Symmetrically configured AC light emitting (SCALE) devices based on conjugated polymers utilizing indium tin oxide (ITO) and aluminum as electrodes have been demonstrated recently. Here we report the fabrication of SCALE devices using a more stable high work function metal, such as gold, as a charge (both electron and hole) injection electrode. Also, a variation of such devices in which the electroluminescent polymer, instead of being separated from the insulating polymer, is dispersed in the insulating polymer to form a unified emitter insulator, is reported. These devices emit light in both forward and reverse DC bias with symmetric current voltage characteristics. Under low frequency AC (sinusoidal) driving voltage, light pulses with double the driving frequency are observed. A model is proposed to account for the device operation.

Electroactive polymers have been the object of increasing academic and industrial interest and in the past ten to fifteen years substantial progress has been achieved in the development and the characterization of this important new class of conducting materials. These materials are usually classified in two large groups, according to the mode of their electric transport. One group includes polymers having transport almost exclusively of the ionic type and they are often called 'polymer electrolytes' or, in a broader way, 'polymer ionics'. The other group includes polymeric materials where the transport mechanism is mainly electronic in nature and which are commonly termed 'conducting polymers'. Ionically conducting polymers or polymer ionics may be typically described as polar macromolecular solids in which one or more of a wide range of salts has been dissolved. The most classic example is the combina tion of poly(ethylene oxide), PEO, and lithium salts, LiX. These PEO-LiX polymer ionics were first described and proposed for applications just over ten years ago. The practical relevance of these new materials was im mediately recognized and in the course of a few years the field expanded tremendously with the involvement of many academic and industrial lab oratories. Following this diversified research activity, the ionic transport mechanism in polymer ionics was soon established and this has led to the development of new host polymers of various types, new salts and advanced polymer architectures which have enabled room temperature conductivity to be raised by several orders of magnitude.

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.

The most recent advances in the use of polymeric materials by the electronic industry can be found in Polymers for Electronic and Photonic Applications. This bookprovides in-depth coverage of photoresis for micro-lithography, microelectronic encapsulants and packaging, insulators, dielectrics for multichip packaging,electronic and photonic applications of polymeric materials, among many other topics. Intended for engineers and scientists who design, process, and manufacturemicroelectronic components, this book will also prove useful for hybrid and systems packaging managers who want to be informed of the very latest developments inthis field. * Presents most recent advances in the use of polymeric materials by the electronic industry* Contributions by foremost experts in the field

The second edition of this popular textbook thoroughly covers the practical basics and applications of conducting polymers. It also addresses materials that have gained prominence since the first edition of this book was published, namely carbon nanotubes and graphene. The features of this new edition include: New and updated chapters on novel concepts in conducting polymers Details on interdisciplinary applications of conducting polymers An in depth description of classes of conducting polymers