Download or read book Solution Processable Organic Semiconducting Materials for Thin Film Transistors and Photovoltaic Applications written by Sang-wŏn Ko and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic transistors and solar cells offer the potential advantages of low-cost, large-scale fabrication by solution processing techniques, and compatibility with both flexible and lightweight plastic substrates. Continuous development of new organic materials has improved their performance, thus enabling the commercialization of these conducting polymers in recent years. However, understanding the relationship between polymer packing structures and mobilities is still lacking. Furthermore, to enable a polymer to serve as an effective donor material in bulk heterojunction (BHJ) solar cells, several important properties have to be considered, such as band gap, absorption coefficient, effective charge transport, and a relatively deep HOMO. Needless to say, careful balancing of these properties remains challenging. Thus, this thesis aims to gain a better understanding of materials design rules to address the above issues using two types of conjugated polymers. First, new donor-acceptor copolymers were designed and synthesized to gain insights into designing efficient donor materials in BHJ solar cells. Second, poly(3,4-disubstituted thiophene) derivatives were designed and synthesized to study relationships between structural design, packing, charge transport property, and solar cell performance. In the first part of my thesis, I have prepared vinylene linked co-polymers in order to achieve low bandgap polymers by extending [Pi]-conjugation lengths. I found that the hole mobilities of the polymers scaled with the molecular weights in these amorphous polymers. Optical absorption at longer wavelengths was improved by eliminating torsions along the polymer backbones. Current density (Jsc) in BHJ solar cells depended on the overall intensity of absorption and hole mobility of donor materials. Comparing to the amorphous vinylene linked co-polymers, charge carrier mobility could be enhanced by employing thienopyrazine based co-polymers, which contain rigid fused aromatic rings promoting well ordered inter-chain packing. Removing of the adjacent thiophene groups around the thienopyrazine acceptor core markedly increased the optical absorption of the polymer and raised its ionization potential, resulting in power conversion efficiency (PCE) of 1.57%. This investigation on the new co-polymers could provide a useful guideline for designing efficient donors for BHJ solar cells. In the second part of my thesis, I designed and synthesized polythiophene derivatives to understand structure-property relationships in detail. Despite their slightly larger band gaps, polythiophene derivatives are nonetheless important active materials due to their high absorption coefficients and high charge transport mobilities. Furthermore, their facile synthesis and ease of structural modifications with various substituents are the advantages of using polythiophene derivatives as model conjugated polymer systems. To examine the influence of backbone twisting on performance of transistors and BHJ solar cells, I systematically imposed twists within the conjugated backbones of poly(3,4-disubtituted thiophene (P34AT) using a unsubstituted thiophene spacer of varying sizes. When a moderate twist was introduced to the P34AT backbone, a 19% enhancement in the open-circuit voltage vs. poly(3-hexylthiopene) based devices and high PCE (4.2%) were achieved without sacrificing the short-circuit current density and the fill factor. Despite the high charge transport mobility (0.17 cm2/Vs), P34AT hardly showed [Pi]-[Pi] stacking in X-ray diffraction, suggesting that a strong [Pi]-[Pi] stacking is not always necessary for high charge carrier mobility; in which other potential polymer packing motifs (in addition to the edge-on structure) can lead to a high device performance. To gain further knowledge in structure-property relationships of the less explored 3,4-disubstituted polythiophene system, various P34AT derivatives were prepared and their opto-electronic property, packing structure, and device performance were studied. Among P34AT derivatives containing fused thiophene rings, a higher PCE was achieved with a benzodithiophene based polymer (PDHBDT) having a larger absorption coefficient, higher hole mobility, and deeper HOMO. The PDHBDT also exhibited a thermotropic phase transition behavior, leading to mobility up to 0.46 cm2/Vs where the polymer backbones adapt an edge-on lamellar packing structure. In the last part of this thesis, low band gap P34AT derivatives, which incorporate electron withdrawing groups, were prepared to improve photocurrent. However, I observed that a low absorption coefficient and a low hole mobility limited current density in solar cells. Thus, this indicates that low band gap polymers with strong absorption properties and good charge transports are critical towards molecular design for achieving high PCE. Collectively, through rational design and characterization of these novel polymers, this thesis has illustrated that better understanding of molecular design rules for engineering opto-electronic properties and packing behavior, will lead to higher device performance.

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 Solution processable Organic Semiconducting Materials for Photovoltaic Applications written by Jianguo Mei and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Using diketopyrrolopyrrole (DPP) as an electron acceptor, amphiphilic discrete oligomers that can self-assemble into highly ordered nanostructures for organic field-effect transistors (OFETs) and molecular bulk-heterojunction solar cells (OPVs) were studied. Charge mobility as high as 4 x 10-3 cm2V-1s-1 was obtained from OFET measurement and PCEs of 0.7% were reported with a high fill factor of 0.58 in molecular BHJ solar cells with PCBM as an electron acceptor. A DPP-based thermocleavable polymer was also prepared and OPVs based on this polymer demonstrated an enhanced PCE of 1.44% upon cleavage. In chapter 6, isoindigo was introduced as an electron acceptor in [pi]-conjugated materials. Isoindigo-based oligothiophenes were prepared and used as donor materials in molecular bulkheterojunction OPVs and power conversion efficiencies up to 1.85% were achieved. Three isoindigo-based polymers were synthesized to validate the hypodissertation that charge mobility in conjugated polymers can be enhanced via enforcement of [pi]-[pi] interactions by means of introducing biphasic solubilizing groups. The results from SCLC modeling of J-V characteristics of single-carrier diodes are consistent with the hypodissertation presented where a nearly 10-fold increase in hole mobilities was observed for polymers with biphasic solubilizing group. In addition, a facile approach to isoindigo-based n-type conjugated polymers was also reported, in which the LUMO level as deep as -4.1 eV and deep HOMOs of ~6.0 eV were found. These polymers can be considered as an alternative to commonly used acceptors such as PCBM derivatives currently employed in polymer-based solar cell devices.

Download or read book Chemical Solution Synthesis for Materials Design and Thin Film Device Applications written by Soumen Das and published by Elsevier. This book was released on 2021-01-29 with total page 746 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chemical Solution Synthesis for Materials Design and Thin Film Device Applications presents current research on wet chemical techniques for thin-film based devices. Sections cover the quality of thin films, types of common films used in devices, various thermodynamic properties, thin film patterning, device configuration and applications. As a whole, these topics create a roadmap for developing new materials and incorporating the results in device fabrication. This book is suitable for graduate, undergraduate, doctoral students, and researchers looking for quick guidance on material synthesis and device fabrication through wet chemical routes. Provides the different wet chemical routes for materials synthesis, along with the most relevant thin film structured materials for device applications Discusses patterning and solution processing of inorganic thin films, along with solvent-based processing techniques Includes an overview of key processes and methods in thin film synthesis, processing and device fabrication, such as nucleation, lithography and solution processing

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 2019-06-11 with total page 688 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 Organic Semiconductors for Optoelectronics written by Hiroyoshi Naito and published by John Wiley & Sons. This book was released on 2021-08-02 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 Solution Processing of Inorganic Materials written by David Mitzi and published by John Wiley & Sons. This book was released on 2008-12-22 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt: Discover the materials set to revolutionize the electronics industry The search for electronic materials that can be cheaply solution-processed into films, while simultaneously providing quality device characteristics, represents a major challenge for materials scientists. Continuous semiconducting thin films with large carrier mobilities are particularly desirable for high-speed microelectronic applications, potentially providing new opportunities for the development of low-cost, large-area, flexible computing devices, displays, sensors, and solar cells. To date, the majority of solution-processing research has focused on molecular and polymeric organic films. In contrast, this book reviews recent achievements in the search for solution-processed inorganic semiconductors and other critical electronic components. These components offer the potential for better performance and more robust thermal and mechanical stability than comparable organic-based systems. Solution Processing of Inorganic Materials covers everything from the more traditional fields of sol-gel processing and chemical bath deposition to the cutting-edge use of nanomaterials in thin-film deposition. In particular, the book focuses on materials and techniques that are compatible with high-throughput, low-cost, and low-temperature deposition processes such as spin coating, dip coating, printing, and stamping. Throughout the text, illustrations and examples of applications are provided to help the reader fully appreciate the concepts and opportunities involved in this exciting field. In addition to presenting the state-of-the-art research, the book offers extensive background material. As a result, any researcher involved or interested in electronic device fabrication can turn to this book to become fully versed in the solution-processed inorganic materials that are set to revolutionize the electronics industry.

Download or read book Development of New Building Blocks for Constructing Novel Polymer Semiconductors for Organic Thin Film Transistors written by Zhuangqing Yan and published by . This book was released on 2013 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic semiconductors are envisioned to have widespread applications in flexible displays, radio-frequency identification (RFID) tags, bio- and chem-sensors, as well as organic solar cells. Polymer semiconductors are particularly suitable for the low-cost manufacture of organic electronics using printing techniques due to their excellent solution processability and mechanical properties. This work focuses on the development of two novel building blocks, IBDF and DTA, which can be used for the construction of high performance organic thin film transistors (OTFTs) and organic photovoltaics (OPVs). Two copolymers, P6-IBDF-T and P5-IBDF-T, and a homopolymer P6-IBDF were prepared using the IBDF building block. Copolymer P6-IBDF-T has been prepared via the Stille-coupling polymerization. This polymer exhibits a small band gap of 1.36 eV with HOMO/LUMO energy level of -5.69 eV/-4.43 eV. P6-IBDF-T showed stable electron transport performance in encapsulated thin film transistors and ambipolar transport performance in non-encapsulated TFTs. Balanced hole/electron mobilities of up to 8.2 ×10-3/1.0 ×10-2 cm2V-1s-1 was achieved in bottom-contact, bottom-gate organic thin film transistors. In addition, the broad absorption of the polymer over the UV-Vis range suggested that this polymer is suitable for applications in solar cells. The effect of conjugation on mobility and UV-vis spectra of the polymer was studied by comparing P5-IBDF-T with P6-IBDF-T. The ideal of indirect electron transition was proposed to explain the difference between UV-Vis light absorption spectra for these two polymers. DTA building block was used to construct four D-A copolymers, namely PDTA-T, PDTA-BT, PDAT-BTV, and PDTA-TT. These polymers were characterized by UV-Vis, CV, DSC, TGA, AFM and XRD. Device performance was also investigated on OTFTs. The device performance of DTA based polymer increased as the area of electron donor increase from T in PDTA-T to BTV in PDTA-BTV. PDTA-BTV exhibits hole mobility of 1.3×10-3 cm2 V-1 s-1 with Ion/Ioff value of ~103-4 in bottom-contact, bottom-gate organic thin film transistors. All DTA based copolymers exhibited small optical bandgaps (1.18 - 1.27 eV) and required none or moderate thermal treatment during fabrication process. These make them promising candidates for cost-effective OPV applications.

Download or read book Large Area and Flexible Electronics written by Mario Caironi and published by John Wiley & Sons. This book was released on 2015-01-13 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt: From materials to applications, this ready reference covers the entire value chain from fundamentals via processing right up to devices, presenting different approaches to large-area electronics, thus enabling readers to compare materials, properties and performance. Divided into two parts, the first focuses on the materials used for the electronic functionality, covering organic and inorganic semiconductors, including vacuum and solution-processed metal-oxide semiconductors, nanomembranes and nanocrystals, as well as conductors and insulators. The second part reviews the devices and applications of large-area electronics, including flexible and ultra-high-resolution displays, light-emitting transistors, organic and inorganic photovoltaics, large-area imagers and sensors, non-volatile memories and radio-frequency identification tags. With its academic and industrial viewpoints, this volume provides in-depth knowledge for experienced researchers while also serving as a first-stop resource for those entering the field.

Download or read book Organic Electronics II written by Hagen Klauk and published by John Wiley & Sons. This book was released on 2012-03-26 with total page 443 pages. Available in PDF, EPUB and Kindle. Book excerpt: Like its predecessor this book is devoted to the materials, manufacturing and applications aspects of organic thin-film transistors. Once again authored by the most renowned experts from this fascinating and fast-moving area of research, it offers a joint perspective both broad and in-depth on the latest developments in the areas of materials chemistry, transport physics, materials characterization, manufacturing technology, and circuit integration of organic transistors. With its many figures and detailed index, this book once again also serves as a ready reference.

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 Chemical Solution Synthesis for Materials Design and Thin Film Device Applications written by Soumen Das and published by Elsevier. This book was released on 2021-01-09 with total page 748 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chemical Solution Synthesis for Materials Design and Thin Film Device Applications presents current research on wet chemical techniques for thin-film based devices. Sections cover the quality of thin films, types of common films used in devices, various thermodynamic properties, thin film patterning, device configuration and applications. As a whole, these topics create a roadmap for developing new materials and incorporating the results in device fabrication. This book is suitable for graduate, undergraduate, doctoral students, and researchers looking for quick guidance on material synthesis and device fabrication through wet chemical routes. - Provides the different wet chemical routes for materials synthesis, along with the most relevant thin film structured materials for device applications - Discusses patterning and solution processing of inorganic thin films, along with solvent-based processing techniques - Includes an overview of key processes and methods in thin film synthesis, processing and device fabrication, such as nucleation, lithography and solution processing

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 Transparent Oxide Electronics written by Pedro Barquinha and published by John Wiley & Sons. This book was released on 2012-03-15 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transparent electronics is emerging as one of the most promising technologies for the next generation of electronic products, away from the traditional silicon technology. It is essential for touch display panels, solar cells, LEDs and antistatic coatings. The book describes the concept of transparent electronics, passive and active oxide semiconductors, multicomponent dielectrics and their importance for a new era of novel electronic materials and products. This is followed by a short history of transistors, and how oxides have revolutionized this field. It concludes with a glance at low-cost, disposable and lightweight devices for the next generation of ergonomic and functional discrete devices. Chapters cover: Properties and applications of n-type oxide semiconductors P-type conductors and semiconductors, including copper oxide and tin monoxide Low-temperature processed dielectrics n and p-type thin film transistors (TFTs) – structure, physics and brief history Paper electronics – Paper transistors, paper memories and paper batteries Applications of oxide TFTs – transparent circuits, active matrices for displays and biosensors Written by a team of renowned world experts, Transparent Oxide Electronics: From Materials to Devices gives an overview of the world of transparent electronics, and showcases groundbreaking work on paper transistors

Download or read book Advanced Materials for Printed Flexible Electronics written by Colin Tong and published by Springer Nature. This book was released on 2021-10-04 with total page 641 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive introduction to printed flexible electronics and their applications, including the basics of modern printing technologies, printable inks, performance characterization, device design, modeling, and fabrication processes. A wide range of materials used for printed flexible electronics are also covered in depth. Bridging the gap between the creation of structure and function, printed flexible electronics have been explored for manufacturing of flexible, stretchable, wearable, and conformal electronics device with conventional, 3D, and hybrid printing technologies. Advanced materials such as polymers, ceramics, nanoparticles, 2D materials, and nanocomposites have enabled a wide variety of applications, such as transparent conductive films, thin film transistors, printable solar cells, flexible energy harvesting and storage devices, electroluminescent devices, and wearable sensors. This book provides students, researchers and engineers with the information to understand the current status and future trends in printed flexible electronics, and acquire skills for selecting and using materials and additive manufacturing processes in the design of printed flexible electronics.

Download or read book Using Single Ion Conductors as Dielectrics in Organic Transistors written by Sarah Sheffield and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic electronics have the potential to revolutionize the electronics industry. Organic semiconductors and dielectric materials offer lower device-fabrication costs than silicon-based semiconductors since they can be solution processable and are critical for the advancement of flexible electronics. Thus far, these organic materials have been used in organic light emitting diode (OLED) displays, organic photovoltaic (OPV) solar cells, organic transistors, and biosensors. However, there are still challenges with organic semiconductors, as their performance is often lower than silicon-based semiconductors. Recent research on the morphology, orientation, and alignment of polymer semiconductors has shown that optimizing these parameters can improve performance. Additionally, refining the transistor gating mechanism has shown to be promising for improving the charge carrier mobility in the device, as well as for incorporating organic transistors into a wide range of applications. The most common organic transistors include organic field-effect transistors (OFETs), organic electrochemical transistors (OECTs) and electrolyte-gated transistors (EGTs). This dissertation focuses on the characterization of organic semiconducting polymers and single-ion conducting ionomer dielectrics in organic transistors for the improvement of bioelectronic devices. To rival traditional inorganic electronics, improving the charge carrier mobility of polymeric and small-molecule organic semiconductors is crucial. This relies on understanding the alignment, structural ordering, and molecular orientation in polymeric semiconducting thin films through structural and transport characterization techniques. This work investigates two semi-crystalline, polymeric semiconductors commonly used in OFETs: poly(3-hexylthiophene-2,5-diyl) (P3HT) and poly[2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene] (PBTTT-C14). P3HT and PBTTT-C14 thin films were cast on silicon wafers with a native oxide layer and characterized using surface overlayer attenuated total reflection (SO-ATR) Fourier transform infrared (FTIR) spectroscopy. The SO-ATR geometry of thin films has demonstrated an increase in the p-polarization character of the infrared evanescent wave as the film thickness was decreased between the internal reflection element and the substrate overlayer, achieving higher signal for thin films. The molecular orientation of the thiophene ring of the polymers, relative to surface normal of the substrate, was determined from the SO-ATR sampling geometry. This led to a better understanding of the alignment of semiconducting polymer thin films from this technique. Using this technique, the alignment of P3HT on a silicon substrate was found to vary with changing film thickness while the alignment of PBTTT-C14 on silicon substrates remained constant. In addition to traditional OFETs, electrolyte-gated transistors (EGTs) are promising in bioelectronics and biosensor applications due to their ability to amplify low electrical signals. EGTs use an electrolyte or ionic material in the dielectric layer which ionically drives the conduction channel at the semiconductor-dielectric interface in the presence of an applied voltage bias through the formation of an electrical double layer (EDL). Solid-state ionic materials and polymers, such as ionomers, are currently of interest as they are more processible than liquid ionic materials for large scale fabrication. This work uses Nafion, a single-ion conducting ionomer, as an electrolytic dielectric material for the improvement of charge carrier mobility in EGTs. Rubrene single crystals, a p-type crystalline small molecule semiconductor, were chosen as the semiconducting material since the crystallinity limits the device mechanism to only electrostatic doping. The rubrene single-crystal EGTs with a Nafion dielectric layer demonstrated higher charge carrier mobilities when compared to rubrene single-crystal OFETs with silicon dioxide dielectrics. The improvement of the charge carrier mobility can be attributed to the ionicity of the sulfonate end groups in the Nafion dielectric layer. While p-type organic semiconductors in OFETs and EGTs have been well-studied, n-type organic semiconductors have been subjected to numerous challenges. N-type organic semiconductors are more sensitive to air and water, leading to lower carrier mobilities and poor device performance. N,N'-bis(n-alkyl)-(1,7 and 1,6)-dicyanoperylene-3,4:9,10-bis(dicarboximide) (PDIF-CN2) is a promising n-type semiconductor and has been used in thin film and single-crystal organic transistors. PDIF-CN2 single crystals were fabricated by physical vapor transport (PVT) and used as the semiconductor in Nafion-gated EGTs. The PDIF-CN2 EGTs exhibited near zero threshold voltages and high on/off ratios. The Nafion-gated EGTs with n-type single-crystal semiconductors demonstrated higher electron carrier mobilities compared to n-type single-crystal OFETs with only silicon dioxide as the dielectric. However, the electron carrier mobilities in Nafion-gated EGTs were less than or comparable to the mobilities reported for other PDIF-CN2 single-crystal transistors.

Download or read book Semiconductors written by Martin I. Pech-Canul and published by Springer. This book was released on 2019-01-17 with total page 596 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a practical guide to optical, optoelectronic, and semiconductor materials and provides an overview of the topic from its fundamentals to cutting-edge processing routes to groundbreaking technologies for the most recent applications. The book details the characterization and properties of these materials. Chemical methods of synthesis are emphasized by the authors throughout the publication. Describes new materials and updates to older materials that exhibit optical, optoelectronic and semiconductor behaviors; Covers the structural and mechanical aspects of the optical, optoelectronic and semiconductor materials for meeting mechanical property and safety requirements; Includes discussion of the environmental and sustainability issues regarding optical, optoelectronic, and semiconductor materials, from processing to recycling.