Photophysics of Conjugated Polymers

Photophysics of Conjugated Polymers
Author: Tieneke E. Dykstra
Publisher:
Total Pages: 326
Release: 2008
Genre:
ISBN: 9780494578650

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Poly (para-phenylenevinylene) (PPV), and its derivatives such as poly [2-methoxy, 5-(2'-ethyl-hexoxy)-1,4-phenylene vinylene] (MEH-PPV), are typical conjugated polymers. In order to implement conjugated polymers into processable electronics technologies, we must first understand their complex photophysical properties as their efficiencies depend on the balance between exciton recombination and charge carrier formation. The inherent complexities of these materials arise from entanglement of the pi-electron system with disorder and nuclear motions of the polymer backbone. This disorder breaks the polymer chain into conformational subunits which can couple, giving rise to a set of delocalized states formed by Coulombic interactions between proximate subunits. Characteristics of PPVs include high quantum yields, non-mirror image absorption and fluorescence line shapes, and large apparent Stokes' shifts. These properties are discussed in the context of the relationships between polymer conformation, electronic structure, coupling, disorder and polymer photophysics.These important influences are often manifest in the dynamics of what happens after photoexcitation. In this work, we present 3-pulse photon echo peak shift (3PEPS) studies of conjugated polymers in both solution and film. To elucidate timescales characteristic of relaxation processes, we have simulated the 3PEPS data simultaneously with absorption and fluorescence, observing a rapid localization of the exciton in the initial ∼ 20 fs. Additional contributions to the decay of the peakshift are discussed. We also present transient anisotropy data for PPV polymers and oligomers which is compared to dynamics simulation for isolated chains of PPVs. This work demonstrates the influence of microscopic structure on ultrafast dynamics. We show that relaxation between exciton states can lead to rapid depolarization of the anisotropy, even though the spatial extent of exciton migration may be small. Generally, the connection between conformation and electronic structure is a theme throughout this thesis.

Photophysical Studies of Pi-conjugated Oligomers and Polymers That Incorporate Inorganic MLCT Chromophores

Photophysical Studies of Pi-conjugated Oligomers and Polymers That Incorporate Inorganic MLCT Chromophores
Author: Keith Walters
Publisher:
Total Pages: 272
Release: 2019-05-31
Genre: Science
ISBN: 9780530004112

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Abstract: The photophysics and photochemistry of several molecular series incorporating inorganic MLCT chromophores within pi-conjugated oligomers and polymers is presented, including photothermal measurements to determine nonradiative decay rates. Dissertation Discovery Company and University of Florida are dedicated to making scholarly works more discoverable and accessible throughout the world. This dissertation, "Photophysical Studies of Pi-conjugated Oligomers and Polymers That Incorporate Inorganic MLCT Chromophores" by Keith A. Walters, was obtained from University of Florida and is being sold with permission from the author. A digital copy of this work may also be found in the university's institutional repository, IR@UF. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation.

Semiconducting Polymers

Semiconducting Polymers
Author: Raquel Aparecida Domingues
Publisher: CRC Press
Total Pages: 225
Release: 2021-06-25
Genre: Science
ISBN: 1000727963

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Semiconducting polymers are of great interest for applications in electroluminescent devices, solar cells, batteries, and diodes. This volume provides a thorough introduction to the basic concepts of the photophysics of semiconducting polymers as well as a description of the principal polymerization methods for luminescent polymers. Divided into two main sections, the book first introduces the advances made in polymer synthesis and then goes on to focus on the photophysics aspects, also exploring how new advances in the area of controlled syntheses of semiconducting polymers are applied. An understanding of the photophysics process in this kind of material requires some knowledge of many different terms in this field, so a chapter on the basic concepts is included. The process that occurs in semiconducting polymers spans time scales that are unimaginably fast, sometimes less than a picosecond. To appreciate this extraordinary scale, it is necessary to learn a range of vocabularies and concepts that stretch from the basic concepts of photophysics to modern applications, such as electroluminescent devices, solar cells, batteries, and diodes. This book provides a starting point for a broadly based understanding of photophysics concepts applied in understanding semiconducting polymers, incorporating critical ideas from across the scientific spectrum.

Conjugated Polymers And Oligomers: Structural And Soft Matter Aspects

Conjugated Polymers And Oligomers: Structural And Soft Matter Aspects
Author: Matti Knaapila
Publisher: World Scientific
Total Pages: 204
Release: 2017-12-12
Genre: Science
ISBN: 9813225777

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This book identifies modern topics and current trends of structural and soft matter aspects of conjugated polymers and oligomers. Each chapter recognizes an active research line where structural perspective dominates research and therefore the book covers fundamental aspects of persistent conjugated polymer backbone, water soluble conjugated polyelectrolytes and surfactants, conjugated molecules and biomolecules and DNA and the advanced use of synchrotron radiation and electron microscopy to find out structural details in conjugated molecule films and devices as well as under ambient and extreme conditions.

Photophysics of Molecular Materials

Photophysics of Molecular Materials
Author: Guglielmo Lanzani
Publisher: John Wiley & Sons
Total Pages: 600
Release: 2006-05-12
Genre: Science
ISBN: 3527607390

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Carbon based pi-conjugated materials offer a broad range of applications, going from molecular electronics and single molecule devices to nanotechnology, plastic electronics and optoelectronics. The proper physical description of such materials is in between that of molecular solids and that of low-dimensional covalent semiconductors. This book is a comprehensive review of their elementary excitations processes and dynamics, which merges the two viewpoints, sometimes very different if not contrasting. In each chapter, a broad tutorial introduction provides a solid physical background to the topic, which is further discussed based on recent experimental results obtained via state-of-the-art techniques. Both the molecular, intra-chain character and the solid state, inter-molecular physics is addressed. Reports on single molecule and single polymer chain spectroscopy introduce the on-site phenomena. Several chapters are dedicated to nano-probes, steady state and transient spectroscopies. The highly ordered state, occurring in single crystals, is also discussed thoroughly. Finally, less conventional tools such as THz spectroscopy are discussed in detail. The book provides a useful introduction to the field for newcomers, and a valid reference for experienced researchers in the field.

Polyfluorenes

Polyfluorenes
Author: Ullrich Scherf
Publisher: Springer Science & Business Media
Total Pages: 331
Release: 2008-07-29
Genre: Technology & Engineering
ISBN: 3540687335

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With this collection of short review papers we would like to present a broad overview of research on poly?uorenes and related heteroanalogues over the last two decades. The collection begins with papers on the synthesis of po- ?uorenesandrelatedpolyheteroarenes, thenreportsphotophysicalproperties of this class of conjugated polymers both at the ensemble and the single chain level, continues with a discussion of the rich solid state structures of poly?uorenes, and ?nally switches to device applications (e.g. in OLEDs). In addition, two chapters are devoted to de?ned oligo?uorenesas lowmolecular weight model systems forpoly?uorenes and also to degradation studies. We feel that this up-to-date collection will be very helpful to all polymer chemists and physicists, and will also aid graduate students interested in this fascinating and still growing area of research, since such a compact overview is only now available. All articles are presented by leading scientists in their ?elds, insuring state-of-the-art coverage of all relevant aspects. Together with the body of references this volume is meant to assist researchers in the daily lab routine. Moreover, Advances in Polymer Science, as an established series of high quality review papers, represents a very appropriate platform for our project.Wehopethatthisshortcollectionwillbeofgreatvaluebothforbeg- ners and established researchscientists inthe?eldofpoly?uorene research.