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首页> 外文学位 >Aerosol synthesis and surface functionalization of luminescent silicon nanoparticles, aerosol synthesis of magnetic nanoparticles, and kinetic Monte Carlo simulation of silicon nanoparticle nucleation.
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Aerosol synthesis and surface functionalization of luminescent silicon nanoparticles, aerosol synthesis of magnetic nanoparticles, and kinetic Monte Carlo simulation of silicon nanoparticle nucleation.

机译：发光硅纳米粒子的气溶胶合成和表面功能化，磁性纳米粒子的气溶胶合成以及硅纳米粒子成核的动力学蒙特卡罗模拟。

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The primary accomplishment of the research presented in this thesis is the development of a technology to produce light emitting silicon nanoparticles in macroscopic quantities by gas phase laser-driven pyrolysis of silane and post etching treatment. Theoretical exploration of the homogenous gas phase particle nucleation during pyrolysis of silane is another parallel focus of this thesis.; Production of nano-scale materials by CO2 laser-driven gas phase reactions has been studied by several groups during the past two decades. The particle sizes can be controlled to below 10 nm. Although the silicon nanoparticles that are produced by this method are not photoluminescent, we have discovered that etching these particles with HF/HNO3 mixture can controllably reduce their size and passivate their surface such that they become photoluminescent. The photoluminescence can be controlled by the etching conditions. In order to obtain silicon nanoparticles with stable photoluminescence properties and stable colloidal dispersions for further applications, it is important to passivate the silicon nanoparticle surfaces and coat them with functional groups. Well-dispersed particle dispersions with stable PL were obtained after surface functionalization. This provides an important step toward the further potential applications of silicon nanoparticles.; One key advantage of the gas phase laser pyrolysis process is the flexibility to make nanoparticles of different materials. Nickel and iron nanoparticles were produced successfully with controlled size distribution. Preliminary results show that this method is capable of producing metallic nanoparticles with interesting magnetic properties.; Kinetic Monte Carlo simulation of particle nucleation during thermal decomposition of silane can also be used to obtain useful information about the synthesis of silicon nanoparticles. In this approach, a simulation follows the evolution of a single silicon-hydrogen cluster as it reacts with its environment and grows, possibly to eventually become a particle, or disintegrates. An improved group additivity method is used to estimate the thermochemical properties of silicon-hydrogen clusters, and thermochemically-based reactivity rules are used to estimate the rate parameters for reactions of these clusters. Useful information, such as free energy profiles, cluster size distributions, effective reaction rate constants and critical particle nucleus sizes, can be extracted from the kinetic Monte Carlo simulations.
机译：本文提出的研究的主要成就是通过气相激光驱动的硅烷热解和后蚀刻处理来生产宏观量的发光硅纳米粒子的技术的发展。硅烷热解过程中均相气相颗粒成核的理论探索是本论文的另一个重点。在过去的二十年中，已经有几组研究了通过CO 2 激光驱动的气相反应生产纳米级材料。颗粒尺寸可以控制在10nm以下。尽管通过这种方法生产的硅纳米颗粒不是光致发光的，但我们发现用HF / HNO 3 混合物蚀刻这些颗粒可以可控地减小其尺寸并钝化其表面，从而使其成为光致发光的。可以通过蚀刻条件来控制光致发光。为了获得具有稳定的光致发光性能和稳定的胶态分散体的硅纳米颗粒以用于进一步的应用，重要的是钝化硅纳米颗粒表面并用官能团涂覆它们。表面官能化后，获得具有稳定PL的分散良好的颗粒分散体。这为硅纳米颗粒的进一步潜在应用提供了重要的一步。气相激光热解工艺的一个关键优势是可以灵活地制造不同材料的纳米颗粒。镍和铁纳米颗粒的生产成功，尺寸分布可控。初步结果表明，该方法能够制备具有令人感兴趣的磁性的金属纳米颗粒。硅烷热分解过程中颗粒成核的动力学蒙特卡洛模拟也可用于获得有关硅纳米颗粒合成的有用信息。在这种方法中，当单个硅-氢簇与周围环境发生反应并生长时，可能会进行仿真，最终可能变成颗粒或崩解。改进的基团加和方法用于估算硅氢簇的热化学性质，基于热化学的反应性规则用于估算这些簇的反应速率参数。有用的信息，例如自由能分布，团簇尺寸分布，有效反应速率常数和关键粒子核尺寸，可以从动力学蒙特卡洛模拟中提取。

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