Download or read book Binary and Ternary Bulk Heterjunction Solar Cells with Alternative Donor to acceptor Ratios written by Hang Yin and published by . This book was released on 2017 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bulk heterojunction (BHJ) organic photovoltaic (OPV) is one of the most promising techniques to generate electricity with advantages of flexibility, solution processing and capability for large area device fabrication. Although the power conversion efficiency (PCE) of BHJ solar cells has already achieved over 13%, there are still problems remain to be solved. This thesis presents the binary and ternary organic BHJ devices with alternative donor:acceptor (D:A) ratios, and the charge transport properties and electronic interactions in their BHJ films. In a high performance BHJ solar cell, the commonly optimized D:A weight ratio is about 1:x, where x is commonly in excess of 1.5, when PC71BM is used as the acceptor. We demonstrated how to achieve high PCEs of BHJ solar cells by enriching the D:A weight ratios. The PCEs of the re-optimized cells were improved for the PTB7:PC71BM, PCDTBT:PC71BM, PDTSTPD:PC71BM devices. Current-voltage (JV) and admittance spectroscopy (AS) measurements indicate enhanced hole mobilities for the polymer-rich BHJs based on PTB7, PCDTBT, and PDTSTPD. At the same time, although the relative weight ratio of PC71BM is reduced, the electron mobilities are maintained due to the dispersion of fullerene domains by increased DIO concentrations. The active layer thickness of most optimized BHJ solar cells is about 100nm. The thin active layer is unfavorable for optical absorption and film coating. We employed a ternary strategy to address this problem, and the thick-film BHJ devices can retain 90% PCEs of their optimized thin-film devices. Three model systems were studied, involving PTB7:PC71BM, PTB7-Th:PC71BM and P3HT:PCBM BHJs. Into these BHJs, a ternary component, p-DTS(fbtth2)2 (DTS) is introduced. With DTS, the corresponding thick film devices have significantly improved PCEs. The ternary component DTS improves hole mobility and reduces sub-bandgap trap states. Both observations are well correlated with improved FFs of the ternary BHJ cells. Photothermal deflection spectroscopy (PDS) and 1H nuclear magnetic resonance (1H NMR) results indicate that DTS behaves as conducting bridges in between two neighboring polymer segments. Most lab-based BHJ solar cells are optimized by their power conversion efficiencies (PCEs). We challenge this conventional view by showing that BHJ cells using fullerene acceptors should be optimized by their fill-factors (FFs). With the optimized-FF approach, BHJ cells tend to have higher fullerene content when compared to the BHJ cells that are optimized by PCEs. The FF-optimized BHJ cells have slightly reduced PCEs (due to smaller Jscs) compared to the PCE-optimized cells. Yet, FF-optimized cells enjoy a much better thermal stability. We demonstrate that these FF-optimized BHJs possess better-balanced electron-to-hole mobility ratios due to weakly field-dependent electron mobilities. The improved mobility ratio suppresses carrier recombination. Our results suggest that BHJ cells optimized by their PCEs should be meta-stable, and other D:A ratios should be considered for practical BHJ cell development.
Download or read book Novel Acceptor Molecules for Bulk Heterojunction Organic Solar Cells written by Jason Thomas Bloking and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Solution-processable organic solar cells offer the promise of clean energy generation at lower cost than conventional technologies due to high-throughput roll-to-roll manufacturing, cheap and abundant materials and the lower installation costs associated with lightweight and flexible solar modules. Power conversion efficiencies of organic solar cells have surpassed 10% due in large part to the discovery and design of new materials for the donor half of the donor-acceptor heterojunction. However, the vast majority of organic photovoltaic devices contain fullerene derivatives as the electron acceptor material. Devices containing fullerenes as the electron acceptors have been shown to be energetically limited to open-circuit voltages of 1.0 V or less, thus limiting their maximum efficiency and potential for use as the high-voltage top cell in tandem solar cell architectures. This is in addition to other drawbacks of fullerenes such as their high synthetic cost and relatively poor light absorption. A phenyl imide-based electron acceptor molecule, HPI-BT, has been developed as an alternative to fullerene derivatives to address some of these drawbacks. Device efficiencies of up to 3.7% with the common electron donating polymer poly (3-hexyl thiophene) -- P3HT -- have been achieved through detailed optimization. While these devices have open-circuit voltages of 0.94 V (0.31 V higher than comparable devices with P3HT and PC61BM, a common fullerene derivative), the quantum efficiency is 20% lower than the equivalent fullerene-containing device. Through investigation of the dependence of quantum efficiency on applied electric field and light intensity in these devices and others using additional electron donating polymers, the primary cause of lower quantum efficiency in these devices is found to be recombination of geminate charge pairs before they are able to reach their fully charge-separated state. Recent research reports show that the microstructure of a typical bulk heterojunction organic solar cell consists of a relatively pure electron donor phase (P3HT), a relatively pure acceptor phase (PC61BM) and a two-component mixed phase at the interface of the two pure phases. This interfacial mixed phase is believed to provide an energetic driving force for charge separation from the mixed phase into the pure phases, thus providing high quantum efficiencies in fullerene-based devices. X-ray diffraction studies on blends of polythiophene and HPI-BT show no evidence of a strongly mixed third phase. The lower quantum efficiency of devices containing HPI-BT without this third mixed phase is explained by the favorable energetic offsets created in this three-phase morphology. Alternatively, the inability of fullerenes to effectively absorb light can be partially mitigated by the addition of a third molecule providing additional absorption bandwidth in a ternary blend organic solar cell. The addition of up to 20% (by weight) of a conjugated dye molecule, tetra-tert-butyl functionalized silicon naphthalocyanine (t-butyl SiNc), to a typical bulk heterojunction solar cell with P3HT and PC61BM results in the generation of additional photocurrent from dye absorption in the near-infrared region of the light spectrum. The effect of the tert-butyl functionalization on the incorporation of the dye molecule is discussed along with the potential for improved efficiency of ternary blend organic solar cells relative to their binary blend counterparts.
Download or read book Binary and Ternary Molecules Blend Bulk Heterojunction Organic Solar Cell written by Emmanuel Khulekani Mkhwanazi and published by . This book was released on 2015 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 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 Physics of Solar Cells written by Peter Würfel and published by John Wiley & Sons. This book was released on 2008-07-11 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: Peter Würfel describes in detail all aspects of solar cell function, the physics behind every single step, as well as all the issues to be considered when improving solar cells and their efficiency. Based on the highly successful German version, but thoroughly revised and updated, this edition contains the latest knowledge on the mechanisms of solar energy conversion. Requiring no more than standard physics knowledge, it enables readers to understand the factors driving conversion efficiency and to apply this knowledge to their own solar cell development.
Download or read book Inorganic Ternary Thin Films Anaysis of Optical Properties written by Cliff Orori Mosiori and published by Anchor Academic Publishing (aap_verlag). This book was released on 2015 with total page 225 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thin films can be used to fabricate optoelectronic devices. Technology is currently focusing on ternary thin film composition because of their structure, inter-band transitions and other optical properties that can be maximized. This book discusses in detail the optical characteristics of ternary thin films and further investigates the behavior of Iron Zinc Sulphide, Lead Silver Sulphide, Copper Silver Sulphide, Copper Zinc Sulphide and Cadmium Zinc Sulphide. Thin films are of fundamental importance in modern technology.
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 Materials Concepts For Solar Cells Second Edition written by Thomas Dittrich and published by World Scientific Publishing Company. This book was released on 2018-01-30 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt: A modern challenge is for solar cell materials to enable the highest solar energy conversion efficiencies, at costs as low as possible, and at an energy balance as sustainable as necessary in the future. This textbook explains the principles, concepts and materials used in solar cells. It combines basic knowledge about solar cells and the demanded criteria for the materials with a comprehensive introduction into each of the four classes of materials for solar cells, i.e. solar cells based on crystalline silicon, epitaxial layer systems of III-V semiconductors, thin-film absorbers on foreign substrates, and nano-composite absorbers. In this sense, it bridges a gap between basic literature on the physics of solar cells and books specialized on certain types of solar cells.The last five years had several breakthroughs in photovoltaics and in the research on solar cells and solar cell materials. We consider them in this second edition. For example, the high potential of crystalline silicon with charge-selective hetero-junctions and alkaline treatments of thin-film absorbers, based on chalcopyrite, enabled new records. Research activities were boosted by the class of hybrid organic-inorganic metal halide perovskites, a promising newcomer in the field.This is essential reading for students interested in solar cells and materials for solar cells. It encourages students to solve tasks at the end of each chapter. It has been well applied for postgraduate students with background in materials science, engineering, chemistry or physics.
Download or read book Advances in Materials Development written by B.S. Sunder Daniel and published by Trans Tech Publications Ltd. This book was released on 2012-12-27 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: Special topic volume with invited peer reviewed papers only.
Download or read book Printable Solar Cells written by Nurdan Demirci Sankir and published by John Wiley & Sons. This book was released on 2017-04-19 with total page 578 pages. Available in PDF, EPUB and Kindle. Book excerpt: Printable Solar Cells The book brings together the recent advances, new and cutting edge materials from solution process and manufacturing techniques that are the key to making photovoltaic devices more efficient and inexpensive. Printable Solar Cells provides an overall view of the new and highly promising materials and thin film deposition techniques for printable solar cell applications. The book is organized in four parts. Organic and inorganic hybrid materials and solar cell manufacturing techniques are covered in Part I. Part II is devoted to organic materials and processing technologies like spray coating. This part also demonstrates the key features of the interface engineering for the printable organic solar cells. The main focus of Part III is the perovskite solar cells, which is a new and promising family of the photovoltaic applications. Finally, inorganic materials and solution based thin film formation methods using these materials for printable solar cell application is discussed in Part IV. Audience The book will be of interest to a multidisciplinary group of fields, in industry and academia, including physics, chemistry, materials science, biochemical engineering, optoelectronic information, photovoltaic and renewable energy engineering, electrical engineering, mechanical and manufacturing engineering.
Download or read book Polymer Photovoltaics written by Fei Huang and published by Royal Society of Chemistry. This book was released on 2016 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt: An international perspective on the latest research in polymer solar cell technology.
Download or read book Principles of Solar Cells LEDs and Diodes written by Adrian Kitai and published by John Wiley & Sons. This book was released on 2011-09-13 with total page 333 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The book will cover the two most important applications of semiconductor diodes - solar cells and LEDs - together with quantitative coverage of the physics of the PN junction at the senior undergraduate level. It will include: Review of semiconductor physics Introduction to PN diodesThe solar cell Physics of efficient conversion of sunlight into electrical energy Semiconductor solar cell materials and device physics Advanced solar cell materials and devices The light emitting diode Physics of efficient conversion of electrical energy into light Semiconductor light emitting diode materials and device physics Advanced light emitting diode materials and devices"--
Download or read book Solid State Properties written by Mildred Dresselhaus and published by Springer. This book was released on 2018-01-17 with total page 521 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book fills a gap between many of the basic solid state physics and materials sciencebooks that are currently available. It is written for a mixed audience of electricalengineering and applied physics students who have some knowledge of elementaryundergraduate quantum mechanics and statistical mechanics. This book, based on asuccessful course taught at MIT, is divided pedagogically into three parts: (I) ElectronicStructure, (II) Transport Properties, and (III) Optical Properties. Each topic is explainedin the context of bulk materials and then extended to low-dimensional materials whereapplicable. Problem sets review the content of each chapter to help students to understandthe material described in each of the chapters more deeply and to prepare them to masterthe next chapters.
Download or read book Fundamentals of Solar Cell Design written by Inamuddin and published by John Wiley & Sons. This book was released on 2021-08-24 with total page 578 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solar cells are semiconductor devices that convert light photons into electricity in photovoltaic energy conversion and can help to overcome the global energy crisis. Solar cells have many applications including remote area power systems, earth-orbiting satellites, wristwatches, water pumping, photodetectors and remote radiotelephones. Solar cell technology is economically feasible for commercial-scale power generation. While commercial solar cells exhibit good performance and stability, still researchers are looking at many ways to improve the performance and cost of solar cells via modulating the fundamental properties of semiconductors. Solar cell technology is the key to a clean energy future. Solar cells directly harvest energy from the sun’s light radiation into electricity are in an ever-growing demand for future global energy production. Solar cell-based energy harvesting has attracted worldwide attention for their notable features, such as cheap renewable technology, scalable, lightweight, flexibility, versatility, no greenhouse gas emission, environment, and economy friendly and operational costs are quite low compared to other forms of power generation. Thus, solar cell technology is at the forefront of renewable energy technologies which are used in telecommunications, power plants, small devices to satellites. Aiming at large-scale implementation can be manipulated by various types used in solar cell design and exploration of new materials towards improving performance and reducing cost. Therefore, in-depth knowledge about solar cell design is fundamental for those who wish to apply this knowledge and understanding in industries and academics. This book provides a comprehensive overview on solar cells and explores the history to evolution and present scenarios of solar cell design, classification, properties, various semiconductor materials, thin films, wafer-scale, transparent solar cells, and so on. It also includes solar cells’ characterization analytical tools, theoretical modeling, practices to enhance conversion efficiencies, applications and patents.
Download or read book Chalcogenide Photovoltaics written by Roland Scheer and published by John Wiley & Sons. This book was released on 2011-03-31 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt: This first comprehensive description of the most important material properties and device aspects closes the gap between general books on solar cells and journal articles on chalcogenide-based photovoltaics. Written by two very renowned authors with years of practical experience in the field, the book covers II-VI and I-III-VI2 materials as well as energy conversion at heterojunctions. It also discusses the latest semiconductor heterojunction models and presents modern analysis concepts. Thin film technology is explained with an emphasis on current and future techniques for mass production, and the book closes with a compendium of failure analysis in photovoltaic thin film modules. With its overview of the semiconductor physics and technology needed, this practical book is ideal for students, researchers, and manufacturers, as well as for the growing number of engineers and researchers working in companies and institutes on chalcogenide photovoltaics.
Download or read book Optoelectronic Organic Inorganic Semiconductor Heterojunctions written by Ye Zhou and published by CRC Press. This book was released on 2021-01-19 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optoelectronic Organic-Inorganic Semiconductor Heterojunctions summarizes advances in the development of organic-inorganic semiconductor heterojunctions, points out challenges and possible solutions for material/device design, and evaluates prospects for commercial applications. Introduces the concept and basic mechanism of semiconductor heterojunctions Describes a series of organic-inorganic semiconductor heterojunctions with desirable electrical and optical properties for optoelectronic devices Discusses typical devices such as solar cells, photo-detectors, and optoelectronic memories Outlines the materials and device challenges as well as possible strategies to promote the commercial translation of semiconductor heterojunctions-based optoelectronic devices Aimed at graduate students and researchers working in solid-state materials and electronics, this book offers a comprehensive yet accessible view of the state of the art and future directions.
