SusChEM: Unjamming the Growth of Metal Pnictide Synthesis

纳米级晶体是原子有序的微观粒子，直径比人的头发小大约10万分之一。在这些维度上，纳米粒子呈现出在更大维度的粒子中看不到的有趣的化学和物理性质。纳米结构的化学合成是棘手的，纳米晶体的质量在很大程度上取决于完善的良好合成方法，这种方法通常针对感兴趣的纳米颗粒的化学成分和形态。哥伦比亚大学的乔纳森·欧文博士正在研究新的方法，用新的合成试剂来合成铟和锌磷化物，这种合成试剂提供了更大的灵活性、安全性和对纳米晶体特性的控制。为了分析它们的结构特征，欧文教授使用了一种新颖的前沿技术，称为x射线散射的对分布函数分析。这种方法允许欧文博士选择条件，导致纳米晶体具有更高的纯度和晶体秩序。这个程序揭示了合成是如何发生的机制和项目的结果很容易转移到其他纳米颗粒组合物的合成。这项研究的更广泛的社会影响是开发出毒性更低、地球丰度更高的新材料，并提高了从发光显示器到固态照明和光伏发电等能源技术的性能。欧文教授让高中生、本科生和研究生参与了这个研究项目，并为本科生课程维护了一个量子点合成实验室模块，该模块清楚地说明了量子约束的原理以及晶体成核和生长的机制。III-V和II-V半导体量子点（QDs）的合成落后于典型的II-VI量子点（QDs），目前可以制备出具有优异的单分散性和明亮的光致发光。虽然文献中III-V纳米晶体（nc）的例子少得多，但这些“肽”代表了一个快速发展的领域。哥伦比亚大学的Jonathan Owen教授通过设计具有可调节转化反应活性的pnicogen前体，研究金属pnictide纳米颗粒的合成方法。通过使用高温相容的表面活性剂和结晶催化剂加速结晶动力学来实现额外的控制，以促进快速可逆的键形成。III-V和II-V量子点的合成方法，重点是锌和铟的磷化物和砷化物，是最初的核苷酸目标组合物，但获得的信息通常可转移到其他核苷酸材料。这项拟议研究的更广泛影响来自于开发具有降低毒性，地球丰度和提高能源技术效率的新材料，其应用范围从发光显示器到固态照明和光伏。欧文教授让高中生、本科生和研究生参与这个研究项目。他还致力于将对量子点特性的更好理解带入本科实验室，开发一个量子点合成实验室模块，清楚地说明了量子限制的原理和晶体成核和生长的机制。

Nanoscaled crystals are atomically-ordered microscopic particles that are approximately 100,000 smaller in diameter than a human hair. At these dimensions, the nanoparticles take on interesting chemical and physical properties not seen in larger dimensioned particles. The chemical synthesis of nanostructures is tricky, and the quality of the nanocrystal depends heavily on perfecting a good synthetic methodology, which is often specific to the chemical composition and morphology of the nanoparticle of interest. Dr. Jonathan Owen of Columbia University is researching new methods to synthesize indium and zinc phosphides with novel synthesis reagents that provide greater flexibility, safety, and control of the nanocrystal properties. To analyze their structural characteristics, Prof. Owen uses a novel and cutting edge technique called pair distribution function analysis of x-ray scattering. This approach allows Dr. Owen to select for conditions that lead to nanocrystals with greater purity and crystalline order. This program is shedding light on how the syntheses take place mechanistically and results of the project readily transfer to synthesis of other nanoparticle compositions. Broader societal impacts of the research are the development of new materials with reduced toxicity, earth abundance, and improved performance in energy technologies from luminescent displays, to solid state lighting, and photovoltaics. Prof. Owen involves high school, undergraduate, and graduate students in this research project and maintains a quantum dot synthesis laboratory module for undergraduate courses that clearly illustrates the principles of quantum confinement and the mechanisms of crystal nucleation and growth.The synthesis of III-V and II-V semiconductor quantum dots (QDs) has lagged behind that of the canonical II-VI QDs, which can be presently fabricated with outstanding monodispersity and bright photoluminescence. While there are many fewer examples of III-V nanocrystals (NCs) in the literature, these "pnictides" represent a rapidly developing field. Prof. Jonathan Owen of Columbia University is researching synthesis methods of metal pnictide nanoparticles by designing pnictogen precursors with tunable conversion reactivity. Additional control is achieved by speeding the crystallization kinetics using high temperature compatible surfactants and crystallization catalysts to facilitate rapid and reversible bond formation. Methodology for the synthesis of III-V and II-V QDs, with an emphasis on phosphides and arsenides of zinc and indium, are the initial pnictide target compositions, but the information obtained is generally transferable to other pnitide materials. The broader impacts of this proposed research result from the development of new materials with reduced toxicity, earth abundance, and improved efficiencies in energy technologies with applications ranging from luminescent displays to solid state lighting and photovoltaics. Prof. Owen involves high school, undergraduate, and graduate students in this research project. He also works to bring an improved understanding of QD properties into the undergraduate laboratory in developing a QD synthesis lab module that clearly illustrates the principles of quantum confinement and the mechanisms of crystal nucleation and growth.