Download or read book Exciton Coherence in 1D Phthalocyanine Based Organic Crystalline Thin Films written by KimNgan Burrill and published by . This book was released on 2020 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum coherence plays a vital role in the excitonic properties of organic semiconductors. Several theoretical and experimental studies have shown an unprecedented role of coherence in charge transfer and transport processes, which in turn can improve the performance of electronic devices. Specifically, an enhancement of exciton coherence size can result in fast energy transport and efficient charge separation. The ability to tailor the design and performance of organic electronics based on exciton coherence effects represents the possibility of ultrafast electronic applications in communication and information technology. The objective of this thesis is the excitonic coherence studies of 1D crystalline thin films of phthalocyanine-based organic semiconductors using steady-state and time-resolved photoluminescence spectroscopy (TRPL). One of the main focuses of this work is on investigating the correlation of intermolecular interactions, $\pi$ orbital overlap and dynamic disorders on the excitonic coherent behaviors in crystalline thin films of various phthalocyanine derivatives (i.e. H$_2$TPP, H$_2$OBPc, H$_2$OCPc, and H$_2$OBNc). Specifically, coherence lengths, exciton-phonon coupling strengths and the nearest neighbor (NN) interaction strengths are determined via: (1) the PL ratio of the excitonic coherence transition and its first vibrational replica and (2) the temperature evolution of radiative recombination lifetimes of coherent excitons. This study showed that the optimum coherence size and the robustness of excitonic coherence can be achieved by a complex interplay between NN interaction, vibrational energies and the coupling to vibrational modes. In particular, it is shown that the shortest NN distance does not ensure the achievement of maximum coherence length within the four investigated phthalocyanine species. Instead, the largest coherence length is measured in the octabutoxy derivative, where the saddle shape of the molecule and crystalline packing results in weaker coupling to the acoustic phonons modes despite having larger intermolecular NN distance. In addition, the effect of static and dynamic disorders on the behavior of exciton coherence is explored by alloying two phthalocyanine derivatives that are close in band gap energies and possess large coherence lengths, H$_2$OBPc and H$_2$OBNc. This study demonstrated the successful tuning of exciton coherence lengths and excitonic parameters in organic analogues of semiconductor alloys, H$_2$OBNc$_x$H$_2$OBPc$_{1-x}$. Furthermore, the correlation of exciton-phonon coupling and radiative recombination rate of coherent excitons with increasing alloy concentration or static disorders are successfully revealed.
Download or read book Strain Enhanced Coherent Exciton Polaron States in 1d Phthalocyanine Crystalline Thin Films written by Libin Liang and published by . This book was released on 2022 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic semiconductors are at the forefront of materials research, due to their desired electric and mechanical properties. They offer the unique opportunity to modify material properties during synthesis process, opening an avenue to the development of novel flexible and wearable electronic and photonic devices. Molecular excitons are of importance in organic semiconductor properties. While majority of research studies are centered on achieving good control of amorphous or polycrystalline thin film properties, the static disorder effect leads to poor device performance when compared to inorganic semiconductors with superior crystalline ordering. On the other hand, the macroscopic molecular long-range ordering can enhance device anisotropic properties, robust excitonic states and trigger coherent energy transfer region. Therefore, it requires further effort to fabricate thin films with macroscopic ordering, characterize the anisotropic properties of thin films and understand the effects of long-range intermolecular interactions on device performance. Materials in flexible devices will experience complex strain environment. There is a critical need for researchers to understand the effects of strain on thin films used in flexible electronics applications. It has been reported that lattice strain can enhance small-molecule organic semiconductor device performance by tuning the electron-phonon coupling. However, to fabricate novel flexible devices, it demands more research to explore the correlation between strain and bandgap transition, molecular vibration mode, exciton-phonon coupling, etc. For example, while the majority of strain studies focus on electric properties, strain-dependent optical and excitonic properties are less reported. Phthalocyanines (Pc's) are one of the small-molecules that can be applied in the organic flexible electronics as alternative for certain traditional silicon-based semiconductor applications such as field-effect transistors and photovoltaic devices. They have great potential for the development of novel electronic and photonic devices due to their high mobilities and strong intermolecular interactions from the [pi]-orbital overlap. Octabutoxy phthalocyanine (H2-OBPc) is a soluble derivative of the Pc which offers the solution-based thin film fabrication process. It provides a great platform to study the molecular exciton properties in 1D system. In this dissertation, H2-OBPc crystalline thin films with macroscopic grain size in millimeter scale are obtained with the pen-writing deposition technique. Orientations of transition dipole moment are resolved with the incident light orientation-dependent absorption measurement. Localized and coherent exciton-polarons are identified from temperature study of photoluminescence. Optical properties of H2-OBPc thin films at various strain are explored at room temperature. Strain-enhanced formation of delocalized exciton-polaron states is observed, and an 80% enhancement in photoluminescence intensity can be achieved with strain of 4.9%. Temperature studies were conducted to reveal the effect of strain on the excitonic properties. Results suggest strain can increase the relative strength between the intermolecular interaction and the activation energy, leading to the formation of coherent exciton-polaron states. This coherence can persist even with the presence of thermal fluctuations. These results grant H2-OBPc small molecules a promising application in the development of novel electronic devices.
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 Covalent Organic Frameworks written by Atsushi Nagai and published by CRC Press. This book was released on 2019-12-19 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rational synthesis of extended arrays of organic matter in bulk, solution, crystals, and thin films has always been a paramount goal of chemistry. The classical synthetic tools to obtain long-range regularity are, however, limited to noncovalent interactions, which usually yield structurally more random products. Hence, a combination of porosity and regularity in organic covalently bonded materials requires not only the design of molecular building blocks that allow for growth into a nonperturbed, regular geometry but also a condensation mechanism that progresses under reversible, thermodynamic, self-optimizing conditions. Covalent organic frameworks (COFs), a variety of 2D crystalline porous materials composed of light elements, resemble an sp2-carbon-based graphene sheet but have a different molecular skeleton formed by orderly linkage of building blocks to constitute a flat organic sheet. COFs have attracted considerable attention in the past decade because of their versatile applications in gas storage and separation, catalysis, sensing, drug delivery, and optoelectronic materials development. Compared to other porous materials, COFs allow for atomically precise control of their architectures by changing the structure of their building blocks, whereby the shapes and sizes of their pores can be well-tuned. Covalent Organic Frameworks is a compilation of different topics in COF research, from COF design and synthesis, crystallization, and structural linkages to the theory of gas sorption and various applications of COFs, such as heterogeneous catalysts, energy storage (e.g., semiconductors and batteries), and biomedicine. This handbook will appeal to anyone interested in nanotechnology and new materials of gas adsorption and storage, heterogeneous catalysts, electronic devices, and biomedical devices.
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 Quantum Dot Devices written by Zhiming M. Wang and published by Springer Science & Business Media. This book was released on 2012-05-24 with total page 375 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum dots as nanomaterials have been extensively investigated in the past several decades from growth to characterization to applications. As the basis of future developments in the field, this book collects a series of state-of-the-art chapters on the current status of quantum dot devices and how these devices take advantage of quantum features. Written by 56 leading experts from 14 countries, the chapters cover numerous quantum dot applications, including lasers, LEDs, detectors, amplifiers, switches, transistors, and solar cells. Quantum Dot Devices is appropriate for researchers of all levels of experience with an interest in epitaxial and/or colloidal quantum dots. It provides the beginner with the necessary overview of this exciting field and those more experienced with a comprehensive reference source.
Download or read book Physics Briefs written by and published by . This book was released on 1994 with total page 916 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Introduction to Thin Film Transistors written by S.D. Brotherton and published by Springer Science & Business Media. This book was released on 2013-04-16 with total page 467 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduction to Thin Film Transistors reviews the operation, application and technology of the main classes of thin film transistor (TFT) of current interest for large area electronics. The TFT materials covered include hydrogenated amorphous silicon (a-Si:H), poly-crystalline silicon (poly-Si), transparent amorphous oxide semiconductors (AOS), and organic semiconductors. The large scale manufacturing of a-Si:H TFTs forms the basis of the active matrix flat panel display industry. Poly-Si TFTs facilitate the integration of electronic circuits into portable active matrix liquid crystal displays, and are increasingly used in active matrix organic light emitting diode (AMOLED) displays for smart phones. The recently developed AOS TFTs are seen as an alternative option to poly-Si and a-Si:H for AMOLED TV and large AMLCD TV applications, respectively. The organic TFTs are regarded as a cost effective route into flexible electronics. As well as treating the highly divergent preparation and properties of these materials, the physics of the devices fabricated from them is also covered, with emphasis on performance features such as carrier mobility limitations, leakage currents and instability mechanisms. The thin film transistors implemented with these materials are the conventional, insulated gate field effect transistors, and a further chapter describes a new thin film transistor structure: the source gated transistor, SGT. The driving force behind much of the development of TFTs has been their application to AMLCDs, and there is a chapter dealing with the operation of these displays, as well as of AMOLED and electrophoretic displays. A discussion of TFT and pixel layout issues is also included. For students and new-comers to the field, introductory chapters deal with basic semiconductor surface physics, and with classical MOSFET operation. These topics are handled analytically, so that the underlying device physics is clearly revealed. These treatments are then used as a reference point, from which the impact of additional band-gap states on TFT behaviour can be readily appreciated. This reference book, covering all the major TFT technologies, will be of interest to a wide range of scientists and engineers in the large area electronics industry. It will also be a broad introduction for research students and other scientists entering the field, as well as providing an accessible and comprehensive overview for undergraduate and postgraduate teaching programmes.
Download or read book Organic Solar Cells written by Wallace C.H. Choy and published by Springer. This book was released on 2014-12-14 with total page 0 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.
Download or read book Organic Nanostructures for Next Generation Devices written by Katharina Al-Shamery and published by Springer Science & Business Media. This book was released on 2007-12-29 with total page 369 pages. Available in PDF, EPUB and Kindle. Book excerpt: This jaw-dropping window on the future is the first comprehensive overview of the fabrication, fundamental properties, and applications of a new class of nanoscaled organic materials. These materials offer incredible scope to scientists wanting to exploit their optical and electronic properties and offer the potential to create a new generation of tiny devices with powerful applications. Altogether, the book offers a unique integration of organic materials science basics, nanostructured organic materials fabrication, and device applications.
Download or read book Charge and Energy Transfer Dynamics in Molecular Systems written by Volkhard May and published by John Wiley & Sons. This book was released on 2011-04-27 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt: This 3rd edition has been expanded and updated to account for recent developments, while new illustrative examples as well as an enlarged reference list have also been added. It naturally retains the successful concept of its predecessors in presenting a unified perspective on molecular charge and energy transfer processes, thus bridging the regimes of coherent and dissipative dynamics, and establishing a connection between classic rate theories and modern treatments of ultrafast phenomena. Among the new topics are: - Time-dependent density functional theory - Heterogeneous electron transfer, e.g. between molecules and metal or semiconductor surfaces - Current flows through a single molecule. While serving as an introduction for graduate students and researchers, this is equally must-have reading for theoreticians and experimentalists, as well as an aid to interpreting experimental data and accessing the original literature.
Download or read book Nanoplasmonic Sensors written by Alexandre Dmitriev and published by Springer Science & Business Media. This book was released on 2012-07-31 with total page 394 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a compendium of the finest research in nanoplasmonic sensing done around the world in the last decade. It describes basic theoretical considerations of nanoplasmons in the dielectric environment, gives examples of the multitude of applications of nanoplasmonics in biomedical and chemical sensing, and provides an overview of future trends in optical and non-optical nanoplasmonic sensing. Specifically, readers are guided through both the fundamentals and the latest research in the two major fields nanoplasmonic sensing is applied to – bio- and chemo-sensing – then given the state-of-the-art recipes used in nanoplasmonic sensing research.
Download or read book Photon Management in Solar Cells written by Ralf B. Wehrspohn and published by John Wiley & Sons. This book was released on 2015-06-08 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by renowned experts in the field of photon management in solar cells, this one-stop reference gives an introduction to the physics of light management in solar cells, and discusses the different concepts and methods of applying photon management. The authors cover the physics, principles, concepts, technologies, and methods used, explaining how to increase the efficiency of solar cells by splitting or modifying the solar spectrum before they absorb the sunlight. In so doing, they present novel concepts and materials allowing for the cheaper, more flexible manufacture of solar cells and systems. For educational purposes, the authors have split the reasons for photon management into spatial and spectral light management. Bridging the gap between the photonics and the photovoltaics communities, this is an invaluable reference for materials scientists, physicists in industry, experimental physicists, lecturers in physics, Ph.D. students in physics and material sciences, engineers in power technology, applied and surface physicists.
Download or read book Trends in Chemistry of Materials written by C. N. R. Rao and published by World Scientific. This book was released on 2008 with total page 635 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this collection, the author has compiled a set of his papers representing some of the highlights of materials chemistry. It features a section on oxidic materials, which includes high-temperature superconductivity, colossal magnetoresistance, electronic phase separation and multiferroics. The author has also included novel methods for making gallium nitride, boron nitride and such materials, by using precursors and the urea decomposition route. Moreover, there is a section dealing with open-framework and hybrid materials of which the latter has a great future since one can make use of the rigidity of inorganic structures and the functionality and flexibility of the organic residues to design materials with novel properties.
Download or read book Electronic Properties of Materials written by Rolf E. Hummel and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 323 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present book on electrical, optical, magnetic and thermal properties of materials is in many aspects different from other introductory texts in solid state physics. First of all, this book is written for engineers, particularly materials and electrical engineers who want to gain a fundamental under standing of semiconductor devices, magnetic materials, lasers, alloys, etc. Second, it stresses concepts rather than mathematical formalism, which should make the presentation relatively easy to understand. Thus, this book provides a thorough preparation for advanced texts, monographs, or special ized journal articles. Third, this book is not an encyclopedia. The selection oftopics is restricted to material which is considered to be essential and which can be covered in a 15-week semester course. For those professors who want to teach a two-semester course, supplemental topics can be found which deepen the understanding. (These sections are marked by an asterisk [*]. ) Fourth, the present text leaves the teaching of crystallography, X-ray diffrac tion, diffusion, lattice defects, etc. , to those courses which specialize in these subjects. As a rule, engineering students learn this material at the beginning of their upper division curriculum. The reader is, however, reminded of some of these topics whenever the need arises. Fifth, this book is distinctly divided into five self-contained parts which may be read independently.
Download or read book Organic Spintronics written by Zeev Valy Vardeny and published by CRC Press. This book was released on 2010-04-09 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: Major development efforts in organic materials research has grown for an array of applications. Organic spintronics, in particular, has flourished in the area of organic magneto-transport. Reflecting the main avenues of advancement in this arena, this volume explores spin injection and manipulation in organic spin valves, the magnetic field effect in organic light-emitting diodes (OLEDs), the spin transport effect in relation to spin manipulation, organic magnets as spin injection electrodes in organic spintronics devices, the coherent control of spins in organic devices using the technique of electronically detected magnetic resonance, and the possibility of using organic spin valves as sensors.
Download or read book Organic Conductors written by Jean-Pierre Farges and published by CRC Press. This book was released on 2022-09-16 with total page 874 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work examines all aspects of organic conductors, detailing recent theoretical concepts and current laboratory methods of synthesis, measurement, control and analysis. It describes advances in molecular-scale engineering, including switching and memory systems, Schottky and electroluminescent diodes, field-effect transistors, and photovoltaic devices and solar cells.
