Download or read book Understanding Microstructure and Charge Transport in Semicrystalline Polythiophenes written by Leslie Hendrix Jimison and published by Stanford University. This book was released on 2011 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiconducting polymers are a promising class of organic electronic materials, with the potential to have a large impact in the field of macroelectronics. In this thesis, we focus on understanding the relationship between microstructure and charge transport in semicrystalline polythiophenes. A method is presented for the measurement of complete pole figures of polymer thin films using an area detector, allowing for the first time quantitative characterization of crystalline texture and degree of crystallinity. Thin film transistors are used to measure electrical characteristics, and charge transport behavior is modeled according to the Mobility Edge (ME) model. These characterization methods are first used to investigate the effect of substrate surface treatment and thermal annealing on the microstructure of polythiophene thin films, and the effect of microstructural details on charge transport. Next, we investigate the semicrystalline microstructure in confined polythiophene films. Pole figures are used to quantify a decrease in the degree of crystallinity of films with decreasing thickness, accompanied by an improvement in crystalline texture. Next, we investigate the influence of the degree of regioregularity, molecular weight and the processing solvent on microstructure (degree of crystallinity and texture) and charge transport in high mobility P3HT thin films. Surprisingly, when processing conditions are optimized, even a polymer with moderate regioregularity can form a highly textured film with high charge carrier mobility. Finally, we use films of P3HT with engineered, anisotropic in-plane microstructure to understand the importance and mechanism of transport across grain boundaries in these semicrystalline films. Results from this study provide the first experimental evidence for the application of a percolation model for charge transport in high molecular weight semicrystalline polymer semiconductors. Understanding how characteristics of the polymer as well as details of the processing conditions can affect the film microstructure and device performance is important for future materials design and device fabrication.
Download or read book Understanding Microstructure and Charge Transport in Semicrystalline Polythiophenes written by Leslie Hendrix Jimison and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiconducting polymers are a promising class of organic electronic materials, with the potential to have a large impact in the field of macroelectronics. In this thesis, we focus on understanding the relationship between microstructure and charge transport in semicrystalline polythiophenes. A method is presented for the measurement of complete pole figures of polymer thin films using an area detector, allowing for the first time quantitative characterization of crystalline texture and degree of crystallinity. Thin film transistors are used to measure electrical characteristics, and charge transport behavior is modeled according to the Mobility Edge (ME) model. These characterization methods are first used to investigate the effect of substrate surface treatment and thermal annealing on the microstructure of polythiophene thin films, and the effect of microstructural details on charge transport. Next, we investigate the semicrystalline microstructure in confined polythiophene films. Pole figures are used to quantify a decrease in the degree of crystallinity of films with decreasing thickness, accompanied by an improvement in crystalline texture. Next, we investigate the influence of the degree of regioregularity, molecular weight and the processing solvent on microstructure (degree of crystallinity and texture) and charge transport in high mobility P3HT thin films. Surprisingly, when processing conditions are optimized, even a polymer with moderate regioregularity can form a highly textured film with high charge carrier mobility. Finally, we use films of P3HT with engineered, anisotropic in-plane microstructure to understand the importance and mechanism of transport across grain boundaries in these semicrystalline films. Results from this study provide the first experimental evidence for the application of a percolation model for charge transport in high molecular weight semicrystalline polymer semiconductors. Understanding how characteristics of the polymer as well as details of the processing conditions can affect the film microstructure and device performance is important for future materials design and device fabrication.
Download or read book Charge Transport in Semiconducting Polymers written by Scott Himmelberger and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic semiconductors have emerged as an alternative to conventional silicon-based electronics in a number of large-area applications including lighting, displays, and sensors. Their ease of processing and compatibility with solution-based deposition techniques makes them attractive for low-cost, roll-to-roll production processes. However, despite significant progress in recent years, the electronic performance of these materials remains modest relative to silicon, limiting their potential applications. In order for organic semiconductors to truly flourish in industry, electronic figures of merit such as charge carrier mobility must be improved further. The material microstructure is one of the key determinants of charge carrier mobility in organic semiconductors. While many new microstructure characterization tools have been developed and our understanding of the relationship between microstructure and electronic properties has greatly improved, significant questions remain, limiting our ability to rationally design and process new materials with improved performance. The focus of this dissertation has been in attempting to improve this understanding. In this dissertation, I discuss several ways in which the microstructure of semiconducting polymers affects their electronic properties. First, I present a procedure for determining the precise thin-film structure of a semiconducting polymer using two-dimensional grazing incidence X-ray diffraction. These packing structures can then be used in a variety of electronic structure calculations. Next, I discuss the role of molecular weight distribution as well as the impact of film confinement on the microstructure and electronic properties of two semicrystalline polythiophenes. I show how disorder, crystallinity, and chain orientation are strongly influenced by these factors and quantify their impact on charge carrier mobility. Finally, I describe our latest understanding of the factors governing charge transport in state-of-the-art materials. I suggest that disorder is an inextricable feature of semiconducting polymers that need not be highly detrimental to charge transport if it is embraced and planned for by designing materials which are resilient to this disorder.
Download or read book Understanding the Impact of Polymer Self organization on the Microstructure and Charge Transport in Poly 3 hexylthiophene written by Avishek R. Aiyar and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Microstructure and Charge Transport in Conjugated Polymers written by Chenchen Wang and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Conjugated polymers have attracted broad interest in the past few decades due to their potential applications in organic light emitting diodes, low-cost flexible circuits, biosensors and photovoltaics. Because of their semicrystalline nature, the spatial arrangement of the crystallites and the disordered regions would have strong impact on the charge transport properties of conjugated polymer thin films. Therefore, in this presentation, I will focus on understanding the relationship between the film's morphology, microstructure and electronic properties, and how to fabricate desired structure to achieve devices with novel electronic performance. In the first part of the presentation, I will show that the device's electronic performance can be greatly improved by engineering its structure in solution based fabrication process. The binary blends of regioregular (rr) and regiorandom (RRa) P3HT are used to form desired FET structures. X-ray diffraction of the blended films is consistent with a vertically-separated structure, with rr-P3HT preferentially crystallizing at the semiconductor/dielectric interface. Because of the ultra-thin rr-P3HT active layer at the interface, these devices not only preserve high mobility in rr-P3HT, but also eliminate the short channel effects due to bulk currents, suggesting a new route to fabricate high performance, short-channel and reliable organic electronic devices. After that, I will discuss the microstructural origin of high mobility in poly(2,5-bis(3-alkylthiophen-2-yl)thieno[3,2-b]thiophenes) (PBTTT) thin-film transistors (TFTs). Charge transport in PBTTT TFTs is analyzed with a mobility edge (ME) model and compared to these in poly(3-hexylthiophene) (P3HT) TFTs. With TEM characterization of delaminated films, we conclude that the improved performance of PBTTT compared to P3HT is not due to a low trap density but rather to a high mobility in the crystallites. Finally, the third part of the presentation will focus on optical characterization of doping in conjugated polymers. UV-vis and IR absorption spectra of 2,3,5,6-Tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) doped P3HT at different doping concentration are measured and analyzed. Absorption peaks from P3HT, F4TCNQ, F4TCNQ anion and P3HT polaron/bipolarons are identified and decomposed. The P3HT polaron/bipolarons cross sections in UV-vis region are estimated, which can be used to evaluate doping efficiency in this material.
Download or read book Chain Conformation and Disorder in High Mobility Semiconducting Polymers written by Rodrigo Javier Noriega-Manez and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A critical step to understanding charge transport in complex systems is being able to characterize them accurately and extensively. In particular, the microstucture of conjugated polymers exhibits a coexistence of ordered and amorphous regions, with the size of the ordered regions being smaller than the length of individual polymer chains. In order to study the ordered regions we use advanced X-ray diffraction analysis in combination with computational modeling and measurements of optical and electrical properties. It was possible to uncover fundamental relationships between short-range order in pi-aggregates, aggregate connectivity and macroscopic charge transport in semiconducting polymers. An unusually high and materials-independent amount of paracrystalline disorder was found in all high-performing polymers. Computer simulations and analytical models made the connection between fluctuations in molecular arrangement and electronic traps. Charge transport studies elucidated the predominant role of paracrystallites in semicrystalline and strongly disordered polymer films. The other component of the microstructure -- the amorphous regions -- deserves our attention as well since aggregate connectivity depends on it. A model for charge transport in strongly disordered polymers was developed for this reason. The morphology of individual polymer chains can be determined by well-known statistical models. Likewise, the electronic coupling between units along a polymer chain and on different molecules can be determined by Marcus theory. Combining knowledge from both areas into an analytical and computational model that incorporates the structural and electronic properties of polymers, it is possible to explain observations that previously relied on phenomenological models. The multi-scale behavior of charges in these materials (high mobility at short scales, low mobility at long scales) is naturally described with this framework. Additionally, the dependence of mobility with electric field and temperature is explained in terms of conformational fluctuations and correlations. Bringing all these concepts together it is possible to provide a more complete description of the way in which charges move in conjugated polymers, a set of materials that occupies an intermediate region between ordered and disordered systems, with a great amount of complexity at various length scales. Doing so will facilitate the feedback cycle between molecular design, microstructure optimization, and device performance.
Download or read book Organic Flexible Electronics written by Piero Cosseddu and published by Woodhead Publishing. This book was released on 2020-09-29 with total page 666 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic Electronics is a novel field of electronics that has gained an incredible attention over the past few decades. New materials, device architectures and applications have been continuously introduced by the academic and also industrial communities, and novel topics have raised strong interest in such communities, as molecular doping, thermoelectrics, bioelectronics and many others.Organic Flexible Electronics is mainly divided into three sections. The first part is focused on the fundamentals of organic electronics, such as charge transport models in these systems and new approaches for the design and synthesis of novel molecules. The first section addresses the main challenges that are still open in this field, including the important role of interfaces for achieving high-performing devices or the novel approaches employed for improving reliability issues.The second part discusses the most innovative devices which have been developed in recent years, such as devices for energy harvesting, flexible batteries, high frequency circuits, and flexible devices for tattoo electronics and bioelectronics.Finally the book reviews the most important applications moving from more standard flexible back panels to wearable and textile electronics and more futuristic applications like ingestible systems. Reviews the fundamental properties and methods for optimizing organic electronic materials including chemical doping and techniques to address stability issues Discusses the most promising organic electronic devices for energy, electronics, and biomedical applications Addresses key applications of organic electronic devices in imagers, wearable electronics, bioelectronics
Download or read book Understanding Morphology and Anisotropic Charge Transport in Conjugated Semi crystalline Polymers written by Kim Tremel and published by . This book was released on 2014 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Handbook of Conducting Polymers Fourth Edition 2 Volume Set written by John R. Reynolds and published by CRC Press. This book was released on 2019-11-14 with total page 1488 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last 10 years there have been major advances in fundamental understanding and applications and a vast portfolio of new polymer structures with unique and tailored properties was developed. Work moved from a chemical repeat unit structure to one more based on structural control, new polymerization methodologies, properties, processing, and applications. The 4th Edition takes this into account and will be completely rewritten and reorganized, focusing on spin coating, spray coating, blade/slot die coating, layer-by-layer assembly, and fiber spinning methods; property characterizations of redox, interfacial, electrical, and optical phenomena; and commercial applications.
Download or read book Conjugated Polymers written by John R. Reynolds and published by CRC Press. This book was released on 2019-03-25 with total page 832 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers properties, processing, and applications of conducting polymers. It discusses properties and characterization, including photophysics and transport. It then moves to processing and morphology of conducting polymers, covering such topics as printing, thermal processing, morphology evolution, conducting polymer composites, thin films
Download or read book On the Ordering Microstructure and Hole Transport Correlations in Semi crystalline Poly 3 hexylthiophene written by Xiaobo Shen and published by . This book was released on 2015 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Heterocyclic Chemistry written by and published by Academic Press. This book was released on 2015-08-12 with total page 387 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Heterocyclic Chemistry is the definitive series in the field—one of great importance to organic chemists, polymer chemists, and many biological scientists. Because biology and organic chemistry increasingly intersect, the associated nomenclature also is being used more frequently in explanations. Written by established authorities in the field from around the world, this comprehensive review combines descriptive synthetic chemistry and mechanistic insight to yield an understanding of how chemistry drives the preparation and useful properties of heterocyclic compounds. Considered the definitive serial in the field of heterocyclic chemistry Serves as the go-to reference for organic chemists, polymer chemists, and many biological scientists Provides the latest comprehensive reviews written by established authorities in the field Combines descriptive synthetic chemistry and mechanistic insight to enhance understanding of how chemistry drives the preparation and useful properties of heterocyclic compounds
Download or read book Structure function Relationships in Semiconducting Polymers written by Luke Balhorn and published by . This book was released on 2022 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Improving knowledge of structure-function relationships in semiconducting polymers will help design new materials that unlock new applications. This work harnesses recent advances in transmission electron microscopy of soft materials to study length scales of microstructure in these materials that have previously been difficult to probe. Further, it combines electron microscopy with structural and charge transport simulations to study the effects of mesoscale defects on charge transport in highly ordered semicrystalline polymers. Spatially resolved nanodiffraction (4D-STEM) is used to create maps of chain direction and local order in conjugated polymers. Simulations are then built upon this experimental map, first by generating molecular geometries consistent with diffraction data, then by tracking the paths of test charges across the region. A case study in this combined method is conducted using the polymer PBTTT. Short-range charge transport is shown to be more chaotic than is often pictured, with the drift velocity accounting for a small portion of overall charge motion. Local transport is sensitive to the alignment and geometry of polymer chains. At longer length scales, the curves of this PBTTT microstructure funnel charges to specific regions, creating inhomogeneous charge distributions. While alignment generally improves mobility, these funneling effects limit the overall efficiency of charge transport. The structure is modified \textit{in silico} to explore possible design rules, showing chain stiffness and alignment to be beneficial while local homogeneity has no positive effect. These observations provide direct guidance for improving mesoscale structure for future materials.
Download or read book P3HT Revisited From Molecular Scale to Solar Cell Devices written by Sabine Ludwigs and published by Springer. This book was released on 2014-11-13 with total page 239 pages. Available in PDF, EPUB and Kindle. Book excerpt: The series Advances in Polymer Science presents critical reviews of the present and future trends in polymer and biopolymer science. It covers all areas of research in polymer and biopolymer science including chemistry, physical chemistry, physics, material science. The thematic volumes are addressed to scientists, whether at universities or in industry, who wish to keep abreast of the important advances in the covered topics. Advances in Polymer Science enjoys a longstanding tradition and good reputation in its community. Each volume is dedicated to a current topic, and each review critically surveys one aspect of that topic, to place it within the context of the volume. The volumes typically summarize the significant developments of the last 5 to 10 years and discuss them critically, presenting selected examples, explaining and illustrating the important principles, and bringing together many important references of primary literature. On that basis, future research directions in the area can be discussed. Advances in Polymer Science volumes thus are important references for every polymer scientist, as well as for other scientists interested in polymer science - as an introduction to a neighboring field, or as a compilation of detailed information for the specialist. Review articles for the individual volumes are invited by the volume editors. Single contributions can be specially commissioned. Readership: Polymer scientists, or scientists in related fields interested in polymer and biopolymer science, at universities or in industry, graduate students
Download or read book Organic Electronics written by Fabio Cicoira and published by John Wiley & Sons. This book was released on 2013-07-17 with total page 441 pages. Available in PDF, EPUB and Kindle. Book excerpt: An overview of the tremendous potential of organic electronics, concentrating on those emerging topics and technologies that will form the focus of research over the next five to ten years. The young and energetic team of editors with an excellent research track record has brought together internationally renowned authors to review up-and-coming topics, some for the first time, such as organic spintronics, iontronics, light emitting transistors, organic sensors and advanced structural analysis. As a result, this book serves the needs of experienced researchers in organic electronics, graduate students and post-doctoral researchers, as well as scientists active in closely related fields, including organic chemical synthesis, thin film growth and biomaterials. Cover Figure: With kind permission of Matitaccia.
Download or read book Conducting Polymers written by Ram K. Gupta and published by CRC Press. This book was released on 2022-04-19 with total page 439 pages. Available in PDF, EPUB and Kindle. Book excerpt: Conducting polymers are versatile materials that possess both the unique properties of polymeric materials (elastic behavior, reversible deformation, flexibility, etc.) and the ability to conduct electricity with bulk conductivities comparable to those of metals and semiconductors. Conducting Polymers: Chemistries, Properties and Biomedical Applications provides current, state-of-the-art knowledge of conducting polymers and their composites for biomedical applications. This book covers the fundamentals of conducting polymers, strategies to modify the structure of conducting polymers to make them biocompatible, and their applications in various biomedical areas such as drug/gene delivery, tissue engineering, antimicrobial activities, biosensors, etc. FEATURES Covers the state-of-the-art progress on biodegradable conducting polymers for biomedical applications Presents synthesis, characterization, and applications of conducting polymers for various biomedical research Provides the fundamentals of biodegradation mechanisms and the role of conduction in biomedical devices Offers details of novel methods and advanced technologies used in biomedical applications using conducting polymers Highlights new directions for scientists, researchers, and students to better understand the chemistry, technologies, and applications of conducting polymers This book is essential reading for all academic and industrial researchers working in the fields of materials science, polymers, nanotechnology, and biomedical technology.
Download or read book Polymer Electronics written by Mark Geoghegan and published by OUP Oxford. This book was released on 2013-04-04 with total page 271 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymer electronics is the science behind many important new developments in technology, such as the flexible electronic display (e-ink) and many new developments in transistor technology. Solar cells, light-emitting diodes, and transistors are all areas where plastic electronics is likely to, or is already having, a serious impact on our daily lives. With polymer transistors and light-emitting diodes now being commercialised, there is a clear need for a pedagogic text that discusses the subject in a clear and concise fashion suitable for senior undergraduate and graduate students. The content builds on what has been learnt in an elementary (core) course in solid state physics and electronic behaviour, but care has been taken to ensure that important aspects such as the synthesis of these polymers are not overlooked. The chemistry is treated in a manner appropriate to students of physics. Polymer Electronics presents a thorough discussion of the physics and chemistry behind this new and important area of science, appealing to all physical scientists with an interest in the field.
