Polymers as Electronic Materials

POLYMERS AS ELECTRONIC MATERIALS - TODAY S POSSIBILITIES AND TOMORROW S DREAMS ... 

Q. Pei and Y. Yang, 1,3,4-Oxadiazole-containing polymers as electron-injection and blue electroluminescent materials in polymer light-emitting diodes, Chem. Mater., 7 1568-1575, 1995. 

In recent several years, super-capacitors are attracting more and more attention because of their high capacitance and potential applications in electronic devices. The performance of super-capacitors with MWCNTs deposited with conducting polymers as active materials is greatly enhanced compared to electric double-layer super-capacitors with CNTs due to the Faraday effect of the conducting polymer as shown in Fig. 9.18 (Valter et al., 2002). Besides those mentioned above, polymer/ CNT nanocomposites own many potential applications (Breuer and Sundararaj, 2004) in electrochemical actuation, wave absorption, electronic packaging, selfregulating heater, and PTC resistors, etc. The conductivity results for polymer/CNT composites are summarized in Table 9.1 (Biercuk et al., 2002). 

In electrochemical light-emitting cells, the semiconductive polymer can be surrounded asymmetrically with a hole-injecting material on one side and a low work function electron injecting metal (such as magnesium, calcium, or aluminum) on the other side. The emission of light may occur when a charge carrier recombines in the polymer as electrons from one side and holes from the other meet. 

What is exactly the impact of this plural materials in opposition to the single material which was said to mark an epoch in the age of iron or in the plastics era Is it possible to set up a consistent research field including such diverse subjects as metals, wood, concrete, ceramics, polymers, and electronic materials How does this field relate to traditional disciplines such as physics and chemistry ... 

Several organics, e.g. pristine poly(3-octylthiophene), polyfluorene, bifunctional spiro compounds and polyphenyleneethynylene derivative, have been used for fabricating photOFETs. Responsivity as high as 0.5-1 A/W has been achieved in some of these transistors. We have already discussed the bulk heterojunction concept in Chapter 5. The bulk heterojunctions are fabricated using acceptor materials with high electron affinity (such as C<5o or soluble derivatives of C6o) mixed with conjugated polymers as electron donors. PhotOFETs based on conjugated polymer/fullerene blends are expected to show... 

For example, when we consider the design of specialty chemical, polymer, biological, electronic materials, etc. processes, the separation units are usually described by transport-limited models, rather than the thermodynamically limited models encountered in petrochemical processes (flash drums, plate distillations, plate absorbers, extractions, etc.). Thus, from a design perspective, we need to estimate vapor-liquid-solid equilibria, as well as transport coefficients. Similarly, we need to estimate reaction kinetic models for all kinds of reactors, for example, chemical, polymer, biological, and electronic materials reactors, as well as crystallization kinetics, based on the molecular structures of the components present. Furthermore, it will be necessary to estimate constitutive equations for the complex materials we will encounter in new processes. 

The increasing demand for thermally stable polymers as electronic encapsulants is consistently creating a need for more information on such materials. Thermogravimetric analysis (TGA) is a valuable tool for the thermal analysis of the silicone polymers. 

Recently, there has been a great deal of Interest In semiconducting organic polymers, particularly polyacetylene ((CH) ), as electronic materials for applications where low cost and large area are important. This report first discusses the potential of organic polymer semiconductors to meet the electronic, physical and economic constraints Imposed by the photovoltaic application. Then, recent results on the structural, electrical, and optical properties of one candidate material, polyacrylonitrile (PAN), are presented. Areas for further Investigation are Indicated. 

It is useful to senior scientists such as faculty members and senior engineers at industry, and it will be particularly useful to junior scientists and newcomers such as postdoctoral fellows, graduate students, and undergraduate students to learn the basic knowledge on polymers and electronic materials and devices. We sincerely hope that these young scientists can find new ideas and opportunities from the introduced areas in this book. Limited by our experience and ability, there may be many imperfections and omissions in this book. We will greatly appreciate critical and suggestive comments from the readers. 

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