Charging and Heating Dynamics of Nanoparticles in Nonthermal Plasmas

提案题目：非热等离子体中纳米粒子的充电和加热动力学。 明尼苏达大学双城分校University of Minnesota Twin Cities 提案编号：CBET-0903842自20世纪80年代以来，“尘埃”或“复杂”等离子体的各个方面一直在激发等离子体群落。第一波兴趣是由微电子器件制造过程中纳米颗粒形成的有害影响引发的。与此同时，强耦合等离子体中令人兴奋的新物理现象的发现催生了复杂等离子体研究的蓬勃发展。最近出现了一个新的关注焦点：使用活性尘埃等离子体作为纳米颗粒的可控源。这些纳米粒子具有有趣的物理和化学性质，使它们有希望用于新的应用。然而，即使经过十多年的研究，这种“纳米尘埃”等离子体的一些最基本的物理过程仍然知之甚少。此外，由于准备良好的“nanodusty”等离子体的实验系统的困难，我们的知识是基于模型，缺乏实验验证。本研究的总体目标是研究纳米粒子充电和加热的基本动力学在高度定义，良好的特征低温等离子体环境。为了实现这一目标，将使用一种独特的工艺来合成高度单分散的发光纳米晶体，其直径在3-20 nm范围内;这些颗粒将被注入精心设计和表征的测试等离子体中。对于纳米粒子充电问题，将与尺寸控制的纳米粒子进行实验，以测试是否轨道运动有限的理论或理论占碰撞效应需要用于小纳米粒子。另一个高风险/高回报的实验将首次尝试测量浸入等离子体中的纳米粒子的电荷分布。这些实验的结果将为相关的建模研究提供新的信息。 对于等离子体中的纳米颗粒加热，将使用“纳米颗粒温度计”进行一系列首次实验，以研究等离子体中单分散纳米颗粒的平均温度，并获得有关其温度分布函数的信息。其中一组实验将利用纳米颗粒光致发光的温度依赖性来获得有关颗粒温度的信息。另一组实验将使用纳米颗粒的微观结构来确定颗粒温度是否达到或超过颗粒？结晶温度这些实验的结果将与粒子加热的数值模型进行比较。这项研究具有广泛的影响。在技术方面，它将为使用等离子体作为纳米技术中使用的功能性纳米颗粒的来源奠定科学基础。它还将作为一个跳板，开展一些教育和外联活动。这些措施包括K-12通过当地公立学区推广;本科生参与研究;在高度跨学科的研究环境中培养研究生和本科生;新的跨学科研究生课程的教学;促进妇女和代表性不足的群体更多地参与我们的研究生研究计划;并积极参与行业。

Proposal Title: Charging and Heating Dynamics of Nanoparticles in Nonthermal PlasmasPrincipal Investigator: Kortshagen, Uwe R. Institution: University of Minnesota-Twin Cities Proposal No: CBET-0903842 Various aspects of "dusty" or "complex" plasmas have continued to excite the plasma com-munity since the 1980s. The first wave of interest was sparked by the detrimental effects of the formation of nanoparticles during the manufacture of microelectronic devices. In parallel, the discovery of exciting new physical phenomena in strongly coupled plasmas gave birth to the booming field of complex plasma studies. Recently a new focus of attention has emerged: Using reactive dusty plasmas as controllable sources of nanoparticles. These nanoparticles have interesting physical and chemical properties that make them promising for novel applications. However, even after more than a decade of study, some of the most basic physical processes of such "nanodusty" plasmas are still poorly understood. Moreover, due to the difficulties of preparing well-characterized experimental systems of "nanodusty" plasmas, most of our knowledge is based on models that lack experimental verification.The overall objective of this research is to study the fundamental dynamics of nanoparticle charging and heating in highly defined, well-characterized low temperature plasma environments. To achieve this objective, a unique process to synthesize highly monodisperse, luminescent nanocrystals with well-defined diameters in the range of 3-20 nm will be used; these particles will be injected into carefully designed and characterized test plasmas. For the nanoparticle charging problem, experiments will be performed with size-controlled nanoparticles to test whether the orbital-motion-limited theory or a theory accounting for collisional effects needs to be used for small nanoparticles. Another high-risk/high-reward experiment will attempt to measure, for the first time, the charge distribution of nanoparticles immersed in a plasma. Results of these experiments will provide new information for accompanying modeling studies. For nanoparticle heating in plasmas, a set of first-ever experiments will be performed using "nanoparticle thermometers" to study the average temperature of monodisperse nanoparticles in plasmas as well as to gain information about their temperature distribution function. One set of experiments will exploit the temperature-dependence of the photoluminescence of nanoparticles to gain information about particle temperatures. Another set of experiments will use the nanoparticles' microstructure to determine whether the particle temperature reached or exceeded the particles? crystallization temperature. Results of these experiments will be compared to numerical models for particle heating.This research has a wide range of broader impacts. On the technical side, it will build the scientific foundation for the use of plasmas as sources of functional nanoparticles for uses in nanotechnology. It will also serve as a springboard for a number of education and outreach activities. These include K-12 outreach through local public school districts; involvement of undergraduates in research; training of graduate and undergraduate students in a highly interdisciplinary research environment; teaching of new interdisciplinary graduate courses; fostering greater involvement of women and underrepresented groups in our graduate research programs; and active engagement with industry.