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Functionalization Of Organic Semiconductors And Other Carbon Based Materials By Self Assembled Monolayers Sams And Charge Transport In Organic Field Effect Transistors Ofets
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Book Synopsis Functionalization of Organic Semiconductors and Other Carbon-based Materials by Self-assembled Monolayers (SAMs) and Charge Transport in Organic Field-effect Transistors (OFETs) by : Bumsu Lee
Download or read book Functionalization of Organic Semiconductors and Other Carbon-based Materials by Self-assembled Monolayers (SAMs) and Charge Transport in Organic Field-effect Transistors (OFETs) written by Bumsu Lee and published by . This book was released on 2012 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Tuning Surface Properties Using Self-assembled Monolayers for Various Applications by : Yekaterina Leonidovna Lyubarskaya
Download or read book Tuning Surface Properties Using Self-assembled Monolayers for Various Applications written by Yekaterina Leonidovna Lyubarskaya and published by . This book was released on 2014 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The research presented in this dissertation focuses on the study of self-assembled monolayers (SAMs) in the modification of surface properties of different substrates for various applications. Self-assembled monolayers are organic molecules that can be deposited on a variety of surfaces, such as those of metals, metal-oxides, and semiconductors. Formation of SAMs on any inorganic material provides a ubiquitous way to impart desirable chemical and physical properties of organic and biological molecules to the inorganic substrate. It has been demonstrated that single molecules and their self-assembled monolayers can significantly alter the physical and electronic properties of inorganic conductors; moreover, studies have shown that the performance of many electrical devices can be transformed by modifying inorganic electrodes with organic SAMs. This is especially important for the development of next generation of ultra-compact electronic devices, in which the ability to control the interfacial charge-transport with a single monolayer of organic molecules would be ideal. We have developed different organic electronic architectures as test beds for studying the effect of monolayer properties, such as structural and geometrical parameters, on their electronic properties. By using a typical organic electronic device as a sensitive test platform, slight changes in a monolayer property, such as length, have been detected by studying the current- voltage characteristics (JV) of organic diodes functionalized with self-assembled monolayers (SAMs) of varying alkyl chain-length. Next, we describe the application of SAMs based on n-octylphosphonic acid (C8PA) and 1H,1H,2H,2H-perfluorooctanephosphonic acid (PFOPA) as anode buffer layers in C60-based organic photovoltaic (OPV) devices. We used the OPV platform to compare stabilities of organic monolayers exposed to ambient conditions with SAMs positioned inside working OPV devices. We found that the stabilities are different, suggesting the degradation mechanisms are distinct. The degradation of the OPV efficiency with respect to air exposure was significantly reduced with the perfluorinated PFOPA compared to the aliphatic C8PA. We attributed the OPV degradation to moisture diffusion from the top aluminum electrode and we discuss that the lowering of the anode work function is the result of hydrolysis of the SAM buffer layer. Next, we demonstrated the dependence of molecular electronic properties on the functional group substitution and that the changes in these properties can be measured using the organic light-emitting (OLED) platform. Specifically, we compared bilayered organic monomolecular systems immobilized on an inorganic electrode as the charge-injecting components of the organic light emitting diodes (OLEDs). Our bilayered interfaces comprise ordered inert primary and functional reactive layers, and they differ in only one parameter: the molecular structure of the terminal functional group. We demonstrate that we can visualize the differences in the charge transfer dynamics of two bilayered systems via patterned electroluminescence. In addition, we describe a new protocol for the preparation of shape-controlled multicomponent particles comprising metallic (Au and Ti), magnetic (Ni), and oxide (SiO2, TiO2) layers. First, we discuss the application and attractiveness of the colloidal structures, Janus Particles (JPs), that possess two different surfaces, varying either in polarity, hydrophilicity, etc. Next, we present our method for specifically controlling the composition, shape, and size of the micro-JPs. We demonstrate how this protocol permits fabrication of non-symmetrical particles by orthogonally functionalizing their opposite sides using well-established organosilanes and thiol chemistries (based on SAMs). We propose that these colloids may be used as convenient materials for studying non-symmetrical self-assembly at the meso- and micro-scales, due to their unique geometries and surface chemistries"--Pages viii-x.
Book Synopsis Organic Field-Effect Transistors by : Zhenan Bao
Download or read book Organic Field-Effect Transistors written by Zhenan Bao and published by CRC Press. This book was released on 2018-10-03 with total page 578 pages. Available in PDF, EPUB and Kindle. Book excerpt: The remarkable development of organic thin film transistors (OTFTs) has led to their emerging use in active matrix flat-panel displays, radio frequency identification cards, and sensors. Exploring one class of OTFTs, Organic Field-Effect Transistors provides a comprehensive, multidisciplinary survey of the present theory, charge transport studies, synthetic methodology, materials characterization, and current applications of organic field-effect transistors (OFETs). Covering various aspects of OFETs, the book begins with a theoretical description of charge transport in organic semiconductors at the molecular level. It then discusses the current understanding of charge transport in single-crystal devices, small molecules and oligomers, conjugated polymer devices, and charge injection issues in organic transistors. After describing the design rationales and synthetic methodologies used for organic semiconductors and dielectric materials, the book provides an overview of a variety of characterization techniques used to probe interfacial ordering, microstructure, molecular packing, and orientation crucial to device performance. It also describes the different processing techniques for molecules deposited by vacuum and solution, followed by current technological examples that employ OTFTs in their operation. Featuring respected contributors from around the world, this thorough, up-to-date volume presents both the theory behind OFETs and the latest applications of this promising technology.
Book Synopsis Semiconducting Polymers by : Georges Hadziioannou
Download or read book Semiconducting Polymers written by Georges Hadziioannou and published by John Wiley & Sons. This book was released on 2006-12-15 with total page 786 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of semiconducting polymers has attracted many researchers from a diversity of disciplines. Printed circuitry, flexible electronics and displays are already migrating from laboratory successes to commercial applications, but even now fundamental knowledge is deficient concerning some of the basic phenomena that so markedly influence a device's usefulness and competitiveness. This two-volume handbook describes the various approaches to doped and undoped semiconducting polymers taken with the aim to provide vital understanding of how to control the properties of these fascinating organic materials. Prominent researchers from the fields of synthetic chemistry, physical chemistry, engineering, computational chemistry, theoretical physics, and applied physics cover all aspects from compounds to devices. Since the first edition was published in 2000, significant findings and successes have been achieved in the field, and especially handheld electronic gadgets have become billion-dollar markets that promise a fertile application ground for flexible, lighter and disposable alternatives to classic silicon circuitry. The second edition brings readers up-to-date on cutting edge research in this field.
Book Synopsis Investigating the Nucleation, Growth, and Energy Levels of Organic Semiconductors for High Performance Plastic Electronics by : Ajay Virkar
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.
Book Synopsis Organic Optoelectronic Materials by : Yongfang Li
Download or read book Organic Optoelectronic Materials written by Yongfang Li and published by Springer. This book was released on 2015-05-30 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume reviews the latest trends in organic optoelectronic materials. Each comprehensive chapter allows graduate students and newcomers to the field to grasp the basics, whilst also ensuring that they have the most up-to-date overview of the latest research. Topics include: organic conductors and semiconductors; conducting polymers and conjugated polymer semiconductors, as well as their applications in organic field-effect-transistors; organic light-emitting diodes; and organic photovoltaics and transparent conducting electrodes. The molecular structures, synthesis methods, physicochemical and optoelectronic properties of the organic optoelectronic materials are also introduced and described in detail. The authors also elucidate the structures and working mechanisms of organic optoelectronic devices and outline fundamental scientific problems and future research directions. This volume is invaluable to all those interested in organic optoelectronic materials.
Book Synopsis Charge Transport in Organic Electronic Devices by : Zachary Alan Lamport
Download or read book Charge Transport in Organic Electronic Devices written by Zachary Alan Lamport and published by . This book was released on 2018 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: The electrical properties of devices based on an organic compound result from the structure of the molecules, their solid-state packing, efficiency of charge injection from the electrodes, and the fabrication procedures. The length scales of interest can also vary widely, ranging from a few nanometers in the case of charge transport through single molecules or two-dimensional molecular ensembles, to tens of micrometers in devices focusing on thin films or molecular crystals. The work outlined in this thesis examines the characteristics of electronic devices at both extremes by incorporating organic molecules in molecular rectifiers and organic field-effect transistors (OFETs). We successfully designed and fabricated molecular rectifiers based on self-assembled monolayers and identified relevant structure-function relationships. We elucidate the dependence of the rectification behavior on molecular length and structure, and found that the degree of rectification is enhanced in shorter molecules and linearly dependent on the strength of the molecular dipole moment. We further developed compounds that, when included into the molecular diodes, rectified current by as much as three orders of magnitude depending on their structure. This performance is on par with that of the best molecular rectifiers obtained on a metallic electrode, but it has the advantage of lower cost and more efficient integration with current silicon technologies, which may yield hybrid systems that can expand the use of silicon towards novel functionalities governed by the molecular species grafted onto its surface. We then explored charge transport in OFETs using the organic semiconductor 7,14-bis(trimethylsilylethynyl)benzo[k]tetraphene (TMS-BT). We produced thin-film OFETs which exhibited more efficient electronic transport than single crystal devices of the same material, in spite of the inherent presence of grain boundaries. We explained these findings in terms of charge transport anisotropy and electronic trap formation at the interface between the semiconductor and dielectric. We further reduced aggressively the contact resistance in small molecule and polymer OFETs by varying the metal deposition rate, which resulted in over 5 times improved charge carrier mobility compared with the best reported devices with identical composition and structure. The obtained contact resistance normalized over the channel width was 500 Ωcm, and the corresponding devices exhibited charge carrier mobilities of 19.2 cm2/Vs for 2,8-difluoro-5,11-bis(triethylsilylethynyl) anthradithiophene (diF-TES ADT) and 10 cm2/Vs for indacenodithiophene-co-benzothiadiazole copolymer (C16IDTBT), with minimal dependence on the gate voltage.
Book Synopsis Organic Flexible Electronics by : Piero Cosseddu
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
Book Synopsis Organic Solar Cells by : Wallace C.H. Choy
Download or read book Organic Solar Cells written by Wallace C.H. Choy and published by Springer Science & Business Media. This book was released on 2012-11-19 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic solar cells have emerged as new promising photovoltaic devices due to their potential applications in large area, printable and flexible solar panels. Organic Solar Cells: Materials and Device Physics offers an updated review on the topics covering the synthesis, properties and applications of new materials for various critical roles in devices from electrodes, interface and carrier transport materials, to the active layer composed of donors and acceptors. Addressing the important device physics issues of carrier and exciton dynamics and interface stability and novel light trapping structures, the potential for hybrid organic solar cells to provide high efficiency solar cells is examined and discussed in detail. Specific chapters covers key areas including: Latest research and designs for highly effective polymer donors/acceptors and interface materials Synthesis and application of highly transparent and conductive graphene Exciton and charge dynamics for in-depth understanding of the mechanism underlying organic solar cells. New potentials and emerging functionalities of plasmonic effects in OSCs Interface Degradation Mechanisms in organic photovoltaics improving the entire device lifetime Device architecture and operation mechanism of organic/ inorganic hybrid solar cells for next generation of high performance photovoltaics This reference can be practically and theoretically applied by senior undergraduates, postgraduates, engineers, scientists, researchers, and project managers with some fundamental knowledge in organic and inorganic semiconductor materials or devices.
Book Synopsis Surface Functionalization with Amino Based Self-assembled Monolayers by : Dominik Meyer
Download or read book Surface Functionalization with Amino Based Self-assembled Monolayers written by Dominik Meyer and published by . This book was released on 2015 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :Nikolaos Felekidis Publisher :Linköping University Electronic Press ISBN 13 :9176852717 Total Pages :60 pages Book Rating :4.1/5 (768 download)
Book Synopsis Effects of Energetic Disorder on the Optoelectronic Properties of Organic Solar Cells by : Nikolaos Felekidis
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.
Book Synopsis Control of On-surface Assembly of Organic Semiconducting Molecules by : Chaoying Fu
Download or read book Control of On-surface Assembly of Organic Semiconducting Molecules written by Chaoying Fu and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Molecular self-assembly, a promising bottom-up strategy for nanofabrication of functional devices, utilizes non-covalent interactions to yield well-defined supramolecular nanostructures. This method provides an inexpensive and versatile route to build the desired nanoarchitectures as compared to current top-down nanolithography methods. On the other hand, understanding and control of the supramolecular ordering of organic semiconducting (OSC) molecules at the interface is also crucial for optimization of thin-film optoelectronic applications. The supramolecular packing of OSC molecules in an active layer at the interface defines the exciton and charge transport properties and hence influences the device efficiency. This thesis studies the self-assembly properties of tailor-made OSC molecules. These molecules possess extended [pi]-conjugation and non-covalent intermolecular binding (e.g. hydrogen bonding) motifs and were designed to explore on-surface assembly of functional supramolecular architectures and two-dimensional (2D) polymers ("organic graphenes"). A series of derivatives of two isomeric tetrathienoanthracenes (TTAs), p-type semiconducting molecules, are designed and synthesized with different functionalities enabling their further chemical modification, their self-assembly via weak intermolecular interactions (i.e. hydrogen bonding, halogen bonding) and their polymerization. The versatile TTA derivatives are used to build 2D nanostructures and investigate the role of building block symmetry in controlling the order. The supramolecular packing of the OSC molecules at the interface is highly relevant for applications in organic field effect transistors (OFETs), where a charge transport mainly occurs within the first few layers close to the organic-dielectric interface. In this thesis, the initial stages of film growth of n-type semiconductors, mono-alkylated naphthalenediimides (NDI-R), are explored in solution and through vapor deposition on both conductive (HOPG) and insulating (SiO2) surfaces. The study indicates the retention of hydrogen bonding throughout the thin film growth, on both surfaces, mimicking the electrode and gate interfaces of actual OFET devices. Finally, the supramolecular ordering of diaryl diketopyrrolopyrrole (DPP), a common moiety for high-efficiency ambipolar OSC, is investigated as models of the corresponding oligomers and polymers. The effect of aryl-substituents on the hydrogen bonding of the structurally similar (hetero)aromatic-DPP building blocks is investigated in both molecular 2D self-assembly and crystal structures. Also, the mutual roles of alkyl chains and pending aryl substituents on dialkylated diaryl-DPP molecular planarity and packing are thoroughly assessed at both monolayer and bulk crystal levels.Overall, this thesis explores the relationship between the molecular structures and the on-surface supramolecular orderings of organic semiconducting molecules. It also establishes a general methodology for studying on-surface assemblies of such materials, integrating scanning tunneling microscopy (STM), atomic force microscopy (AFM), XRD and DFT analysis to create an overall view of molecular assembly growing from the surface, and evolving into thin films and, eventually, bulk crystals." --
Book Synopsis Field Effect Investigations of Charge Carrier Transport in Organic Semiconductors by : Elizabeth von Hauff
Download or read book Field Effect Investigations of Charge Carrier Transport in Organic Semiconductors written by Elizabeth von Hauff and published by . This book was released on 2005 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic semiconductors are potentially a cost and energy effective alternative to conventional technologies. The understanding of charge transport in these materials and minimizing electrical losses in organic devices is essential to improve device output. In this thesis the transport properties of charge carriers in solution processed organic semiconductors were investigated via field effect measurements. Measurements of the temperature and electric field dependent charge carrier mobilities in organic field effect transistors (OFETs) is a good method for studying the transport properties in organic semiconductors. engl.
Book Synopsis Cross-linked Polymers as Dielectrics for Organic Field-effect Transistors by : Zied Fahem
Download or read book Cross-linked Polymers as Dielectrics for Organic Field-effect Transistors written by Zied Fahem and published by Cuvillier. This book was released on 2013-11-21 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic electronics are getting more and more interest from industrial companies and research groups in the last years since they enable many new applications, which could not be realized by inorganic materials [1{7]. Flexible displays [1], large-area sensors [1], light-emitting large surfaces [8], printable radio-frequency identification tags (RFID) for packaging or logistic industry [2] and many other systems which require exible, large area and low-cost electronic devices are now developed for the near future or even already commercialized. Organic light-emitting-diode (OLED) displays, for example, are now implemented in portable devices and have higher performance than the traditional LCD displays [9]. OLED displays are self illuminating and do not need back lightening, therefore they have higher brightness, contrast and viewing angle in comparison to LCD displays [9]. Many electronic devices producers implemented OLED displays in their high-end smartphones and SLR cameras [10], and recently LG (a Korean company) introduced a 55-inch OLED television [11]. Large-area solar cells based on organic materials have also found their way to commercialization [12]. All of these innovations were only possible after the introduction of organic conductors and semiconductors. Organic (semi)-conductors have the advantage of their low-cost processing technologies (e.g. printing or spray-coating). However, they have lower electrical conductivity, free charge carriers mobility [13] and packaging density than their inorganic counterparts. Therefore they are normally used in lowcost and low-performance applications, except in the case of OLED where they have clear advantages compared with other technologies. In order to produce fully exible devices, elementary devices for electronic circuits (e.g. transistors and diodes) need to be made with exible materials. The performance of these devices needs to be enhanced and their fabrication processes should be optimized to ensure their c
Book Synopsis Nanomaterials Chemistry by : C. N. R. Rao
Download or read book Nanomaterials Chemistry written by C. N. R. Rao and published by John Wiley & Sons. This book was released on 2007-09-24 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: With this handbook, the distinguished team of editors has combined the expertise of leading nanomaterials scientists to provide the latest overview of this field. They cover the whole spectrum of nanomaterials, ranging from theory, synthesis, properties, characterization to application, including such new developments as quantum dots, nanoparticles, nanoporous materials, nanowires, nanotubes, and nanostructured polymers. The result is recommended reading for everybody working in nanoscience: Newcomers to the field can acquaint themselves with this exciting subject, while specialists will find answers to all their questions as well as helpful suggestions for further research.
Book Synopsis Advances in Condensed-Matter and Materials Physics by : Jagannathan Thirumalai
Download or read book Advances in Condensed-Matter and Materials Physics written by Jagannathan Thirumalai and published by BoD – Books on Demand. This book was released on 2020-05-06 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book, Condensed Matter and Material Physics, incorporates the work of multiple authors to enhance the theoretical as well as experimental knowledge of materials. The investigation of crystalline solids is a growing need in the electronics industry. Micro and nano transistors require an in-depth understanding of semiconductors of different groups. Amorphous materials, on the other hand, as non-equilibrium materials are widely applied in sensors and other medical and industrial applications. Superconducting magnets, composite materials, lasers, and many more applications are integral parts of our daily lives. Superfluids, liquid crystals, and polymers are undergoing active research throughout the world. Hence profound information on the nature and application of various materials is in demand. This book bestows on the reader a deep knowledge of physics behind the concepts, perspectives, characteristic properties, and prospects. The book was constructed using 10 contributions from experts in diversified fields of condensed matter and material physics and its technology from over 15 research institutes across the globe.
Book Synopsis Non-conventional Building Blocks for Organic Electronics by : Panikki Chandima Bulumulla
Download or read book Non-conventional Building Blocks for Organic Electronics written by Panikki Chandima Bulumulla and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic semiconductors are potential candidates for replacing high-cost silicon electronics for low-end applications where high mobilities are not required. Owing to unique advantages such as solution processability, flexibility, lightweight, low cost with countless structural modifications, organic semiconductors can be realized for many applications using high throughput roll-to-roll fabrication techniques. Hence, a remarkable amount of scientific efforts have been dedicated to improving electronic and physical properties of these materials. Throughout the past two decades, many improvements in the field have been achieved by designing novel building blocks. Since efficiencies and mobilities in organic solar cells and transistors have stagnated, it is highly desirable to seek and develop non-conventional building blocks for organic electronics. In this dissertation, the fundamentals and recent developments of non-conventional materials are covered in Chapter 1. Operation principles, charge transport of organic field effect transistors and organic photovoltaics are introduced. Compared to conventional thiophene-based -electron donor materials, promising non-conventional pyrrole based donor materials employed in organic electronics are discussed and summarized. Similarly, non-conventional electron acceptors could be used to fabricate organic solar cells. By using inorganic semiconducting quantum dots (QDs), organic-inorganic hybrid solar cells could be fabricated. Different systems with polymer: QD solar cells are also discussed and summarized in chapter 1. Chapter 2 describes the effect on organic field effect transistor (OFET) properties of two novel small molecules containing terminal N-dodecylthieno[3,2-b]pyrrole (TP) donors and N-dodecylfuro[3,2-b]pyrrole (FP) donors with a central thiophene flanked 5,6-difluorobenzo[c][1,2,5]thiadiazole (FBT) acceptor. The influence on frontier molecular orbital energy levels, UV-vis absorption, electrochemical properties, OFET parameters and morphological effects were investigated. In chapter 3, the effect of flanking group on banana shape small molecules is discussed by using terminal N-dodecylthieno[3,2-b]pyrrole (TP) donors, and thiophene or furan flanked benzo[c][1,2,5]thiadiazole (BT) central units. Upon changing similar flanking groups, the curvature of the small molecules was changed. Thiophene flanked small molecule showed high hole mobility of 0.08 cm2 /V s while furan flanked small molecule performs poorly due to both heteroatom effect and the degree of curvature. Chapter 4 describes the extension of thieno[3,2-b]pyrrole based small molecules to polymers. A Novel conjugated polymer is synthesized by copolymerizing N-methylthieno[3,2-b]pyrrole and 2,5-bis(2-octyldodecyl)-3,6-di(thiophen-2-yl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione (DPP) via Stille coupling polymerization. With an optimized molecular weight, the polymer exhibited high hole mobility of 0.12 cm2 /V s in OFET devices. The high hole mobility reflects the potential of the thieno[3,2-b]pyrrole building block. Inorganic QDs also can be employed as electron acceptors compared to conventional fullerene derivatives in bulk heterojunction (BHJ) solar cells. However, they do not outperform conventional fullerene counterparts. Therefore in chapter 5, a facile method is described to generate thiol functionalized block copolymers to improve the interaction between photoactive polymers and QDs. By incorporating only 17 mol% of the thiol containing block a two-fold increase in power conversion efficiency was observed. The improved interaction was supported by atomic force microscopy and photoluminescence quenching studies.
