SusChEM: Unjamming the Growth of Metal Pnictide Synthesis

纳米晶体是原子级的微观粒子，直径比人类头发小大约100，000。 在这些尺寸下，纳米颗粒呈现出在较大尺寸颗粒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，纳米结构的质量在很大程度上取决于完善良好的合成方法，这通常是特定于感兴趣的纳米颗粒的化学组成和形态。 哥伦比亚大学的Jonathan Owen博士正在研究用新型合成试剂合成磷化铟和磷化锌的新方法，这些新方法提供了更大的灵活性、安全性和对磷化物性质的控制。 为了分析它们的结构特征，Owen教授使用了一种新颖的尖端技术，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导致纳米晶体具有更高纯度和晶体有序性的条件。 该计划揭示了合成是如何机械地发生的，并且该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毒性降低、地球丰度增加的新材料，以及改善从发光显示器到固态照明和光化学的能源技术性能。Owen教授的研究项目涉及高中生、本科生和研究生，并为本科生开设了一个量子点合成实验室模块，该模块清晰地说明了量子限制的原理以及晶体成核和生长的机制。III-V族和II-V族半导体量子点（QD）的合成落后于典型的II-VI族QD，其目前可以制造成具有突出的单分散性和明亮的光致发光。 虽然文献中III-V族纳米晶体（NC）的实例少得多，但这些“磷属元素化物”代表了快速发展的领域。 哥伦比亚大学的Jonathan Owen教授正在研究通过设计具有可调转化反应性的磷属元素前体来合成金属磷属元素化物纳米颗粒的方法。 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以促进快速和可逆的键形成来实现额外的控制。用于合成III-V和II-V QD的方法，重点是锌和铟的磷化物和砷化物，是初始磷属元素化物目标组合物，但所获得的信息通常可转移到其他磷属元素化物材料。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致发光。欧文教授涉及高中，本科和研究生在这个研究项目。他还致力于将对量子点性质的更好理解带入本科实验室，开发了一个量子点合成实验室模块，该模块清楚地说明了量子限制的原理以及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.