The Electronic And Optical Properties Of Conjugated Polymers

Conjugated polymers have important technological applications, including solar cells and light emitting devices. They are also active components in many important biological processes. In recent years there have been significant advances in our understanding of these systems, owing to both improved experimental measurements and the development of advanced computational techniques. The aim of this book is to describe and explain the electronic and optical properties of conjugated polymers. It focuses on the three key roles of electron-electron interactions, electron-nuclear coupling, and disorder in determining the character of the electronic states, and it relates these properties to experimental observations in real systems. A number of important optical and electronic processes in conjugated polymers are also described. The second edition has a more extended discussion of excitons in conjugated polymers. There is also a new chapter on the static and dynamical localization of excitons.

Conjugated polymers have important technological applications including solar cells and light emitting devices. They are active components in many important biological processes. This book describes and explains the electronic and optical properties of conjugated polymers by developing theoretical models to understand the key electronic states.

This book constitutes the Proceedings of the NATO Advanced Research Workshop on Conjugated Polymers held at the University of Mons, Belgium, during the first week of September 1989. The Workshop was attended by about fifty scientists representing most of the leading research groups within NATO countries, that have contributed to the development of conjugated polymeric materials. The program was focused on applications related to electrical conductivity and nonlinear optics. The attendance was well balanced with a blend of researchers from academic, industrial, and government labs, and including synthetic chemists, physical chemists, physicists, materials scientists, and theoreticians. The Workshop provided an especially timely opportunity to discuss the important progress that has taken place in the field of Conjugated Polymers in the late eighties as well as the enormous potential that lies in front of us. Among the recent significant developments in the field, we can cite for instance: (i) The discovery of novel synthetic routes affording conjugated polymers -that are much better characterized, especially through control of the molecular weight; - that can be processed from solution or the melt; the early promise that conducting polymcrs would constitute materials combining the electrical conductivities of metals with the mechanical properties of plastics is now being realized; -that can reach remarkably high conductivities.

This book deals with electrical, electrochemical, structural, magnetic, optical and lattice dynamical properties of conjugated polymers such as polyaniline, polyacetylene, polydiacetylene, polypyrrole, polyparaphenylene and polythiophene. Several new conjugated systems and model polyenes are also considered. Since the previous winter school on this topic held in 1985, the focus of interest in the field has broadened and now covers not only conductivity and relaxation phenomena of polyacetylene but also nonlinear optical properties, highly oriented and single crystal polymers, and electrochemical and opto-electrochemical properties of special materials. Particular attention is paid in this volume to the possible applications of these systems, for example, in electrochemical cells as electrode materials and in nonlinear optics devices, which now appear to be much more realistic than previously. The detailed contributions are complemented by short reviews of thin film polymers (Langmuir-Blodgett layers), filled polymers, ferromagnetic polymers, superconducting low-dimensional systems (including organic superconductors and high-temperature superconductors) and the application of fractal models to polymers.

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.

This book is intended for those who are interested in understanding the electronic structure and properties of polymers. The scope of the book is to provide the non-specialist reader with a comprehensive and unified description: (i) of quantum mechanical methods, mainly originating from quantum chemistry, to calculate the electronic properties of polymers, (ii) of their use for interpreting and predicting results in fields where the electronic structure is playing an important role, like the electrical conductivity and the non linear optical properties of conjugated polymers. It will also serve as a reference book to lecture graduate students on the electronic structure of polymers or more generally of quasi-one dimensional materials. In this framework, it is worth stressing that the quantum theory of polymers bridges the gap between chemistry and physics. Since no book of this kind involving a strong interaction between theoretical and experimental concepts is available at the moment, it will also meet a need for a timely monograph in a field of important and fast growing interest. Contents:The Band Theory of PolymersThe Computational Machinery of Band Theory of PolymersQuantum Approach to Electrical Conduction Phenomena in Conjugated Organic PolymersQuantum Chemistry Aided Design of Chains for Optoelectronics Readership: Theoretical chemists, physicists, materials scientists, solid state physicists, condensed matter physicists and physical chemists. Keywords:Quantum Chemistry;Polymers;Ab Initio Calculations;Novel Materials;Conducting Polymers;Semiconducting Polymers;Nonlinear Optics;Electron Spectroscopy;Organic Solid State;Electronic Structure of Polymers;Conjugated Polymers;Ab Initio Methods;Semiempirical Methods;Band Structure Calculations;Valence Effective Hamiltonian MethodReview: “… offers a good review of quantum mechanics as applied to the study of the electronic and optical properties of polymers … the discussions are clear and concise and easily understood. As high-performance computers become more available, calculations of the type described in this book will become an integral part of advanced materials research.” American Scientist

This book brings together selected contributions both on the fundamental information on the physics and chemistry of these materials, new physical ideas and decisive experiments. It constitutes both an insightful treatise and a handy reference for specialists and graduate students working in solid state physics and chemistry, material science and related fields.