Step-wise Assembly of Nanocrystal Synthons for Precision Doping

在化学系大分子、超分子和纳米化学项目的支持下，马萨诸塞州阿默斯特大学的Kevin Kittilstved教授将研究可用作制备半导体纳米晶体或量子点前体的团簇的形成。 半导体纳米晶体可用于广泛的光电子学、传感和生物医学成像应用。 将少量化学杂质（或掺杂剂）故意掺入半导体纳米晶体中引入了可调的功能和新颖的性质。 本研究旨在深入了解掺杂半导体团簇的形成机理，并开发一种自底向上的合成方法，以精确控制掺杂剂的水平和分布。 该项目将通过使用先进技术对研究生和本科生进行化学合成和表征培训，为STEM领域的熟练劳动力做好准备。 Kittilstved小组的成员将参与开发和执行尤里卡的动手实验室体验！该项目由霍利奥克女孩公司和马萨诸塞州阿默斯特大学自然科学学院组织。为了促进小组成员之间的有效合作，Kittilstved博士和他的研究团队将参与马萨诸塞州阿默斯特大学研究生院提供的各种研究指导和专业发展研讨会。该项目的长期目标是建立化学参数，以促进魔法大小簇内目标杂质离子的精确掺杂，这些杂质离子是量子点，纳米线和纳米片合成中的关键亚稳前体。 为了实现这一目标，Kittilstved博士领导的团队将首先研究单核前体和多核CdS分子簇中过渡金属掺杂剂对神奇尺寸簇形成机制的影响，并确定哪些化学因素促进分子簇逐步组装成精确掺杂的神奇尺寸簇。 结合本研究的合成方面，该团队将使用常规和最先进的光谱和分析方法来表征魔法大小簇中的掺杂剂形态，研究魔法大小簇形成的动力学，并跟踪电子结构从分子到量子限制机制的演变。 该研究致力于提供基础知识，为自旋电子学或光电子学应用提供高质量和均匀掺杂的设计师半导体纳米结构的合理设计。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With the support of the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry, Professor Kevin Kittilstved of the University of Massachusetts Amherst will study the formation of clusters that can be used as precursors for preparing semiconductor nanocrystals or quantum dots. Semiconductor nanocrystals are useful for a wide range of optoelectronics, sensing, and biomedical imaging applications. The deliberate incorporation of a small amounts of chemical impurities (or dopants) into the semiconductor nanocrystals introduces tunable functionality and novel properties. This research aims to gain a thorough understanding of the formation mechanism of doped semiconductor clusters and to develop a bottom-up synthetic approach to enable precise control of the dopant level and distribution. This project will contribute to the preparation of a skilled workforce in STEM fields by training graduate and undergraduate students in chemical synthesis and characterization using sophisticated techniques. Members of the Kittilstved group supported by this funding will be involved in developing and executing a hands-on lab experience for the Eureka! Program organized by Girls Inc of Holyoke and the College of Natural Sciences at the University of Massachusetts Amherst. To facilitate effective collaboration amongst group members, Dr. Kittilstved and his research team will engage with the various research mentoring and professional development workshops available through the Graduate School at the University of Massachusetts Amherst. The long-term goal of this project is to establish the chemical parameters that promote precise doping of targeted impurity ions within magic-size clusters, which are known to be critical metastable precursors in the synthesis of quantum dots, nanowires, and nanoplatelets. To achieve this goal, the team led by Dr. Kittilstved will first examine the effect of transition metal dopants in mononuclear precursors and multinuclear CdS-based molecular clusters on the formation mechanism of magic-size clusters and determine what chemical factors promote stepwise assembly of molecular clusters into a precisely doped magic-size clusters. In conjunction with the synthetic aspect of this study, this team will use conventional and state-of-the-art spectroscopic and analytical methods to characterize dopant speciation in the magic-size clusters, to study the kinetics of magic-size cluster formation, and to follow the evolution of the electronic structure from the molecular to the quantum confinement regime. This research strives to provide fundamental knowledge to inform the rational design of high-quality and homogeneously doped designer semiconductor nanostructures for spin-based electronics or optoelectronics applications.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.