Opto-electronic polymers

In this chapter we consider the properties of synthetic polymers. First, the main techniques of polymer synthesis are outlined (Section 2.2). Then the conformation of polymer molecules is discussed in Section 2.3. We move on to a summary of the main methods for characterization of polymeric materials in Section 2.4. Then the distinct features of the main classes of polymer are considered, i.e. solutions (Section 2.5), melts (and glasses) (Section 2.6) and crystals (Section 2.7). Then the important properties of plastics (Section 2.8), rubber (Section 2.9) and polymer fibres (Section 2.10) are related to microscopic structure and to rheology. Polymer blends and block copolymers form varied structures due to phase separation, and this is compared and contrasted for the two types of system in Section 2.11. Section 2.12 is concerned with dendrimers and hyperbranched polymers. Section 2.13 and 2.14 deal with polyelectrolytes and (opto)electronic polymers respectively. 

The science and technology of conducting polymers are inherently interdisciplinary they fall at the intersection of three established disciplines chemistry, physics and engineering hence the name for this volume. These macromolccular materials are synthesized by the methods of organic chemistry. Their electronic structure and electronic properties fall within the domain of condensed matter physics. Efficient processing of conjugated polymer materials into useful forms and the fabrication of electronic and opto-electronic devices require input from engineering i. e. materials science (more specifically, polymer science) and device physics. 

M. Gnyba, M. Keranen, A. Maaninen, J. Suhonen, M. Jedrzejewska-Szczerska, B.B. Kosmowski and R Wierzba, Raman system for on-line monitoring and optimisation of hybrid polymer gelation, Opto-Electron. Rev., 13, 9-17... 

The examples of polyacetylenes whose main chain is directly bonded to heteroaromatic rings (e.g., silole, carbazole, imidazole, tetrathiafulvalene, ferrocene) are increasing in number. Such polymers are usually obtained by one of catalysts (W, Mo, and Rh). The formed polymers are expected to display interesting (opto)electronic properties such as electrochromism, cyclic voltammetry, electroluminescence, and so on. 

SOURCE Reprinted from de Boer, B., U. Stalmach, P. F. van Hutten, C. Melzer, V.V. Krasnikov, and G. Hadziioannou. 2001. Supramolecular self-assembly and opto-electronic properties of semiconducting block copolymers. Polymer 42 9097-9109. Copyright 2001 with permission from Elsevier. 

Applications of conjugated polymers-NCs hybrids in various (opto-)electronic devices and sensors require a deeper understanding of the relationship between their chemical and photophysical properties and their structure at different levels from the molecular to the bulk material. This requires the use of complementary methods... 

Optical Materials. The polyphosphazene skeleton is electron-rich, which means that it provides a refractive index increment compared to conventional saturated organic backbones. In addition, the macromolecular substitution synthesis aUows highly unsaturated organic side groups to be linked to the skeleton in ways that allow the refractive index, the color, the liquid crystalline, and nonlinear optical characteristics of the polymer to be finely tuned. Thus, the use of these polymers in opto-electronic (photonic) switches and lens systems is a subject of growing interest. 

Supramolecular self-assembly and opto-electronic properties of semiconducting block copolymers. Polymer 42 9097... 

From Table 2.3, which lists typical // values, it can be seen that the hole mobility in conjugated polymers is lower than that in organic crystals and amorphous silicon, but much larger than that in undoped poly(N-vinyl carbazole). Therefore, conjugated polymers have potential for applications in conducting opto-electronic and photonic devices. In principle, this also applies to liquid-crystal systems that can exhibit enhanced molecular order due to their self-organizing ability, as has been pointed out in a progress report [42]. 

Keio University, 16,47, 58 Kent State University, 507 Kyoto Institute of Technology, 151 Kyoto University, 460 Massachusetts Institute of Technology, 437 Max Planck Institute for Polymer Research, 100, 358 National Taiwan University, 71 NTT Opto-electronics Laboratories, 30 Ohio State University, 395 Queen s University, 236 Royal Military College, 236 State University of New York at Buffalo, 533... 

When a polymer solution is allowed to evaporate from a surface, dewetting instabilities can arise, producing modulated patterns like spinodal structures (68). Section IV addresses the applicability of these interesting phenomena to making opto-electronical devices. 

M. Inoue, H. Monobe, M. Ukon, V.F. Petrov, T. Watanabe, A. Kumano, Y. Shimizu, Fast charged carrier mobility of a triphenylene-based polymer film possessing nematic order. Opto-Electron. Rev. 13, 303-308 (2005)... 

Moreover, some investigations have dealt with the combination of the photonic properties and the ordered porous structure for light-harvesting or emitting. In both cases, light-sensitive honeycomb films based on semi-conductive NPs or conjugated polymers were used to improve the opto-electronic properties of organic thin-film devices [126, 161, 174,176, 190-192]. 

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