Charging and Heating Dynamics of Nanoparticles in Nonthermal Plasmas

提案标题：纳米颗粒在非热等离子体中的充电和加热动力学主要研究人员：Kortshagen，Uwe R.研究所：明尼苏达大学双子城分校提案编号：CBET-0903842自1980年代以来，“尘埃”或“复杂”等离子体的各种方面一直在刺激等离子体通信。第一波兴趣是由微电子设备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领域。最近出现了一个新的关注焦点：使用反应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，这使它们在新的应用中具有广阔的前景。然而，即使经过了十多年的研究，人们仍然很少了解这种带有纳米尘埃的等离子体的一些最基本的物理过程。此外，由于制备特征良好的纳米尘埃等离子体实验系统的困难，我们的大部分知识都是基于缺乏实验验证的模型。本研究的总体目标是研究高度定义的、特征良好的低温等离子体环境中纳米粒子充电和加热的基本动力学。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，这些颗粒的直径在3-20 nm范围内定义良好；这些颗粒将被注入精心设计和表征的测试等离子体中。对于纳米粒子的荷电问题，将用尺寸可控的纳米粒子进行实验，以检验小纳米粒子是否需要使用轨道运动限制理论或考虑碰撞效应的理论。另一项高风险/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伴随的建模研究提供新的信息。对于纳米粒子在等离子体中的加热，将首次使用纳米粒子温度计进行一系列实验，以研究单分散纳米粒子在等离子体中的平均温度，并获得关于其温度分布函数的信息。其中一组实验将利用纳米粒子的光致发光的温度依赖性来获得有关粒子温度的信息。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更广泛的影响。在技术方面，它将为将等离子体用作纳米技术中功能纳米颗粒的来源奠定科学基础。它还将成为开展一些教育和外联活动的跳板。这些措施包括通过当地公立学区的K-12扩展；本科生参与研究；在高度跨学科的研究环境中培训研究生和本科生；教授新的跨学科研究生课程；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项目；以及积极参与行业。

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.