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Synthesis, growth kinetics and optical properties of zinc oxide nanoparticle suspensions and thin films.

机译：氧化锌纳米颗粒悬浮液和薄膜的合成，生长动力学和光学性质。

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Colloidal chemistry techniques were used to synthesize ZnO particles in the nanometer size regime. The particle aging kinetics were determined by monitoring the optical band edge absorption and using the effective mass model to approximate the particle size as a function of time. The growth kinetics of the ZnO particles were found to follow the Lifshitz, Slyozov, Wagner theory for Ostwald ripening. In this model, the higher curvature and hence chemical potential of smaller particles provides a driving force for dissolution. The larger particles continue to grow by diffusion limited transport of species dissolved in solution.; Thin films of ZnO quantum particles were fabricated by electrophoretic deposition from suspensions prepared via a colloidal chemistry synthesis route. Films were prepared at constant current thus eliminating the limited deposition rate associated with constant voltage deposition. The kinetics for the deposition of thin films were determined using optical absorbance techniques in conjunction with atomic absorption spectrometry. The particle velocity during deposition and the charge on the particles were determined from the deposition kinetics.; The thin films prepared by electrophoretic deposition exhibited optical properties characteristic of the quantum size particles. The average particle size, and hence the optical properties, were tailored by controlling the aging time and temperature of the suspensions. Both the band-to-band and visible photoluminescence were progressively blue shifted, relative to the bulk value, with decreasing particle size in the film. A linear dependence was found between the band-to-band and visible emission.; Finally, particle growth was manipulated by the specific adsorption of a series of capping ligands at the particle surface. The adsorption of the capping ligands was found to produce a diffusion barrier such that particle growth was stunted following incorporation with the extent of this effect being dependent upon concentration and selection of ligand. Preliminary experiments aimed at producing 2-D ordered monolayers and electrostatically trapped particle chains were performed and provide a foundation for further refinement.
机译：胶体化学技术用于合成纳米尺寸的ZnO颗粒。通过监测光学带边缘吸收并使用有效质量模型来近似随时间变化的粒度来确定颗粒老化动力学。发现ZnO颗粒的生长动力学遵循Lostshitz，Slyozov，Wagner理论进行的Ostwald熟化。在该模型中，较高的曲率以及较小颗粒的化学势提供了溶解的驱动力。较大的颗粒通过溶解在溶液中的物质的扩散受限运输而继续生长。 ZnO量子粒子的薄膜是通过电泳沉积从胶体化学合成途径制备的悬浮液中制备的。以恒定电流制备膜，从而消除了与恒定电压沉积相关的有限沉积速率。使用光吸收技术结合原子吸收光谱法确定薄膜沉积的动力学。由沉积动力学确定沉积期间的颗粒速度和颗粒上的电荷。通过电泳沉积制备的薄膜表现出量子尺寸颗粒的光学特性。通过控制悬浮液的老化时间和温度来调整平均粒径，从而调节光学性能。相对于整体值，带间和可见光致发光都逐渐蓝移，并且膜中的颗粒尺寸减小。发现在频带间和可见光发射之间存在线性关系。最后，通过一系列在颗粒表面的封端配体的特异性吸附来控制颗粒的生长。发现封端配体的吸附产生扩散阻挡，使得掺入后颗粒生长受阻，该作用的程度取决于配体的浓度和选择。进行了旨在产生二维有序单层膜和静电捕获粒子链的初步实验，并为进一步改进奠定了基础。

著录项

  • 作者

    Wong, Eva May.;

  • 作者单位

    The Johns Hopkins University.;

  • 授予单位 The Johns Hopkins University.;
  • 学科 Engineering Materials Science.; Engineering Chemical.; Chemistry Inorganic.
  • 学位 Ph.D.
  • 年度 2000
  • 页码 p.1037
  • 总页数 229
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 工程材料学;
  • 关键词

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