Download or read book Enhancing the Efficiency of Organic Semiconductor Materials written by Aijaz Rasool Chaudhry and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigating the Nucleation Growth and Energy Levels of Organic Semiconductors for High Performance Plastic Electronics written by Ajay Virkar and published by Springer Science & Business Media. This book was released on 2011-09-29 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis details the significant progress made in improving the performance of organic transistors and the network conductivity of carbon nanotubes. The first section investigates organic semiconductor nucleation and growth on the most common dielectric surface used to fabricate organic thin film transistors. The nucleation and growth of the semiconductor was determined to be a critical factor affecting the device performance. Excellent dielectric modification layers, which promote desirable semiconductor growth leading to high conductivity were identified, and a technologically relevant deposition technique was developed to fabricate high quality dielectric modification layers over large areas. This may represent an important step towards the realization of large area organic circuity. In the final section, lessons learned from studying organic semiconductor nucleation and growth were utilized to improve the conductivity of carbon nanotube networks. Selective nucleation of materials at the junctions between nanotubes in the network significantly decreased the network's sheet resistance. The resulting networks may be promising candidates for transparent electrodes with a variety of optoelectronic applications.

Download or read book Organic Thin Film Transistor Integration written by Flora Li and published by John Wiley & Sons. This book was released on 2011-03-21 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research on organic electronics (or plastic electronics) is driven by the need to create systems that are lightweight, unbreakable, and mechanically flexible. With the remarkable improvement in the performance of organic semiconductor materials during the past few decades, organic electronics appeal to innovative, practical, and broad-impact applications requiring large-area coverage, mechanical flexibility, low-temperature processing, and low cost. Thus, organic electronics appeal to a broad range of electronic devices and products including transistors, diodes, sensors, solar cells, lighting, displays, and electronic identification and tracking devices A number of commercial opportunities have been identified for organic thin film transistors (OTFTs), ranging from flexible displays, electronic paper, radio-frequency identification (RFID) tags, smart cards, to low-cost disposable electronic products, and more are continually being invented as the technology matures. The potential applications for "plastic electronics" are huge but several technological hurdles must be overcome. In many of these applications, transistor serves as a fundamental building block to implement the necessary electronic functionality. Hence, research in organic thin film transistors (OTFTs) or organic field effect transistors (OFETs) is eminently pertinent to the development and realization of organic electronics. This book presents a comprehensive investigation of the production and application of a variety of polymer based transistor devices and circuits. It begins with a detailed overview of Organic Thin Film Transistors (OTFTs) and discusses the various possible fabrication methods reported so far. This is followed by two major sections on the choice, optimization and implementation of the gate dielectric material to be used. Details of the effects of processing on the efficiency of the contacts are then provided. The book concludes with a chapter on the integration of such devices to produce a variety of OTFT based circuits and systems. The key objective is to examine strategies to exploit existing materials and techniques to advance OTFT technology in device performance, device manufacture, and device integration. Finally, the collective knowledge from these investigations facilitates the integration of OTFTs into organic circuits, which is expected to contribute to the development of new generation of all-organic displays for communication devices and other pertinent applications. Overall, a major outcome of this work is that it provides an economical means for organic transistor and circuit integration, by enabling the use of a well-established PECVD infrastructure, while not compromising the performance of electronics. The techniques established here are not limited to use in OTFTs only; the organic semiconductor and SiNx combination can be used in other device structures (e.g., sensors, diodes, photovoltaics). Furthermore, the approach and strategy used for interface optimization can be extended to the development of other materials systems.

Download or read book Semiconductor Materials and Modelling for Solar Cells written by Z. Pezeshki and published by Materials Research Forum LLC. This book was released on 2021-07-05 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book presents a comprehensive survey about advanced solar cell technologies. Focus is placed on semiconductor materials, solar cell efficiency, improvements in surface recombination velocity, charge density, high ultraviolet (UV) sensitivity, modeling of solar cells etc. The book references 281 original resources with their direct web links for in-depth reading. Keywords: Solar Cells, Thin Film Solar Cells, Solar Cell Efficiency, Semiconductor Materials, Surface Recombination Velocity, Charge Density, High UV Sensitivity, Heavily-doped Silicon Wafers, Amorphous Semiconductors, Nanocrystalline Semiconductors, Field Effect, Ferroelectric Semiconductors, Solar Cell Modelling.

Download or read book Organic Semiconductors for Optoelectronics written by Hiroyoshi Naito and published by John Wiley & Sons. This book was released on 2021-07-30 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprehensive coverage of organic electronics, including fundamental theory, basic properties, characterization methods, device physics, and future trends Organic semiconductor materials have vast commercial potential for a wide range of applications, from self-emitting OLED displays and solid-state lighting to plastic electronics and organic solar cells. As research in organic optoelectronic devices continues to expand at an unprecedented rate, organic semiconductors are being applied to flexible displays, biosensors, and other cost-effective green devices in ways not possible with conventional inorganic semiconductors. Organic Semiconductors for Optoelectronics is an up-to-date review of the both the fundamental theory and latest research and development advances in organic semiconductors. Featuring contributions from an international team of experts, this comprehensive volume covers basic properties of organic semiconductors, characterization techniques, device physics, and future trends in organic device development. Detailed chapters provide key information on the device physics of organic field-effect transistors, organic light-emitting diodes, organic solar cells, organic photosensors, and more. This authoritative resource: Provides a clear understanding of the optoelectronic properties of organic semiconductors and their influence to overall device performance Explains the theories behind relevant mechanisms in organic semiconducting materials and in organic devices Discusses current and future trends and challenges in the development of organic optoelectronic devices Reviews electronic properties, device mechanisms, and characterization techniques of organic semiconducting materials Covers theoretical concepts of optical properties of organic semiconductors including fluorescent, phosphorescent, and thermally-assisted delayed fluorescent emitters An important new addition to the Wiley Series in Materials for Electronic & Optoelectronic Applications, Organic Semiconductors for Optoelectronics bridges the gap between advanced books and undergraduate textbooks on semiconductor physics and solid-state physics. It is essential reading for academic researchers, graduate students, and industry professionals involved in organic electronics, materials science, thin film devices, and optoelectronics research and development.

Download or read book Organic Thermoelectric Materials written by Zhiqun Lin and published by Royal Society of Chemistry. This book was released on 2019-10-18 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book summarises the significant progress made in organic thermoelectric materials, focusing on effective routes to minimize thermal conductivity and maximize power factor.

Download or read book Electronic Processes in Organic Semiconductors written by Anna Köhler and published by John Wiley & Sons. This book was released on 2015-06-08 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first advanced textbook to provide a useful introduction in a brief, coherent and comprehensive way, with a focus on the fundamentals. After having read this book, students will be prepared to understand any of the many multi-authored books available in this field that discuss a particular aspect in more detail, and should also benefit from any of the textbooks in photochemistry or spectroscopy that concentrate on a particular mechanism. Based on a successful and well-proven lecture course given by one of the authors for many years, the book is clearly structured into four sections: electronic structure of organic semiconductors, charged and excited states in organic semiconductors, electronic and optical properties of organic semiconductors, and fundamentals of organic semiconductor devices.

Download or read book Effects of Energetic Disorder on the Optoelectronic Properties of Organic Solar Cells written by Nikolaos Felekidis and published by Linköping University Electronic Press. This book was released on 2018-09-10 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic photovoltaics (OPVs) is a promising low-cost and environmental-friendly technology currently achieving 12-14% power conversion efficiency. Despite the extensive focus of the research community over the last years, critical mechanisms defining the performance of OPVs are still topics of debate. While energetic disorder is known to be characteristic of organic semiconductors in general, its potential role in OPV has received surprisingly little attention. In this thesis we investigate some aspects of the relation between energetic disorder and several optoelectronic properties of OPV. Charge carrier mobility is a key parameter in characterizing the performance of organic semiconductors. Analyzing the temperature dependence of the mobility is also an oftenused method to obtain (estimates for) the energetic disorder in the HOMO and LUMO levels of an organic semiconductor material. Different formalisms to extract and analyze mobilities from space charge limited conductivity (SCLC) experiments are reviewed. Surprisingly, the Murgatroyd-Gill analytical model in combination with the Gaussian disorder model in the Boltzmann limit yields similar mobilities and energetic disorders as a more elaborate drift-diffusion model with parametrized mobility functionals. Common analysis and measurement errors are discussed. All the models are incorporated in an automated analysis freeware tool. The open circuit voltage (Voc) has attracted considerable interest as the large difference between Voc and the bandgap is the main loss mechanism in bulk heterojunction OPVs. Surprisingly, in ternary devices composed of two donors and one acceptor, the Voc is not pinned to the shallowest HOMO but demonstrates a continuous tunability between the binary extremities. We show that this phenomenon can be explained with an equilibrium model where Voc is defined as the splitting of the quasi-Fermi levels of the photo-created holes and electrons in a common density of states accounting for the stoichiometry, i.e. the ratio of the donor materials and the broadening by Gaussian disorder. Evaluating the PCE, it is found that ternary devices do not offer advantages over binary unless the fill factor (FF) is increased at intermediate compositions, as a result of improved transport/recombination upon material blending. Stressing the importance of material intermixing to improve the performance, we found that the presence of an acceptor may drastically alter the mobility and energetic disorder of the donor and vice versa. The effect of different acceptors was studied in a ternary onedonor- two-acceptors system, where the unpredictable variability with composition of the energetic disorder in the HOMO and the LUMO explained the almost linear tunability of Voc. Designing binary OPVs based on the design rule that the energetic disorder can be reduced upon material blending, as we observed, can yield a relative PCE improvement of at least 20%. CT states currently play a key role in evaluating the performance of OPVs and CTelectroluminescence (CT-EL) is assumed to stem from the recombination of thermalized electron-hole pairs. The varying width of the CT-EL peak for different material combinations is intuitively expected to reflect the energetic disorder of the effective HOMO and LUMO. We employ kinetic Monte Carlo (kMC) CT-EL simulations, using independently measured disorder parameters as input, to calculate the ground-to-ground state (0-0) transition spectrum. Including the vibronic broadening according to the Franck Condon principle, we reproduce the width and current dependence of the measured CT-EL peak for a large number of donor-acceptor combinations. The fitted dominant phonon modes compare well with the values measured using the spectral line narrowing technique. Importantly, the calculations show that CT-EL originates from a narrow, non-thermalized subset of all available CT states, which can be understood by considering the kinetic microscopic process with which electron-hole pairs meet and recombine. Despite electron-hole pairs being strongly bound in organic materials, the charge separation process following photo-excitation is found to be extremely efficient and independent of the excitation energy. However, at low photon energies where the charges are excited deep in the tail of the DOS, it is intuitively expected for the extraction yield to be quenched. Internal Quantum Efficiency (IQE) experiments for different material systems show both inefficient and efficient charge dissociation for excitation close to the CT energy. This finding is explained by kinetic Monte Carlo simulations accounting for a varying degree of e-h delocalization, where strongly bound localized CT pairs (< 2nm distance) are doomed to recombine at low excitation energies while extended delocalization over 3-5nm yields an increased and energy-independent IQE. Using a single material parameter set, the experimental CT electroluminescence and absorption spectra are reproduced by the same kMC model by accounting for the vibronic progression of the calculated 0-0 transition. In contrast to CT-EL, CT-absorption probes the complete CT manifold. Charge transport in organic solar cells is currently modelled as either an equilibrium or a non-equilibrium process. The former is described by drift-diffusion (DD) equations, which can be calculated quickly but assume local thermal equilibrium of the charge carriers with the lattice. The latter is described by kMC models, that are time-consuming but treat the charge carriers individually and can probe all relevant time and energy scales. A hybrid model that makes use of the multiple trap and release (MTR) concept in combination with the DD equations is shown to describe both steady-state space charge limited conductivity experiments and non-equilibrium time-resolved transport experiments using a single parameter set. For the investigated simulations, the DD-MTR model is in good agreement with kMC and ~10 times faster. Steady-state mobilities from DD equations have been argued to be exclusively relevant for operating OPVs while charge carrier thermalization and non-equilibrium time-dependent mobilities (although acknowledged) can be disregarded. This conclusion, based on transient photocurrent experiments with ?s time resolution, is not complete. We show that non-equilibrium kMC simulations can describe the extraction of charge carriers from subps to 100 ?s timescales with a single parameter set. The majority of the fast charge carriers, mostly non-thermalized electrons, are extracted at time scales below the resolution of the experiment. In other words, the experiment resolves only the slower fraction of the charges, predominantly holes.

Download or read book Organic Light Emitting Diodes OLEDs and Optically Detected Magnetic Resonance ODMR Studies on Organic Materials written by and published by . This book was released on 2011 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic semiconductors have evolved rapidly over the last decades and currently are considered as the next-generation technology for many applications, such as organic light-emitting diodes (OLEDs) in flat-panel displays (FPDs) and solid state lighting (SSL), and organic solar cells (OSCs) in clean renewable energy. This dissertation focuses mainly on OLEDs. Although the commercialization of the OLED technology in FPDs is growing and appears to be just around the corner for SSL, there are still several key issues that need to be addressed: (1) the cost of OLEDs is very high, largely due to the costly current manufacturing process; (2) the efficiency of OLEDs needs to be improved. This is vital to the success of OLEDs in the FPD and SSL industries; (3) the lifetime of OLEDs, especially blue OLEDs, is the biggest technical challenge. All these issues raise the demand for new organic materials, new device structures, and continued lower-cost fabrication methods. In an attempt to address these issues, we used solution-processing methods to fabricate highly efficient small molecule OLEDs (SMOLEDs); this approach is costeffective in comparison to the more common thermal vacuum evaporation. We also successfully made efficient indium tin oxide (ITO)-free SMOLEDs to further improve the efficiency of the OLEDs. We employed the spin-dependent optically-detected magnetic resonance (ODMR) technique to study the luminescence quenching processes in OLEDs and organic materials in order to understand the intrinsic degradation mechanisms. We also fabricated polymer LEDs (PLEDs) based on a new electron-accepting blue-emitting polymer and studied the effect of molecular weight on the efficiency of PLEDs. All these studies helped us to better understand the underlying relationship between the organic semiconductor materials and the OLEDs' performance, and will subsequently assist in further enhancing the efficiency of OLEDs. With strongly improved device performance (in addition to other OLEDs' attributes such as mechanical flexibility and potential low cost), the OLED technology is promising to successfully compete with current technologies, such as LCDs and inorganic LEDs.

Download or read book Solution Processable Components for Organic Electronic Devices written by Beata Luszczynska and published by John Wiley & Sons. This book was released on 2019-09-16 with total page 686 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides first-hand insights into advanced fabrication techniques for solution processable organic electronics materials and devices The field of printable organic electronics has emerged as a technology which plays a major role in materials science research and development. Printable organic electronics soon compete with, and for specific applications can even outpace, conventional semiconductor devices in terms of performance, cost, and versatility. Printing techniques allow for large-scale fabrication of organic electronic components and functional devices for use as wearable electronics, health-care sensors, Internet of Things, monitoring of environment pollution and many others, yet-to-be-conceived applications. The first part of Solution-Processable Components for Organic Electronic Devices covers the synthesis of: soluble conjugated polymers; solution-processable nanoparticles of inorganic semiconductors; high-k nanoparticles by means of controlled radical polymerization; advanced blending techniques yielding novel materials with extraordinary properties. The book also discusses photogeneration of charge carriers in nanostructured bulk heterojunctions and charge carrier transport in multicomponent materials such as composites and nanocomposites as well as photovoltaic devices modelling. The second part of the book is devoted to organic electronic devices, such as field effect transistors, light emitting diodes, photovoltaics, photodiodes and electronic memory devices which can be produced by solution-based methods, including printing and roll-to-roll manufacturing. The book provides in-depth knowledge for experienced researchers and for those entering the field. It comprises 12 chapters focused on: ? novel organic electronics components synthesis and solution-based processing techniques ? advanced analysis of mechanisms governing charge carrier generation and transport in organic semiconductors and devices ? fabrication techniques and characterization methods of organic electronic devices Providing coverage of the state of the art of organic electronics, Solution-Processable Components for Organic Electronic Devices is an excellent book for materials scientists, applied physicists, engineering scientists, and those working in the electronics industry.

Download or read book Optoelectronic Organic Inorganic Semiconductor Heterojunctions written by Ye Zhou and published by CRC Press. This book was released on 2021-01-20 with total page 403 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optoelectronic Organic-Inorganic Semiconductor Heterojunctions summarizes advances in the development of organic-inorganic semiconductor heterojunctions, points out challenges and possible solutions for material/device design, and evaluates prospects for commercial applications. Introduces the concept and basic mechanism of semiconductor heterojunctions Describes a series of organic-inorganic semiconductor heterojunctions with desirable electrical and optical properties for optoelectronic devices Discusses typical devices such as solar cells, photo-detectors, and optoelectronic memories Outlines the materials and device challenges as well as possible strategies to promote the commercial translation of semiconductor heterojunctions-based optoelectronic devices Aimed at graduate students and researchers working in solid-state materials and electronics, this book offers a comprehensive yet accessible view of the state of the art and future directions.

Download or read book Wspc Reference On Organic Electronics The Organic Semiconductors In 2 Volumes written by Seth R Marder and published by World Scientific. This book was released on 2016-06-24 with total page 896 pages. Available in PDF, EPUB and Kindle. Book excerpt: This 2-volume set provides the reader with a basic understanding of the foundational concepts pertaining to the design, synthesis, and applications of conjugated organic materials used as organic semiconductors, in areas including organic photovoltaic devices, light-emitting diodes, field-effect transistors, spintronics, actuation, bioelectronics, thermoelectrics, and nonlinear optics.While there are many monographs in these various areas, the emphasis here is both on the fundamental chemistry and physics concepts underlying the field of organic semiconductors and on how these concepts drive a broad range of applications. This makes the volumes ideal introductory textbooks in the subject. They will thus offer great value to both junior and senior scientists working in areas ranging from organic chemistry to condensed matter physics and materials science and engineering.Number of Illustrations and Tables: 168 b/w illus., 242 colour illus., 13 tables.

Download or read book Organic Semiconductor Materials and Devices written by J. Weidner and published by The Electrochemical Society. This book was released on 2008-04 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: The papers included in this issue of ECS Transactions were originally presented in the symposium ¿Organic Semiconductor Materials and Devices¿, held during the 212th meeting of The Electrochemical Society, in Washington, DC, from October 7 to 12, 2007.

Download or read book High Performance Multi Component Organic Solar Cells written by Ismail Alperen Ayhan and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Renewable energies significantly gained in importance in the last decade. Due to worldwide ecological problems and global warming, much effort is needed to increase the awareness and protect earth from the impacts with respect to the climate changes. Particularly, the excessive use of fossil fuels force countries to figure out some alternative applications for the energy supply. Other than hydro and wind-based applications, solar energy becomes the most important renewable technology to reduce the carbon dioxide emission and worldwide photovoltaic systems have recently been installed by gradually rising. Since only China and India are building several coal powers every week for energy needs based-on their population1, it is very important to develop efficient and low-cost solar energy systems to attract attention for especially newly develop countries other than develop ones. Organic solar cells (OSCs) are one of the most promising solar energy systems due to some unique advantages, such as low-cost, lightweight, flexible, semitransparent, large area compatibility, easy fabrication (roll to roll), easy processing (from solution), and energy level tunability, which enables new fields of applications. In contrast to inorganic solar cells, high temperature fabrication techniques are not needed to prepare organic photovoltaics. In solution processed OSCs, the organic semiconductor materials are used in active layer to absorb light and convert it to electrical energy. The active layers containing donor and accepter components where the optimized morphology is achieved through an interpenetrating phase-separated donor-acceptor network that is called as bulk heterojunction. The efficiency of bulk heterojunction OSCs is strongly correlated with the morphology of their active layers, which requires an optimized distribution of the donor and acceptor domains. A large interface between donor and acceptor domains are needed to obtain efficient exciton dissociation at interface. Also, percolation pathways are required to transport the charges to the corresponding electrodes. The nanomorphology depends on tendency of the active layer components to crystallization and phase-separation. These morphological properties can be optimized by altering the process parameters, such as selection of materials and solvents, composition, thickness, and thermal treatments. Recently, OSCs has been remarkably enhanced with power conversion efficiency exceeding 16% by virtue of new materials development and device optimizations.2--4 It is commonly known that the limited absorption window of organic semiconductors causes low photon-harvesting ability from active layer. Multi-component organic solar cells, which consist of one donor and two acceptors, are a promising strategy for broadening the light absorption spectrum and enhancing the power conversion efficiency (PCE) of the organic photovoltaic devices, due to the diverse small molecular materials with different optical band gaps and good compatibility. In this dissertation, the binary and ternary blend systems were studied through optimizing processing parameters and the effect of these parameters on the structural, morphological, electrical and photovoltaic properties were investigated by performing UV-vis absorption, EQE measurement, Grazing-Incidence Wide-Angle X-ray Scattering (GIWAXS) and energy-filtered transmission electron microscopy (EFTEM). In the first part of dissertation, it is found that optimized blends share a universal fibril-like structure, where the polymer donor appears to dictate fibril size. In the second part of section, the effect of third component in ternary blend OSCs is discussed where the optimum morphology is achieved and if the ternary blend systems also have similar morphology such as fibril-like structure. As expected, the ternary blend system showed significant enhancement of device performance due to broadening of the absorption spectrum and the fill factor. We attribute that the high morphology compatibility of the ternary system can benefit to optimized electron/hole mobility and diminished recombination.

Download or read book Organic and Polymeric Materials and Devices written by Materials Research Society. Meeting and published by . This book was released on 2003 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of organic semiconductors has seen much development in the past years. Displays based on light-emitting diodes made of small organic molecules as well as polymers, have recently been commercialized. Other applications, such as electronic circuits for tagging, efficient photovoltaic devices and biosensors, have already been demonstrated. This volume brings together a "wish list" of leading researchers in the fields of chemistry, physics and technology of organic devices. Novel device concepts such as charge-generation layers, metal complexes and the use of heterojunctions are presented and should lead to further improvement in the efficiency of organic light-emitting diodes. In the field of organic transistors, major progress is reported on the charge-transport properties of organic semiconductors; mobilities up to 5cm2/Vs are reported for pentacene-based transistors. High mobility n-type materials, which enable the development of ambipolar organic electronic circuits, are also discussed. And new approaches to fully printable displays on substrates, such as textiles and paper, are presented. These may lead the way to new applications of organic optoelectronic devices.

Download or read book Progress in High Efficient Solution Process Organic Photovoltaic Devices written by Yang Yang and published by Springer. This book was released on 2015-02-17 with total page 421 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents an important technique to process organic photovoltaic devices. The basics, materials aspects and manufacturing of photovoltaic devices with solution processing are explained. Solution processable organic solar cells - polymer or solution processable small molecules - have the potential to significantly reduce the costs for solar electricity and energy payback time due to the low material costs for the cells, low cost and fast fabrication processes (ambient, roll-to-roll), high material utilization etc. In addition, organic photovoltaics (OPV) also provides attractive properties like flexibility, colorful displays and transparency which could open new market opportunities. The material and device innovations lead to improved efficiency by 8% for organic photovoltaic solar cells, compared to 4% in 2005. Both academic and industry research have significant interest in the development of this technology. This book gives an overview of the booming technology, focusing on the solution process for organic solar cells and provides a state-of-the-art report of the latest developments. World class experts cover fundamental, materials, devices and manufacturing technology of OPV technology.

Download or read book Proceedings of the 7th International Conference on Electrical Control and Computer Engineering Volume 2 written by Zainah Md. Zain and published by Springer Nature. This book was released on with total page 637 pages. Available in PDF, EPUB and Kindle. Book excerpt: