目将首先解决在一个小的胶体量子点中可控地注入和保留明确定义的电荷的挑战。这是一个界面氧化还原化学问题，需要一个耦合的合成和表征方法。第二，电荷之间的相互作用很强，它们应该对载流子动力学有很大的影响。内载流子动力学是量子点物理学中一个基本而又知之甚少的课题，在这个项目中，时间分辨光谱学将阐明电荷的影响。第三，胶体量子点是“人造原子”，它们可以组装成晶态固体，点与点之间有可控的间隔物。这个项目将研究这种纳米晶体阵列的传输特性作为每个纳米晶体的电荷的函数。该项目以高度跨学科的方式将研究和教育结合在一起。它培训学生在纳米科学领域的潜在应用于传感器，照亮了通信。自然界中只有大约100种常见元素，但它们的化学种类因其不同程度的电离而大大增强。例如，氯离子Cl-是一种没有活性但对生命至关重要的元素，而氯分子C12是第一次世界大战中使用的剧毒气体。在过去的二十年里，材料科学家已经在很大程度上控制了非常小的半导体晶体的合成和组装，这些晶体在许多方面模仿原子的电子结构。通过设计“纳米晶体”的大小、形状和组成，人们现在有可能设计出超“人造原子”，从而有望在电子、光学和生物技术方面带来无数好处，而其中一些已经开始实现。该项目将提供基础研究，通过控制这些新的“人造原子”的不同电离程度，极大地扩大它们的领域。该项目以高度跨学科的方式将研究和教育结合在一起。它培训学生在纳米科学领域，在传感器、照明和通信方面有潜在的应用。

Semiconductor Nanocrystals with controlled composition, size and shape are novel materials with the unique potential for specifically engineered electronic and optical properties. This project addresses the possibilities afforded by dynamically tuning the charges. One single electron has large consequences even at room temperature, such as dramatically switching the "color" of a nanocrystal both in the visible and in the infrared. This project will first address the challenges to controllably inject and retain a well-defined charge in a small colloid quantum dot. This is an interfacial redox chemistry problem, which requires a coupled synthetic and characterization approach. Second, charges strongly interact with one another and they should greatly influence the carrier dynamics. Internal carrier dynamics is a basic and poorly understood subject in quantum dot physics and in this project, time-resolved spectroscopy will shed light on the influence of charges. Third, colloidal quantum dots are "artificial atoms", which can be assembled into crystalline solids with controlled spacers between dots. This project will investigate the transport properties of such nanocrystal arrays as a function of the charging of each nanocrystals. The project integrates research and education in a highly interdisciplinary fashion. It trains students in an area of nanoscience with potential applications in sensors, lighting a communications.There are only about 100 common elements in Nature but the variety of their chemistry is greatly enhanced by their various degrees of ionization. For example, the Chlorine ion Cl- is an unreactive but essential element for life, while the Chlorine molecule, C12, was the very poisonous gas used in World War I. Over the past twenty years material scientists have achieved a great degree of control of the synthesis and assemblies of very small crystals of semiconductors that mimic in many ways the electronic structure of atoms. By designing size, shape and composition of the "nanocrystals", one has now the possibility of designing supra "artificial atoms", from which countless benefits in electronic, optical and biological technologies are expected while several are already starting to be realized. The project will provide the basic research to dramatically expand the realm of these new "artificial atoms" by controlling their various degrees of ionization. The project integrates research and education in a highly interdisciplinary fashion. It trains students in an area of nanoscience with potential applications in sensors, lighting and communications.