Download or read book Characterization and Synthesis of Organic Semiconductor Materials for Light emitting Diodes Structure property Relationship PHD written by Jeffrey David Anderson and published by . This book was released on 1999 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2004 with total page 854 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Characterization of Inorganic organic Hybrid Semiconductor Materials for Energy Applications written by Mojgan Roushan and published by . This book was released on 2012 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past few years, it has been shown that inorganic-organic hybrid semiconductors are promising candidates for optoelectronics and clean energy applications. These materials have the advantage of combining the excellent electrical, optical, thermal and transport properties of inorganic components with the flexibility, processability and structural diversity of the organic components. A representative of such materials is the inorganic-organic hybrids based on II-VI semiconductors. We have developed a unique class of II-VI based hybrids composed of alternating layers of double atomic slabs of Zn2S2 and organic amine molecules. The Zn2S2 based double-layer hybrids emit bright white light and their internal quantum efficiencies have reached ~33-35%, very close to the performance level of the (YAG):Ce3+ yellow phosphors presently dominating the white light emitting diodes (WLED) market. We have demonstrated that their band-gap and photoluminescence properties, quantum yield and color quality can be systematically tuned by varying the doping level and composition of inorganic and organic components. Therefore, these white-light emitting hybrid semiconductors represent a new type of single-phased phosphors made of semiconductor bulk materials with great promise for use in WLEDs which are of intense interest for general illuminations. Furthermore, we have successfully synthesized a series of new hybrid materials containing one-dimensional chains or two-dimensional layers of V-VI motifs with organic spacers between the channels or the layers. Inserting organic amines in these crystal lattices reduces the thermal conductivity without any significant effect on the electrical conductivity, and thus, it may give rise to an increase in the figure of merit, a parameter that characterizes the effectiveness of thermoelectric devices. The ability to tune the optical, electrical, and thermal properties, coupled with their high fluorescence quantum yield, solution processability, low-temperature and cost-effective one-pot synthesis, precisely controllable stoichiometry and high yield, not only make these hybrid materials promising candidates for use in WLEDs, but also highly versatile semiconductors for a range of applications such as optoelectronics, energy generation, and conversion devices.

Download or read book Porphyrin Materials for Organic Light Emitting Diodes written by Brian Tuffy and published by LAP Lambert Academic Publishing. This book was released on 2011-10-15 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic light-emitting diode technology is evolving rapidly with commercial applications in recent years. OLED materials and design are moving into an advanced stage with optimising techniques becoming more important. This work presents the use of porphyrin materials for organic electronics, specifically for organic light-emitting diodes using phosphorescent emission. The porphyrins show interesting photophysical properties which allow for an exploitation of the normally forbidden triplet energy states to achieve a significant enhancement in the device efficiency. This research presents a simple host–guest system where this concept is demonstrated. Various porphyrin structures are synthesised and tuned for OLED performance; from this, we can learn how chemical structure relates to the exciton dynamics and their resulting light emission. It is hoped that this work outlines a possible route to phosphorescent OLED technologies.

Download or read book Low Molecular Weight Organic Semiconductors written by Thorsten U. Kampen and published by John Wiley & Sons. This book was released on 2011-08-04 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: This up-to-date reference for students and researchers in the field is the first systematic treatment on the property measurements of organic semiconductor materials. Following an introduction, the book goes on to treat the structural analysis of thin films and spectroscopy of electronic states. Subsequent sections deal with optical spectroscopy and charge transport. An invaluable source for understanding, handling and applying this key type of material for physicists, materials scientists, graduate students, and analytical laboratories.

Download or read book Structure property Relationships for Organic Semiconductor Materials written by Ming Lee Tang and published by . This book was released on 2008 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Understanding the Morphology at Donor acceptor Interfaces in Organic Semiconductors written by Zixuan Guo and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic electronic devices, including organic photovoltaics (OPV), organic light-emitting diodes (OLEDs), and organic field-effect transistors (OFETs), have become increasingly important in consumer electronic applications due to the development of organic semiconductors, including organic small molecules, and conjugated polymers. They have advantages such as light weight, flexibility/stretchability, and the ability for roll-to-roll manufacturing. The structure and mechanism of organic devices are analogous to inorganic semiconductor devices, where donor materials (p-type) and acceptor materials (n-type) are used to create interfaces. To build high-performance organic electronic devices, it is essential to understand functionalities of organic heterojunction because they are building blocks of electronics. Organic heterojunction is interfaces created between donor and acceptor organic semiconductors. Exciting electronic action of devices occurs at organic interfaces. From a fundamental viewpoint, the role of interfaces must have optimal electronic and physical communication to yield highly efficient devices. From a technological viewpoint, one must understand, control, and have a rational design of the desired electronic and optical properties at organic interfaces for the development of different electronics and a host of potential new device concepts that have not yet been developed or realized. In this dissertation, we will use organic semiconductors for organic photovoltaics (OPV) as an example to investigat organic heterojunction interfaces, including interface fabrication, epitaxy, morphology control, and characterization, with the aim of building high-performance devices with good stability. We begin by discussing the growth of organic single-crystalline crystals with controlled orientations. Materials used are two small molecules: zinc phthalocyanine (ZnPc, p-type) and 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA, n-type). In this study, a self-built vertical physical vapor transport (v-PVT) chamber is used for crystallization, and a graphene-coated substrate is used to control molecular packing. Although ZnPc and PTCDA have a planar molecular shape and face-on packing motif on graphene, we find that they have different growth modes. Such growth mechanism difference can be explained by competition between intermolecular and molecule-graphene interactions. We then continue the abovementioned study by building model heterojunctions on graphene substrates using ZnPc and PTCDA. We discover that thermodynamics and kinetics of the system affect P-N junction morphology. We find that ZnPc and PTCDA form the "line-on-line" organic weak epitaxy at heterojunction interfaces from X-ray studies and crystallography refinement. We also verify that P-N junctions can generate electron-hole pairs. This work will advance the knowledge and create enabling opportunities to fabricate single-crystalline-oriented nanostructures. Besides using organic small molecules, we also explore the structure-property-performance relationship of conjugated block copolymers (BCPs) for OPV applications. In this work, a new donor-acceptor BCP is synthesized and added into polymer blend solar cells. We find that adding BCP could potentially retain the relative degree of crystallinity of [pi]-[pi] stacking regions, and decrease the detrimental interaction between donor polymer and electrode under thermal stress, thus improving the solar device's thermal stability by 30%. Finally, we explore the possibility of using graphene engineering for epitaxial growth dynamics control of organic small molecules. We determine that two distinct, alternating morphologies of ZnPc crystals are simultaneously observed on a single epitaxial SiC-graphene substrate. We hypothesize that the different morphologies arise from electronic structure and surface energy differences of underlying SiC-graphene regions ZnPc is grown on. The result will enable selective patterning of organic semiconductors for use in advanced warfare device applications. We hope these studies throughout this work will advance knowledge on fundamental crystallization mechanisms, interface engineering, morphology control, and characterization in organic crystalline systems. This work could further produce various future architectures for different applications in organic electronics.

Download or read book Organic Light Emitting Devices written by Klaus Müllen and published by John Wiley & Sons. This book was released on 2006-05-12 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt: This high-class book reflects a decade of intense research, culminating in excellent successes over the last few years. The contributions from both academia as well as the industry leaders combine the fundamentals and latest research results with application know-how and examples of functioning displays. As a result, all the four important aspects of OLEDs are covered: - syntheses of the organic materials - physical theory of electroluminescence and device efficiency - device conception and construction - characterization of both materials and devices. The whole is naturally rounded off with a look at what the future holds in store. The editor, Klaus Muellen, is director of the highly prestigious MPI for polymer research in Mainz, Germany, while the authors include Nobel Laureate Alan Heeger, one of the most notable founders of the field, Richard Friend, as well as Ching Tang, Eastman Kodak's number-one OLED researcher, known throughout the entire community for his key publications.

Download or read book Organic Light Emitting Transistors written by Michele Muccini and published by John Wiley & Sons. This book was released on 2016-04-25 with total page 287 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides an overview of the developments and applications of Organic Light Emitting Transistors (OLETs) science and technology This book discusses the scientific fundamentals and key technological features of Organic Light Emitting Transistors (OLETs) by putting them in the context of organic electronics and photonics. The characteristics of OLETs are benchmarked to those of OLEDs for applications in Flat Panel Displays and sensing technology. The authors provide a comparative analysis between OLED and OLET devices in order to highlight the fundamental differences in terms of device architecture and working principles, and to point out the enabling nature of OLETs for truly flexible displays. The book then explores the principles of OLET devices, their basic optoelectronic characteristics, the properties of currently available materials, processing and fabrication techniques, and the different approaches adopted to structure the active channel and to control organic and hybrid interfaces. Examines the photonic properties of OLETs, focusing on the external quantum efficiency, the brightness, the light outcoupling, and emission directionality Analyzes the charge transport and photophysical properties of OLET, emphasizing the excitonic properties and spatial emitting characteristics Reviews the key building blocks of the OLET devices and their role in determining the device’s performance Discusses the challenges in OLET design, namely color gamut, power efficiency, and reliability Presents key applications of OLET devices and their potential impact on display technology and sensing Organic Light-Emitting Transistors: Towards the Next Generation Display Technology serves as a reference for researchers, technology developers and end-users to have a broad view of the distinguishing features of the OLET technology and to profile the impact on the display and sensing markets.

Download or read book Synthesis and Characterization of Functional Oligomers and Polymers for Organic Light Emitting Diodes written by Sudhakar Madhusoodhanan and published by . This book was released on 2004 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Tailoring the Properties of Organic Semiconductors Through Heteroatoms written by Julia Schneider and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Incorporating heteroatoms is a powerful technique to tune the properties of organic semiconductors. Understanding the structure-property relationships associated with heteroatoms is imperative for the design of new materials for organic electronics. In this dissertation we study the effect of sulfur and nitrogen heteroatoms on the electronic, optical, and supramolecular assembly properties of organic semiconductors. This work focuses on the synthesis of new polymers and small molecules that contain heteroatoms in the pi-conjugated core and/or in substituents, as well as the full characterization of these materials. The structures presented include thienothiophene vinylene polymers with alkylsulfanyl and alkylsulfonyl substituents, a thienothiophene--thiazolothiazole trimer, diazabenzopyrene, and diazaperylene. Device studies in photovoltaics and field-effect transistors were performed to gain insight on structure-property relationships and the effect of heteroatoms." --

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 Molecular Design of Organic Semiconductors for Electronic Devices and Their Application in Flexible Light Emitting Diodes written by Hermona K. Pandya and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The focus of the studies investigated in this work has been two-fold. In the first part, a structure-property study of three novel two-dimensional conjugated phenylenevinylene (PV) based isomers containing oxadiazole moieties for optoelectronic applications has been carried out. The compounds have been designed to serve as a model to study charge delocalization and transport as well as molecular symmetry in organic semiconductor molecules. These molecules are tetra-substituted at the central phenyl ring with two PV based arms and two oxadiazole derivatized PV (OXAPPV) arms. In the three molecules, termed p -, o -, and m -OXA-X, the OXAPPV arms are positioned in a para -, ortho - or meta -position, respectively, in relation to each other. Comparing these molecules, the role of symmetry and charge delocalization in this class of compounds has been explored. Despite having different linear segments, they have nearly identical photophysical properties suggesting a similar charge delocalization mechanism. However, in a LED with the molecules as emissive layers between aluminum and ITO electrodes and with poly(3,4-ethylenedioxythiophene) with poly(styrenesulfonate) (PEDOT:PSS) and lithium fluoride to aid in hole and electron injection, respectively, o -OXA-X exhibited the highest external quantum, luminance and power efficiencies. We explain these differences based on the changes in the film morphology between the three molecules. Supporting data from cyclic voltammetry and morphological data from atomic force microscopy, NMR studies, thermal characterization and x-ray diffraction studies are also reported. In the second part, in an effort to construct stable and high efficiency devices with a single emissive layer and with a stable cathode, flexible LEDs have been fabricated and tested in simple device configurations. Devices on flexible substrates have been made using either the 2D conjugated molecules or a soluble poly(phenylenevinylene) (PPV) and oxadiazole substituted PPV derivatized random copolymer, RC30, as the emissive layer and higher work function aluminum cathodes and compared with control devices on glass substrates. In all devices PEDOT:TSS has been used as the hole transporting layer and a thin layer of cesium fluoride or lithium fluoride has been employed at the polymer/cathode interface to aid in electron injection. For the RC30 polymer, devices on plastic substrates with a lithium fluoride interlayer performed the best, exhibiting up to 1% external quantum efficiency and an average of 0.8% and luminance of 1600 cd/m 2 at 40 mA/cm2 (7.8 V). Stability of this device and morphology of the emissive film have also been investigated.

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.

Download or read book Synthetic Control of Organic Semiconductor Excited States written by Tabitha Ann Clem and published by . This book was released on 2010 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work describes the synthesis, and study of new organic and organometallic compounds designed to possess modified excited states for applications in electronic devices, with a particular focus on photovoltaics. The first chapter introduces the origin of semiconducting behavior in conjugated polymers, and how the properties of these semiconductors ultimately impact the fundamental physical processes occurring in organic electronic devices. The second chapter describes the synthesis, optoelectronic properties, and photovoltaic performance of a small molecule oligothiophene analog that possesses a considerable redshift in absorption relative to an unmodified oligothiophene. This redshift in absorption is the result of using a fused thiophene unit that acts as a driving force to enable dearomatization of the oligothiophene unit. The third chapter describes the preparation of wide band gap, phosphorescent cyclometalated platinum polymers and their application to bilayer photovoltaic devices where an increase in photocurrent is observed, and is attributed to an increase in the exciton diffusion length arising from formation of triplet excitons. The fourth chapter presents further development of cyclometalated platinum polymers, with a focus on tuning the photophysical properties and studying these materials in bulk heterojunction photovoltaic devices. The fifth chapter presents a study of cyclometalated platinum and iridium small molecules, describing their photophysical properties and solid-state structure, and exploring the application of these complexes to light emitting diodes. The final chapter describes the development of polythiophenes containing highly polarizable functional groups, with particular attention to the effect of these modifications on the optoelectronic properties and the dielectric constants of the resulting polymers. Together, these chapters present a study encompassing the modification of excited states in organic semiconductors, beginning with light absorption, continuing to modification of the spin state of the exciton, and ultimately modifying the dielectric constant of the active layer materials to affect charge separation and transport. Utilizing materials developed based on these principles provides an attractive new route to altering and enhancing the basic steps involved in the operation of organic electronic devices, ultimately producing both an improved understanding of the mechanism of device operation, and improved device performance.

Download or read book Directory of Graduate Research written by American Chemical Society. Committee on Professional Training and published by . This book was released on 2005 with total page 1932 pages. Available in PDF, EPUB and Kindle. Book excerpt: Faculties, publications and doctoral theses in departments or divisions of chemistry, chemical engineering, biochemistry and pharmaceutical and/or medicinal chemistry at universities in the United States and Canada.

Download or read book American Doctoral Dissertations written by and published by . This book was released on 1973 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt: