Download or read book Morphology of Bulk Heterojunction Materials in Polymer Based Solar Cells written by Wanli Ma and published by . This book was released on 2006 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solar cell technology based on conjugated polymer/fullerene composites continues to be of interest as a potential source of renewable energy. By applying rigorous fabrication conditions and postproduction annealing at 150°C, polymer solar cells with 5% power conversion efficiency are demonstrated. These devices exhibit remarkable thermal stability. We attribute the improved performance to morphology changes in the bulk heterojunction material induced by thermal annealing.
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 Polymeric Solar Cells written by Frederik C. Krebs and published by DEStech Publications, Inc. This book was released on 2010 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: Book offers a comprehensive treatment of nonhybrid polymeric solar cells from the basic chemistry of donor and acceptor materials through device design, processing and manufacture. Written by a team of Europe-based experts, the text shows the steps and strategies of successfully moving from the science of solar cells to commercial device production. Chapters focus on technologies that lead to increased efficiencies, longer usable life and lower costs. Highlighted are ways to fabricate solar cells from a range of polymers and develop them into marketable commodities. Special consideration is given to solar cells as intellectual property.
Download or read book Optimizing Morphology of Bulk Heterojunction Polymer Solar Cells written by Jing Gao and published by . This book was released on 2014 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: The performance of bulk heterojunction polymer solar cells is profoundly influenced by the spatial arrangements of microstructure at various length scales in its photo-active layer, referred to as morphology. Due to their complex chemical structures, polymers usually exhibits low crystallinity and carrier mobility, leading to a limited thickness ~100 nm of the active layer for a typical polymer solar cell. Such thin films are incompatible with the prevailing large-area coating techniques, thus increasing the difficulty to realize the high-throughput production of polymer-based photovoltaics in industry. On the other hand, for most high-performance low-band-gap polymers, during their film-casting process, processing solvent additives are usually essential for morphology optimization, which help boost device efficiency. However, most commonly-used solvent additives such as 1, 8-Diiodooctane (DIO), are disturbingly reactive to oxygen or water in air, leading to deteriorated performance of devices made under the ambient environment. Therefore, fabrication processes involving DIO have to be limited to an air-free environment, which is quite unfavorable for large-area fabrication techniques, as majority of them are carried on under the ambient environment. Therefore, an efficient air-stable solvent additive would be greatly appreciated in terms of OPV industrialization. As a result, in order to achieve thick active layers as well as to find an air-stable alternative additive for industrial applications, a thorough and systematic study on morphology is necessitated. First, via rational modification of polymer chemical structure(fine-tuning on side chains), new polymers with enhanced structure order (e.g., crystallite size increases from 35 Å to 53 Å) and higher hole mobility (from ~10-5 to ~10-4 cm2/(V*s)) are obtained, enabling thicker optimum active layers ~200 nm with a larger thickness tolerance up to ~350 nm for the corresponding bulk heterojunction devices. This result is of great potential for relaxing the required level of precision in active layer thickness, which has important industrial implications for large-area film deposition. Second, through examining those solvents with a great potential to satisfy the criteria for efficient additives, a new efficient air-stable solvent additive -1,2-dichlorobenzene (DCB) was successfully found for the Diketopyrrolopyrrole-based narrow bandgap polymer under investigation in this work, with a much larger working operation window (up to 80%) and higher device efficiency than DIO. The reason for improved performance lies in higher hole mobility due to polymer crystallinity enhancement in films cast from solution processed by both additives, as demonstrated by Transmission Electron Microscopy (TEM), photoluminescence (PL) and Grazing Incident Wide Angle X-ray Scattering (GIWAXS) results. Small Angle Neutron Scattering (SANS) and UV-visible absorption spectroscopy were also conducted on polymer structures in solution, and their results revealed a novel working mechanism of DCB for morphology control, which involves the modified solution-stage polymer conformations due to the polymer-additive interaction. Upon incorporating DCB into blend solution, the resultant polymer configurations in solution would have a high tendency to preserve into crystalline regions in the as-cast films and this unique way of tuning thin-film morphology via altering polymer conformations in solution has established a new guide for future additive selection in other polymer systems. Results of this manuscript will resolve the current obstacle for high-throughput process in industry and should be of great potential to contribute to practical OPV applications in the near future.
Download or read book Morphology Studies of Polymer Bulk Heterojunction Solar Cells written by Ji Sun Moon and published by . This book was released on 2011 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis is a study of the morphology of polymer:fullerene BHJ, one of the most critical and challenging parts of high efficiency polymer solar cells. To discover the morphology, cross-section as well as top-down transmission electron microscopy were used. The contrast was achieved by utilizing phase contrast microscopy. Thermal annealing, dependence of BHJ thickness, processing additives, solution sequential process and solution sequential process with the use of cosolvent that affects/controls the BHJ morphology are studied in detail.
Download or read book Elementary Processes in Organic Photovoltaics written by Karl Leo and published by Springer. This book was released on 2016-12-20 with total page 423 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents the results of a multi-year research programme funded by the Deutsche Forschungsgemeinschaft (German Research Council), which explains how organic solar cells work. In this new promising photovoltaic technology, carbon-based materials are deposited by low-cost methods onto flexible substrates, thus allowing devices which open completely new applications like transparent coatings for building, solar cells integrated into clothing or packages, and many more. The investigation of organic solar cells is an interdisciplinary topic, covering physics, chemistry and engineering. The different chapters address topics ranging from the synthesis of new organic materials, to the characterization of the elementary processes such as exciton transport and separation, and the principles of highly efficient device design. /div
Download or read book Process structure property relationship of polymer fullerene bulk heterojunction films for organic solar cells written by Benjamin Schmidt-Hansberg and published by Cuvillier Verlag. This book was released on 2012-05-09 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: Photovoltaic (PV) is attracting increasing interest as an important contribution to renewable energy supply. Organic photovoltaic (OPV) is a comparable young PV technology with a great potential towards low cost solar power. This is due to the intrinsic advantage of the incorporated organic semiconductors which are soluble. Solution processing allows high throughput coating and printing processes. Hence, energy intensive high temperature and vacuum steps can be avoided which reduces the fabrication costs and keeps energy payback times low. The performance of organic solar cells strongly depends on the structure of the solution cast photoactive layer which comprises a polymer-fullerene blend. The blend structure evolves during the film drying step which has been studied in this thesis. Starting point of this work was the hypothesis that drying process parameters are suitable for systematically tuning the structure formation during drying of solution cast polymer-fullerene films in order to generate optimized structures with improved photovoltaic performance. For the evaluation of this hypothesis the structure formation of the polymer-fullerene system Poly(3-hexylthiophene-2,5-diyl):[6,6]-Phenyl C61-butyric acid methyl ester (P3HT:PCBM) was investigated incorporating i) thin film drying kinetics, ii) phase behavior of polymer-fullerene solutions, iii) structure formation and iv) the drying process-structure-property relationship of solar cells. The generality of the obtained results has been studied in comparison with the behavior of Poly{[4,40-bis(2-ethylhexyl)dithieno(3,2-b;20,30-d)silole]-2,6-diyl-alt-(2,1,3-benzothidiazole)-4,7-diyl} (PSBTBT). i) Within this thesis a dedicated coating and drying setup was developed which afforded precisely defined coating and drying process conditions as prerequisite for all obtained results. For the first time, the drying behavior of finally a few hundred nanometer thin films could be investigated at five measurement positions with laser reflectometry simultaneously. This allowed the elaboration of a spatially resolved numerical thin film drying model. ii) In conjunction with the measurement and simulation of the evolution of film composition it was required to determine important instants of phase transitions such as solubility limits. Therefore the binodal region of P3HT solutions has been determined in the temperature range of 0°C-60°C. Within the unstable region P3HT solutions phase separate into a sol and a gel phase. The fullerene PCBM exhibits only a single solubility limit. iii) In order to correlate the expected phase transitions according to the phase diagrams with the real structure formation, the above mentioned coating and drying setup was combined with synchrotron based in situ grazing incidence X-ray diffraction (GIXD) measurements. This gave unique insights into the mechanisms and dynamics of polymer-fullerene blend crystallization. After reaching P3HT solubility the crystallization proceeded with well-oriented interface-induced P3HT nucleation followed by P3HT crystal growth with increasing orientation distribution of the crystallites and PCBM aggregation in the final drying period. Furthermore strong polymer-fullerene interaction forces could be derived. By increasing the PCBM fraction it could be shown for the 1:2 P3HT:PCBM ratio that PCBM molecules brake the (020) π-π-stacking of P3HT lamellae which signifies a dramatic loss of hole mobility and consequently reduced device performance. It is further notable that increasing drying temperatures reduce the amount of (020) π-π-stacked P3HT molecules but lead to an increased amount of P3HT (100) crystallinity. Hence, drying temperature determines the preferred direction of crystal growth. iv) Besides a finer degree of phase separation, reduced drying temperatures also cause a higher amount of π-π-stacked polymers, longer effective polymer conjugation length, increased amount of vertical charge transport pathways and an increasingly rough topography due to larger polymer aggregates. Jointly this leads to improved power conversion efficiency at lower drying temperatures. Based on the elaborated knowledge a strategy for a 40% reduction of drying time with only small drawbacks in solar cell performance could be developed. Finally it was important to investigate the transferability of the obtained knowledge to other material systems. PSBTBT:PC71BM blends show similarities to that of P3HT:PCBM with partly interface induced polymer nucleation and subsequent fullerene aggregation in the final drying stage. The kinetics of molecular ordering however proceed fast enough such that the drying process under the investigated conditions cannot limit the structure formation. Hence, P3HT:PCBM is a suitable model system due to its sensitivity to many process parameters. According to the process influence on novel materials the results of this thesis can serve as a source for appropriate process strategies.
Download or read book Controlled Morphology in Bulk Heterojunction Polymer and Perovskite Solar Cells written by Yan Sun and published by . This book was released on 2016 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bulk heterojunction (BHJ) polymer solar cells constitute an emerging approach to a low cost, solution processable, and highly scalable renewable energy avenue. However, one of the major challenges limiting the broad applicability of these solar cells is their lower device efficiencies compared to their inorganic counterparts. In this regard, much effort has been dedicated to optimizing the efficiencies by developing new high-performance materials and fine tuning the BHJ blend morphology via various processing methods. This study presents a molecular level understanding of what controls the device performance.In the first part, a novel fulleropyrrolidine derivative C60-fused N-(3-methoxypropyl)-2-(carboxyethyl)-5-(4-cyanophenyl) fulleropyrrolidine (NCPF) was synthesized and blended with a conjugated polymer poly(3-hexylthiophene) (P3HT) for applications of BHJ polymer solar cells. NCPF has a good solubility in common organic solvents and comparable electronic properties with the widely used acceptor [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). A short term thermal annealing induced enhancement in device performance was found to be associated with improved crystallization of polymer within blend thin films and correspondingly increased hole mobility. The long term annealing study showed that P3HT:NCPF blends had superior thermal stability compared to P3HT:PCBM blends. In the second part, we demonstrate the compatibilization effect of a rod-coil block copolymer (BCP) in different polymer:fullerene derivative blend systems. AFM results and GIWAXS analyses revealed that the addition of BCP into the blend thin films effectively altered the thin film nanostructure and polymer crystalline structure. Moreover, higher device efficiencies were obtained in blends containing block copolymer compatibilizer. The improvement in performance was then ascribed to the morphological changes in the polymer:fullerene blends.The final study deals with the application of a simple, high throughput and roll-to-roll compatible process, zone annealing, to process polymer:fullerene BHJ blends. By morphological study, we established a regime in which interpenetrating phase separated morphology was obtained via zone annealing that exhibited no overgrown fullerene crystallites. Moreover, we extend the use of zone annealing method to perovskite materials, i.e. inorganic--organic hybrid lead halide perovskites. The zone annealed perovskite film morphology exhibits a transition from densely packed structures to dendritic crystallizations with increasing sample annealing velocity. This transition shifts to lower speed in higher temperature condition. By varying temperature and the sweeping speed, large grains were observed in zone annealed samples. Collectively, these studies provide a more fundamental and deeper understanding of the relationships between materials, processing, morphology and performance of thin film solar cells.
Download or read book Morphology Characterization of Low Band Gap Polymer based Organic Photovoltaics written by Feng Liu and published by . This book was released on 2014 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: In bulk heterojunction (BHJ) thin film organic photovoltaics (OPV), morphology control is critical to obtain good device efficiency. Nanoscale phase separation that creates bicontinuous interpenetrating structure on a size scale commensurate with exciton diffusion length (~10 nm) is thought to be the ideal morphology. Results obtained from this work indicate that morphology can be affected by chemical structure of the polymer, processing conditions, blending ratio and post treatments. Physical properties of the material, such as crystallinity, crystal orientation, material interactions and miscibility, surface energy and particle aggregations are critical for determining the morphology and thus the device performance. Previous investigations on poly(3-hexylthiophene) (P3HT) based OPV study yielded a solid structure-property relation. However, different physical properties of polymers preclude the direct transfer of P3HT knowledge to better-performing low band gap polymer OPVs, for which the morphology is directly obtained from solvent casting. This thesis discovered commonalities of low band gap polymer based OPVs. Two important photoactive polymers (PTB7 and DPP) are chosen, each with specific properties. In particular, the function of additives in morphology controls was investigated. Fibril formation at the ~10 nanometer scale proved crucial for obtaining high performance in solar cells. Besides these typical crystalline structures, mixed regions also proved important. The mesh size of the fibril network largely determined the current of the device, and thus determined the power conversion efficiency. The aggregation behavior of polymer chains also influenced the BHJ morphology. Besides the fibril network picture, we also observed multi-length scaled morphology in PTB7 based OPV systems.
Download or read book Nanomorphology Control and Novel Materials Studies in Polymer fullerene Bulk Heterojunction Solar Cells written by Yan Yao and published by . This book was released on 2008 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Controlling the Morphology of Solution processed Bulk Heterojunction Photovoltaics written by Kevin Andrew Sivula and published by . This book was released on 2007 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Semiconducting Polymers written by Georges Hadziioannou and published by John Wiley & Sons. This book was released on 2006-12-15 with total page 786 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of semiconducting polymers has attracted many researchers from a diversity of disciplines. Printed circuitry, flexible electronics and displays are already migrating from laboratory successes to commercial applications, but even now fundamental knowledge is deficient concerning some of the basic phenomena that so markedly influence a device's usefulness and competitiveness. This two-volume handbook describes the various approaches to doped and undoped semiconducting polymers taken with the aim to provide vital understanding of how to control the properties of these fascinating organic materials. Prominent researchers from the fields of synthetic chemistry, physical chemistry, engineering, computational chemistry, theoretical physics, and applied physics cover all aspects from compounds to devices. Since the first edition was published in 2000, significant findings and successes have been achieved in the field, and especially handheld electronic gadgets have become billion-dollar markets that promise a fertile application ground for flexible, lighter and disposable alternatives to classic silicon circuitry. The second edition brings readers up-to-date on cutting edge research in this field.
Download or read book Polymer polymer blends in organic photovoltaic and photodiode devices written by Yuxin Xia and published by Linköping University Electronic Press. This book was released on 2019-01-04 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic photovoltaics devices (OPV) have attracted attentions of scientist for their potential as inexpensive, lightweight, flexible and suitable for roll-to-roll production. In recent years, considerable attention has been focused on new acceptor materials, either polymeric or small molecules, to replace the once dominating fullerene derivatives. The emergence of numerous new non-fullerene materials has driven power conversion efficiency (PCE) up to 17%, attracting more and more interests of commercialization. Polymer acceptors with more morphology stability, more absorption and more desired energy levels has been intensively studied and show great potential for large area and low-cost production in the future. OPV at this moment is not yet competitive with inorganic solar cells in PCE but is more attractive in flexibility, low weight and semitransparency. In this thesis, some basic knowledges of OPV is introduced in the first few chapters, while the next chapters are focusing on polymer-polymer blends and investigating novel structures and techniques for large scale production of solar cells and photodetectors aiming at maximizing these advantages to compete with inorganic counterpart. Thermal annealing effects on polymer-polymer solar cells based is studied. Annealed devices show doubled power conversion efficiency compared to non-annealed devices. Based on the morphology—mobility examination, we conclude that the better charge transport is achieved by higher order and better interconnected networks of the bulk heterojunction in the annealed active layers. The annealing improves charge transport and extends the conjugation length of the polymers, which do help charge generation and meanwhile reduce recombination. The blend of an amorphous polymer and a semi-crystalline polymer can thus be modified by thermal annealing to double the power conversion efficiency. A novel concept of all-polymer organic photovoltaics device is demonstrated in this thesis where all the layers are made out of polymers. We use PEDOT:PSS as semitransparent anode and polyethyleneimine modified PEDOT:PSS as semitransparent cathode, both of which are slot-die printed on polyethylene terephthalate(PET). Active layers are deposited on cathode and anode surfaces by spin coating separately. These layers are then joined through a roll-to-roll compatible lamination process. This forms a semitransparent and flexible solar cell. By laminating a thin layer acceptor polymer to a thick polymer-polymer blend, we can further improve the performance by reducing traps comparing to laminating blend to blend. Flexible and semitransparent all-polymer photodiodes with different geometries can be fabricated through lamination. By choosing high band gap polymers and appropriate combination of two or more polymers, organic photodiode with low noise and high specific detectivity can be obtained. Comparison between bilayer and bulk heterojunction devices gives better understanding of the origin of noise and provides ways to improve the performance of photodiodes as detector. Noise level is a critical parameter for photodetectors. The difficulties of measuring the noise of photodetectors make some researchers prefer the estimated shot noise as the dominating one and ignore the thermal noise and 1/f noise. The latter two terms are sometimes several orders higher than the former, noting the importance of experimentally measuring noise. The use of semi-transparent photovoltaic devices causes an inevitable loss of photocurrent, as light transmitted has not been absorbed. This trivial effect also leads to a loss of photovoltage, an effect partially due to the lower photocurrent but also due to the geometry of the semitransparent photovoltaic device. We here demonstrate and evaluate this photovoltage loss in semi-transparent organic photovoltaic devices, compared with non-transparent solar cells of the same material. Semi-transparent solar cells in addition introduce photovoltage loss when formed by lamination. We document and analyze these effects for a number of polymer blends in the form of bulk heterojunctions.
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 In Situ Morphology Control of P3HT PC61BM Bulk Heterojunction BHJ Polymer Solar Cells written by Jaewook Seok and published by . This book was released on 2012 with total page 175 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Flexible Solar Cells written by Mario Pagliaro and published by John Wiley & Sons. This book was released on 2008-11-21 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the decline in the world's natural resources, the need for new and cheaper energy sources is evolving. One such source is the sun which generates heat and light which can be harnessed and used to our advantage. This reference book introduces the topic of photovoltaics in the form of flexible solar cells. There are explanations of the principles behind this technology, the engineering required to produce these products and the future possibilities offered by this technology. The chemistry and physics of the cells (both organic and inorganic) are clarified as well as production methods, with information how this can then be applied to the nanoscale as well. A complete guide to this new and exciting way of producing energy which will be invaluable to a variety of people from material scientists, chemists, electrical engineers, to management consultants and politicians.
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.
