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首页> 外文学位 >Application of luminescence sensors in oxygen diffusion measurement and study of luminescence enhancement/quenching by metallic nanoparticles .
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Application of luminescence sensors in oxygen diffusion measurement and study of luminescence enhancement/quenching by metallic nanoparticles .

机译：发光传感器在氧扩散测量和金属纳米粒子发光增强/猝灭研究中的应用。

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摘要

The first part of this dissertation deals with the application of a luminescence quenching method to measure diffusion and permeation coefficients of oxygen in polymers. Most luminescence oxygen sensors do not follow linearity of the Stern-Volmer (SV) equation due to heterogeneity of luminophore in the polymer matrix, thus the complexity of data analysis is increased. To circumvent this limitation, inverted fluorescence microscopy is utilized in this work to investigate the SV response of the sensors at the micron-scale. In these diffusion experiments, oxygen concentration is measured by luminescence changes in regions with high SV constants and good linearity. Thus, we avoid numerical complexity of combining nonlinear SV equation with a diffusion model. This technique allows us to measure oxygen diffusion properties in different type of polymers like transparent, opaque, free-standing polymers and polymers that cannot be cast into free standing films and polymer composites.;In the second part of this thesis, we have explored the effect of Ag-Cu alloy nanoparticles on the emission intensity of luminophores at their close proximity. Alloy nanoparticles offer additional degrees of freedom for tuning their optical properties by altering atomic composition and atomic arrangement and thus can be an attractive option for manipulating signal of a wide range of luminophores. In this work, surface plasmon xi resonance spectrum of Ag-Cu alloy nanoparticles deposited by sputtering was easily tuned in wide wavelength range by varying one experimental condition- annealing temperature. Large metal enhanced luminescence for different luminophores viz Alexa Fluor 594 and Alexa Fluor 488 were achieved at the vicinity of Ag-Cu nanoparticles when maximum spectral overlap between SPR spectra of Ag-Cu nanoparticles and the emission and absorption spectra of the luminophores occur. We also studied the effect of composition of Ag-Cu nanoparticles synthesized by the polyol process on the luminescence of low quantum yield dye Cy3.;In the third part of this thesis, quenching effect of Cu nanoparticles on CdSe/ZnS nanocrystal quantum dots has been explored. As Cu nanoparticles have comparable dielectric properties with gold nanoparticles, they are expected to show similar quenching effects. It was found that Cu is an efficient quencher of fluorescence from CdSe/ZnS quantum dots and the quenching effect is due to resonance energy transfer from quantum dots to Cu nanoparticles.
机译：本文的第一部分涉及发光猝灭法的应用，以测量聚合物中氧的扩散系数和渗透系数。由于聚合物基体中发光体的异质性，大多数发光氧传感器不遵循Stern-Volmer（SV）方程的线性，因此增加了数据分析的复杂性。为了避免这种局限性，在这项工作中采用了倒置荧光显微镜技术来研究微米级传感器的SV响应。在这些扩散实验中，通过具有高SV常数和良好线性的区域中的发光变化来测量氧浓度。因此，我们避免了将非线性SV方程与扩散模型组合在一起的数值复杂性。这项技术使我们能够测量不同类型的聚合物中的氧扩散特性，例如透明，不透明，自立式聚合物和不能浇铸成自立式膜和聚合物复合材料的聚合物。在本论文的第二部分，我们探索了-Cu合金纳米粒子对发光体近距离发光强度的影响。合金纳米粒子通过改变原子组成和原子排列，提供了更多自由度来调节其光学性能，因此对于操纵各种发光体信号可能是一个有吸引力的选择。在这项工作中，通过改变一种实验条件-退火温度，可以很容易地在宽波长范围内调节通过溅射沉积的Ag-Cu合金纳米颗粒的表面等离子体共振光谱。当Ag-Cu纳米颗粒的SPR光谱与发光体的发射和吸收光谱之间出现最大光谱重叠时，在Ag-Cu纳米颗粒附近获得了不同发光体的大金属增强发光，即Alexa Fluor 594和Alexa Fluor 488。我们还研究了多元醇法合成的Ag-Cu纳米粒子的组成对低量子产率染料Cy3发光的影响。第三部分，研究了Cu纳米粒子对CdSe / ZnS纳米晶体量子点的猝灭作用。探索。由于铜纳米颗粒具有与金纳米颗粒相当的介电性能，因此有望显示出相似的猝灭效果。发现Cu是来自CdSe / ZnS量子点的荧光的有效猝灭剂，并且猝灭效果归因于从量子点到Cu纳米颗粒的共振能量转移。

著录项

  • 作者

    Chowdhury, Sanchari.;

  • 作者单位

    University of South Florida.;

  • 授予单位 University of South Florida.;
  • 学科 Engineering Chemical.
  • 学位 Ph.D.
  • 年度 2010
  • 页码 161 p.
  • 总页数 161
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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