Download or read book Exciton Behaviour at Organic Solar Cell Interfaces written by Olivia Dinica and published by . This book was released on 2015 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic photovoltaics (OPVs) have emerged as a promising class of materials in the production of flexible and cheap solar cells. Polymer OPVs are typically composed of a blend of a semiconducting electron donating polymer with an electron accepting fullerene derivative. This blend leads to a high donor-acceptor interfacial surface area where excitons are split apart to create free charges. The generation of free charges after photo-excitation is a main factor influencing solar cell efficiency. However, the mechanisms of charge transfer and the competing process of charge recombination at the interface are not completely clear. The understanding of these processes is essential for the rational design of materials that can maximize photovoltaic conversion efficiencies. The focus of this dissertation is on the influence that electric fields and chemical structure have on exciton issociation and recombination at the interface of donor-acceptor materials. In particular, we use mixed classical dynamical simulations and electronic structure calculations to investigate several oligomer-fullerene systems. In order to study the potential energy surfaces guiding the dynamics of electron transfer, the nuclear and electron dynamics of large systems need to be simulated. To make these calculations computationally feasible, a mixed quantum classical molecular dynamics (MQCMD) approach was taken. This technique is based on the QCFF/PI formalism first described by Warshel and Karplus and was further developed by Lobaugh and Rossky for the simulation of betaine-30. This approach divides the conjugated system into a classical and a quantum subsystem. The quantum treatment is reserved for the [greek small letter pi] electronic system described by the Pariser-Parr-Pople (PPP) Hamiltonian. The classical potential describes a fully flexible molecular backbone and is modeled using an empirical molecular mechanics force field. In the first part of the dissertation we are examining the effect of an external electric field on charge transfer pathways and rates at sexithiophene/fullerene interfaces. In the second part, we develop a rigorous parametrization technique that allows us to model push-pull polymers. These polymers include PCDTBT and KP115 which have a more complex molecular structure than homo-polymers like the one considered in the first part. We use the QCFF/PI method as well as electronic structure calculations to investigate the influence of molecular structure and donor-acceptor orientation on charge transfer and recombination. The pathways linking exciton formation, charge transfer and thermal relaxation are explored, particularly in the context of dependence in the morphology of the donor molecules as well as the non-adiabatic coupling between excited states.
Download or read book On the Exciton Blocking Layer at the Interface Organic cathode in Planar Multiheterojunction Organic Solar Cells written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Organic Solar Cells written by Liming Ding and published by John Wiley & Sons. This book was released on 2022-02-09 with total page 988 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic Solar Cells A timely and singular resource on the latest advances in organic photovoltaics Organic photovoltaics are gaining widespread attention due to their solution processability, tunable electronic properties, low temperature manufacture, and cheap and light materials. Their wide range of potential applications may result in significant near-term commercialization of the technology. In Organic Solar Cells: Materials Design, Technology and Commercialization, renowned scientist Dr. Liming Ding delivers a comprehensive exploration of organic solar cells, including discussions of their key materials, mechanisms, molecular designs, stability features, and applications. The book presents the most state-of-the-art developments in the field alongside fulsome treatments of the commercialization potential of various organic solar cell technologies. The author also provides: Thorough introductions to fullerene acceptors, polymer donors, and non-fullerene small molecule acceptors Comprehensive explorations of p-type molecular photovoltaic materials and polymer-polymer solar cell materials, devices, and stability Practical discussions of electron donating ladder-type heteroacenes for photovoltaic applications In-depth examinations of chlorinated organic and single-component organic solar cells, as well as the morphological characterization and manipulation of organic solar cells Perfect for materials scientists, organic and solid-state chemists, and solid-state physicists, Organic Solar Cells: Materials Design, Technology and Commercialization will also earn a place in the libraries of surface chemists and physicists and electrical engineers.
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.
Download or read book Organic Solar Cells written by Qiquan Qiao and published by CRC Press. This book was released on 2017-12-19 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt: Current energy consumption mainly depends on fossil fuels that are limited and can cause environmental issues such as greenhouse gas emissions and global warming. These factors have stimulated the search for alternate, clean, and renewable energy sources. Solar cells are some of the most promising clean and readily available energy sources. Plus, the successful utilization of solar energy can help reduce the dependence on fossil fuels. Recently, organic solar cells have gained extensive attention as a next-generation photovoltaic technology due to their light weight, mechanical flexibility, and solution-based cost-effective processing. Organic Solar Cells: Materials, Devices, Interfaces, and Modeling provides an in-depth understanding of the current state of the art of organic solar cell technology. Encompassing the full spectrum of organic solar cell materials, modeling and simulation, and device physics and engineering, this comprehensive text: Discusses active layer, interfacial, and transparent electrode materials Explains how to relate synthesis parameters to morphology of the photoactive layer using molecular dynamics simulations Offers insight into coupling morphology and interfaces with charge transport in organic solar cells Explores photoexcited carrier dynamics, defect states, interface engineering, and nanophase separation Covers inorganic–organic hybrids, tandem structure, and graphene-based polymer solar cells Organic Solar Cells: Materials, Devices, Interfaces, and Modeling makes an ideal reference for scientists and engineers as well as researchers and students entering the field from broad disciplines including chemistry, material science and engineering, physics, nanotechnology, nanoscience, and electrical engineering.
Download or read book Perovskite Materials written by Likun Pan and published by BoD – Books on Demand. This book was released on 2016-02-03 with total page 652 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book summarizes the current state of the know-how in the field of perovskite materials: synthesis, characterization, properties, and applications. Most chapters include a review on the actual knowledge and cutting-edge research results. Thus, this book is an essential source of reference for scientists with research fields in energy, physics, chemistry and materials. It is also a suitable reading material for graduate students.
Download or read book Exciton Recombination in the Fullerene Phase of Bulk Heterojunction Organic Solar Cells written by George Frederick Burkhard and published by Stanford University. This book was released on 2011 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt: Finding alternatives to fossil fuel energy sources is necessary to stem global warming, to provide economic and political independence, and to keep up with increasing energy demand. Because of their low cost, flexibility, and because the material resources needed to make them are abundant, organic polymer solar cells are an attractive alternative to conventional solar technology. Organic solar technology has been developing rapidly; however, with the best power conversion efficiencies at ~8%, much improvement is needed before it can be competitive with established solar technologies. Poly-3-hexylthiophene:[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) solar cells are the most studied type of organic solar cell. Nevertheless, their loss mechanisms are still not fully understood. In this work, we study excitonic losses in the PCBM phase of the blend. We develop a way to accurately measure internal quantum efficiencies (IQEs) and use this technique to characterize P3HT:PCBM devices. We observe spectral dependence of the IQE and conclude that a majority of excitons generated in the PCBM are lost to Auger recombination with polarons that are trapped in that phase. We also provide evidence that this process may happen in other materials and may be a critical factor in limiting exciton diffusion in organic semiconductors.
Download or read book Origin of Charge Transfer Exciton Dissociation in Organic Solar Cells written by Shota Ono and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Using a temperature (T)-dependent tight-binding (TB) model for an electron-hole pair at the donor-acceptor (DA) interface, we investigate the dissociation of charge transfer exciton (CTE) into free carriers, that is, an electron and a hole. We observe the existence of the localization-delocalization transition at a critical T, below which the charges are localized to the DA interface, and above which the charges are delocalized over the system. This explains the CTE dissociation observed in organic solar cells. The present study highlights the combined effect of finite T and carrier delocalization in the CTE dissociation.
Download or read book Understanding Exciton Diffusion in Organic Solar Cells written by Amy Illingworth and published by . This book was released on 2012 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Excitons written by Sergei L. Pyshkin and published by . This book was released on 2018 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excitons, as part of the InTech collection of international works on optics and optoelectronics, contains recent achievements of specialists from China, France, Japan, Switzerland, and Moldova jointly with Russia and the United States of America on properties and application of excitons in electronics. The growing number of countries participating in this endeavor and joint participation of the US, Moldova, Italy, and Russian scientists in investigations of excitons in the edition of this book testify to the unifying effect of science. An interested reader will find in the book the description of properties and possible applications of excitons, as well as the methods of fabrication and analysis of operation and the regions of application of modern excitonic devices.
Download or read book Advanced Materials Interfaces written by Ashutosh Tiwari and published by John Wiley & Sons. This book was released on 2016-06-22 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advanced Material Interfaces is a state-of-the-art look at innovative methodologies and strategies adopted for interfaces and their applications. The 13 chapters are written by eminent researchers not only elaborate complex interfaces fashioned of solids, liquids, and gases, but also ensures cross-disciplinary mixture and blends of physics, chemistry, materials science, engineering and life sciences. Advanced interfaces operate fundamental roles in essentially all integrated devices. It is therefore of the utmost urgency to focus on how newly-discovered fundamental constituents and interfacial progressions can be materialized and used for precise purposes. Interfaces are associated in wide multiplicity of application spectrum from chemical catalysis to drug functions and the advancement is funnelled by fine-tuning of our fundamental understanding of the interface effects.
Download or read book Simulations of Organic Solar Cells with an Event driven Monte Carlo Algorithm written by Vincent Paul Robbiano and published by . This book was released on 2011 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt: The generation of photocurrent in organic solar cells starts with a photon being absorbed in the active layer and creating an excited electron/hole pair (exciton). The exciton is mobile and dissociates into electron and hole at an interface between donor and acceptor material, unless it decays before it reaches the interface. If they do not recombine, the charge carriers migrate toward the appropriate electrode and contribute to the photocurrent. Thus, the efficiency of organic solar cells depends strongly on the geometry and electronic properites of the donor/acceptor materials. Simulating in detail the processes described above is of interest since it enables the modeling of devices with different architectures and materials properties. Since processes such as exciton absorption, electron hopping, and recombination take place on vastly different time scales, we employ an event-driven Monte Carlo algotithm to simulate a coarse grained lattice model of the active layer of organic solar cells. We investigate devices of two geometries, one planar and one V-shaped, that differ significantly in the size of the donor/acceptor interface. The trends observed in our results agree with literature findings that show that, as the interface increases, the current density, charge carrier density and internal quantum efficiency of the device also increase.
Download or read book Transient Optical Studies of Exciton Dynamics in Organic Solar Cells written by Luke X. Reynolds and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: There is increasing evidence that the initially generated excited state species in bulk heterojunction solar cell photoactive layers are critical to device performance. At present however, an understanding of the nature and dynamics of such excited states still remains limited. This thesis presents a study of the ultrafast exciton dynamics in bulk heterojunction organic and hybrid organic-inorganic solar cells. Fluorescence upconversion is used to elucidate the dynamics of such transient species allowing internal properties of the blend systems to be probed including changes in film morphology and ultrafast energy loss mechanisms. An understanding of such processes is an important step forward in the evolution of molecular semiconductor based solar cells. The first chapter focuses on the main experimental technique, fluorescence upconversion, and how this can be employed to study excited states. In particular, this section addresses one of the main unanswered questions in the field and attempts to correlate the exciton dynamics with the structure of the common photoactive polymer poly(3-hexylthiophene) (P3HT). Three structural variations of P3HT are studied and their exciton dynamics associated with differing internal processes occurring within the polymers. These include self localisation, and different types of long-range energy transfer mechanisms. The following two chapters build upon the knowledge of exciton dynamics obtained from the first chapter. First, a study is made of amorphous polymers with different acceptors, all based on phenyl-C61-butyric acid methyl ester (PCBM). The distinct interactions of the PCBM-type molecules with the polymer results in different electron transfer dynamics, from which the exciton diffusion length of the polymer in real bulk heterojunction blends is extracted using a simple model. Second, the ultrafast excited state dynamics of a crystalline polymer with the same PCBM-type acceptors is studied. Correlation of these dynamics with thermal analysis of the blend films allows the morphology of the films to be extracted and allows two different mechanisms of microstructure development to be identified. In the final chapter, the effect of acceptor aggregation on exciton dynamics and charge generation yields in hybrid organic-inorganic blend films has been studied. Such aggregation has been shown to be essential for efficient charge generation in all-organic solar cells but has often been assumed to be less important in such inorganic hybrids. More aggregated acceptor nanoparticles are shown to not only result in greater than expected exciton quenching but are also shown to result in a greater yield of long-lived charges. This study is extended to show that in-situ grown inorganic nanoparticles exhibit superior performance to standard pre-synthesised inorganics.
Download or read book Recent Advances in Photovoltaics written by Meera Ramrakhiani and published by Materials Research Forum LLC. This book was released on 2017-10-01 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ever growing demand for clean energy potentially can be met by solar-to-electrical energy conversion. This book on “Recent Advances in Photovoltaics” presents a detailed overview of recent research and developments in the field of photovoltaics and solar cells. It starts with the basic theory and gradual progress in the field of photovoltaics and various generations of solar cells. The search for new materials and/or new structures such as multi-junctions, nanostructures, photoelectrochemical cells, organic solar cells etc. for improved performance is discussed. The experimental investigations on certain materials and modelling for better results are also described in the book. Photovoltaics, Solar Cells, Multi-Junctions Solar Cells, Nanostructured Solar Cells, Photoelectrochemical Solar Cells, Organic Solar Cells, Polymer Solar Cells
Download or read book Solar Fuels written by Theodore Goodson, III and published by CRC Press. This book was released on 2017-04-28 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written for use as a text and reference for those interested in how new materials may be used to capture, store, and use solar energy for alternative energy resources in everyday life, Solar Fuels: Materials, Physics, and Applications discusses the fundamentals of new materials and the physical processes involved in their mechanisms and design. This book offers clear examples of current state-of-the-art organic and inorganic solar cell materials and devices used in the field, and includes experiments testing solar capability along with standardized examples. Last, but not least, it also gives a clear outline of the challenges that need to be addressed moving forward.
Download or read book Colloidal Quantum Dot Optoelectronics and Photovoltaics written by Gerasimos Konstantatos and published by Cambridge University Press. This book was released on 2013-11-07 with total page 329 pages. Available in PDF, EPUB and Kindle. Book excerpt: Captures the most up-to-date research in the field, written in an accessible style by the world's leading experts.
Download or read book Advanced Solar Cell Materials Technology Modeling and Simulation written by Fara, Laurentiu and published by IGI Global. This book was released on 2012-07-31 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: While measuring the effectiveness of solar cell materials may not always be practical once a device has been created, solar cell modeling may allow researchers to obtain prospective analyses of the internal processes of potential materials prior to their manufacture. Advanced Solar Cell Materials, Technology, Modeling, and Simulation discusses the development and use of modern solar cells made from composite materials. This volume is targeted toward experts from universities and research organizations, as well as young professionals interested in pursuing different subjects regarding advanced solar cells.
