Optics Of Conducting Polymer Thin Films And Nanostructures

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.

Very thin film materials have emerged as a highly interesting and useful quasi 2D-state functionality. They have given rise to numerous applications ranging from protective and smart coatings to electronics, sensors and display technology as well as serving biological, analytical and medical purposes. The tailoring of polymer film properties and functions has become a major research field. As opposed to the traditional treatise on polymer and resin-based coatings, this one-stop reference is the first to give readers a comprehensive view of the latest macromolecular and supramolecular film-based nanotechnology. Bringing together all the important facets and state-of-the-art research, the two well-structured volumes cover film assembly and depostion, functionality and patterning, and analysis and characterization. The result is an in-depth understanding of the phenomena, ordering, scale effects, fabrication, and analysis of polymer ultrathin films. This book will be a valuable addition for Materials Scientists, Polymer Chemists, Surface Scientists, Bioengineers, Coatings Specialists, Chemical Engineers, and Scientists working in this important research field and industry.

Conducting Polymers with Micro or Nanometer Structure describes a topic discovered by three winners of the Nobel Prize in Chemistry in 2000: Alan J. Heeger, University of California at Santa Barbara, Alan G. MacDiarmid at the University of Pennsylvania, and Hideki Shirakawa at the University of Tsukuba. Since then, the unique properties of conducting polymers have led to promising applications in functional materials and technologies. The book first briefly summarizes the main concepts of conducting polymers before introducing micro/nanostructured conducting polymers dealing with their synthesis, structural characterizations, formation mechanisms, physical and chemical properties, and potential applications in nanomaterials and nanotechnology. The book is intended for researchers in the related fields of chemistry, physics, materials, nanomaterials and nanodevices. Meixiang Wan is a professor at the Institute of Chemistry, Chinese Academy of Sciences, Beijing.

The new millennium has brought fourth many technological innovations made possible by the advancement of high speed integrated circuits. The materials and energy requirements for a microchip is orders of magnitude higher than that of "traditional" goods, and current materials management requirements for EHS friendly low-k processing require a 10% annual increase in raw materials utilization. Initiated Chemical Vapor Deposition (iCVD) is a low-energy, one step, solvent-free process for producing polymeric thin films This thesis describes the deposition of a novel low-k iCVD precursor, 1,3,5,7-tetravinyltetramethylcylcotetrasiloxane (V4D4). The high degree of organic content in the as-deposited film affords the ability to tune the film's properties by annealing. The incorporation of atmospheric oxygen at high temperatures enhances the mechanical and electrical properties of the films. Films annealed at 410'C have a dielectric constant of 2.15, hardness and modulus of 0.78 GPa and 5.4 GPa, respectively. These values are comparatively better than previously reported results for CVD low-k films. Environmentally friendly low-k processing encompasses materials and energy management in the entire integration process, including lithography. Colloidal lithography was combined with iCVD and capillary force lithography to create spatially addressable grafted polymer pattern nanostructures, without the need for expensive lithography tools. Using this method, we pattern our novel low dielectric constant polymer down to 25 nm without the need for environmentally harmful solvents. Furthermore, these grafted patterns were produced for a broad material set of functional organic, fluorinated, and silicon containing polymers. A variation of this process created amine functionalized biocompatible conducting polymer nanostructure patterns for biosensor applications. These were fabricated using grafting reactions between oxidative chemical vapor deposition (oCVD) PEDOT conducting polymers and amine functionalized polystyrene (PS) colloidal templates. Carboxylate containing oCVD copolymer patterns were used to immobilized fluorescent dyes. Fluorescent colloidal particles were assembled within dyed PEDOT-co-TAA copolymer nanobowl templates to create bifunctional patterns for optical data storage applications. Finally, UV and e-beam lithography were used to pattern covalently tethered vinyl monolayers for resist-free patterning of iCVD and oCVD polymers, using environmentally innocuous solvents.

Due to their unique size-dependent physicochemical properties, nanostructured thin films are used in a wide range of applications from smart coating and drug delivery to electrocatalysis and highly-sensitive sensors. Depending on the targeted application and the deposition technique, these materials have been designed and developed by tuning their atomic-molecular 2D- and/or 3D-aggregation, thickness, crystallinity, and porosity, having effects on their optical, mechanical, catalytic, and conductive properties. Several open questions remain about the impact of nanomaterial production and use on environment and health. Many efforts are currently being made not only to prevent nanotechnologies and nanomaterials from contributing to environmental pollution but also to design nanomaterials to support, control, and protect the environment. This Special Issue aims to cover the recent advances in designing nanostructured films focusing on environmental issues related to their fabrication processes (e.g., low power and low cost technologies, the use of environmentally friendly solvents), their precursors (e.g., waste-recycled, bio-based, biodegradable, and natural materials), their applications (e.g., controlled release of chemicals, mimicking of natural processes, and clean energy conversion and storage), and their use in monitoring environment pollution (e.g., sensors optically- or electrically-sensitive to pollutants)

This comprehensive text provides a basic introduction to the optical properties of polymers, as well as a systematic overview of the latest developments in their nano engineering applications—including L-GRIN lenses, 3D holographic displays, optical gene detection, and more. Covering an increasingly important class of materials relevant not only in academic research but also in industry, this book emphasizes the importance of nano engineering in improving the fundamental optical properties of the functional polymers, elaborating on high-level research while thoroughly explaining the underlying principles.

Sculptured thin films (STFs) are a class of nanoengineered materials with properties that can be designed and realized in a controllable manner using physical vapor deposition. This text, presented as a course at the SPIE Optical Science and Technology Symposium, couples detailed knowledge of thin-film morphology with the optical response characteristics of STF devices. An accompanying CD contains Mathematica programs for use with the presented formalisms. Thus, readers will learn to design and engineer STF materials and devices for future applications, particularly with optical applications. Graduate students in optics and practicing optical engineers will find the text valuable, as well as those interested in emerging nanotechnologies for optical devices.

Der Herausgeber ist ein bekannter Pionier des Fachgebiets mit über 30 Jahren Erfahrung. Dieses Handbuch bietet einen umfassenden Überblick über transparente leitfähige Materialien und legt dabei den Schwerpunkt auf praktische Anwendungen. Nach einer Einführung in die Materialien und jüngsten Entwicklungen werden die Synthese und Charakterisierung sowie Beschichtungsverfahren erläutert, die für die Energiegewinnung und bei lichtemittierenden Anwendungen häufig zum Einsatz kommen. Zukünftige technologische Fortschritte werden am Ende des Buches erörtert. Dieses umfassende und aktuelle interdisziplinäre Fachbuch deckt das komplette Spektrum ab, von der Chemie und den Materialwissenschaften zum Ingenieurswesen, von Lehre und Forschung bis zur Industrie, von den grundlegenden Herausforderungen hin zu direkt verfügbaren Anwendungen.