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体是一种具有特殊工程电子和光学特性的独特潜力的新型材料。这个项目解决了动态调整收费所提供的可能性。即使在室温下，单个电子也会产生巨大的影响，比如在可见光和红外线下戏剧性地改变纳米晶体的“颜色”。该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一个定义良好的电荷的挑战。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。其次，电荷之间的相互作用很强，它们会极大地影响载流子动力学。在量子点物理学中，内部载流子动力学是一个基础的和知之甚少的主题，在这个项目中，时间分辨光谱将揭示电荷的影响。第三，胶体量子点是“人造原子”，可以通过点与点之间的控制间隔组装成结晶固体。这个项目将研究这种纳米晶体阵列的输运特性，作为每个纳米晶体充电的函数。该项目以高度跨学科的方式整合了研究和教育。它培养学生在纳米科学领域的潜在应用在传感器，照明和通信。自然界中只有大约100种常见元素，但它们的电离程度不同，大大增加了它们化学性质的多样性。例如，氯离子Cl-是一种不活泼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非常有毒的气体。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了原子的电子结构。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”，从而在电子、光学和生物技术方面带来无数的好处，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，来大幅扩展它们的领域。该项目以高度跨学科的方式整合了研究和教育。它培养学生在纳米科学领域的潜在应用在传感器，照明和通信。

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.