Author: Mouzah Mohammad Arrubban
Publisher:
ISBN:
Category :
Languages : en
Pages : 121

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Author: mouzah mohamed bin khalid" "arrubban
Publisher:
ISBN:
Category :
Languages : ar
Pages : 134

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Author: Florian Abeles
Publisher:
ISBN:
Category :
Languages : en
Pages : 29

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The influence of structural defects on the optical properties of thin vacuum-evaporated films of silver has been investigated. The technique of preparation and control of the annealing are described. The crystallographic structure of the films has been examined by transmission electron microscopy. The possibilities of further improving the structure of the films is discussed. The optical absorption is due to various mechanisms which were carefully separated: intraband and interband transitions and plasma oscillations. It was found that the optical mass mo of the conduction electrons is definitely smaller than unity (0.86

Author: D. B. Barker
Publisher:
ISBN:
Category : Metallic films
Languages : en
Pages : 16

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Author: Kelvin Fraser Poole
Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 150

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Author: Winifred Lewis
Publisher:
ISBN:
Category : Aluminum
Languages : en
Pages : 144

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Author: Winifred Lewis
Publisher:
ISBN:
Category : Aluminum
Languages : en
Pages : 94

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Author: Shangzhi Chen
Publisher: Linköping University Electronic Press
ISBN: 9179297455
Category :
Languages : en
Pages : 142

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Intrinsically conducting polymers forms a category of doped conjugated polymers that can conduct electricity. Since their discovery in the late 1970s, they have been widely applied in many fields, ranging from optoelectronic devices to biosensors. The most common type of conducting polymers is poly(3,4-ethylenedioxythiophene), or PEDOT. PEDOT has been popularly used as electrodes for solar cells or light-emitting diodes, as channels for organic electrochemical transistors, and as p-type legs for organic thermoelectric generators. Although many studies have been dedicated to PEDOT-based materials, there has been a lack of a unified model to describe their optical properties across different spectral ranges. In addition, the interesting optical properties of PEDOT-based materials, benefiting from its semi-metallic character, have only been rarely studied and utilized, and could potentially enable new applications. Plasmonics is a research field focusing on interactions between light and metals, such as the noble metals (gold and silver). It has enabled various opportunities in fundamental photonics as well as practical applications, varying from biosensors to colour displays. This thesis explores highly conducting polymers as alternatives to noble metals and as a new type of active plasmonic materials. Despite high degrees of microstructural disorder, conducting polymers can possess electrical conductivity approaching that of poor metals, with particularly high conductivity for PEDOT deposited via vapour phase polymerization (VPP). In this thesis, we systematically studied the optical and structural properties of VPP PEDOT thin films and their nanostructures for plasmonics and other optical applications. We employed ultra-wide spectral range ellipsometry to characterize thin VPP PEDOT films and proposed an anisotropic Drude-Lorentz model to describe their optical conductivity, covering the ultraviolet, visible, infrared, and terahertz ranges. Based on this model, PEDOT doped with tosylate (PEDOT:Tos) presented negative real permittivity in the near infrared range. While this indicated optical metallic character, the material also showed comparably large imaginary permittivity and associated losses. To better understand the VPP process, we carefully examined films with a collection of microstructural and spectroscopic characterization methods and found a vertical layer stratification in these polymer films. We unveiled the cause as related to unbalanced transport of polymerization precursors. By selection of suitable counterions, e.g., trifluoromethane sulfonate (OTf), and optimization of reaction conditions, we were able to obtain PEDOT films with electrical conductivity exceeding 5000 S/cm. In the near infrared range from 1 to 5 µm, these PEDOT:OTf films provided a well-defined plasmonic regime, characterized by negative real permittivity and lower magnitude imaginary component. Using a colloidal lithography-based approach, we managed to fabricate nanodisks of PEDOT:OTf and showed that they exhibited clear plasmonic absorption features. The experimental results matched theoretical calculations and numerical simulations. Benefiting from their mixed ionic-electronic conducting characters, such organic plasmonic materials possess redox-tunable properties that make them promising as tuneable optical nanoantennas for spatiotemporally dynamic systems. Finally, we presented a low-cost and efficient method to create structural colour surfaces and images based on UV-treated PEDOT films on metallic mirrors. The concept generates beautiful and vivid colours through-out the visible range utilizing a synergistic effect of simultaneously modulating polymer absorption and film thickness. The simplicity of the device structure, facile fabrication process, and tunability make this proof-of-concept device a potential candidate for future low-cost backlight-free displays and labels.

Author: Thomas Aird McLauchlan
Publisher:
ISBN:
Category : Metallic films
Languages : en
Pages : 4

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Author: Luis Berbil-Bautista
Publisher:
ISBN:
Category :
Languages : en
Pages : 57

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