Download or read book Performance and Durability of Polymer Solar Cells by Low temperature Drying Process and Hfo2 Blocking Layer written by 林恩詠 and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 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 Stability and Degradation of Organic and Polymer Solar Cells written by Frederik C. Krebs and published by John Wiley & Sons. This book was released on 2012-04-23 with total page 375 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic photovoltaics (OPV) are a new generation of solar cells with the potential to offer very short energy pay back times, mechanical flexibility and significantly lower production costs compared to traditional crystalline photovoltaic systems. A weakness of OPV is their comparative instability during operation and this is a critical area of research towards the successful development and commercialization of these 3rd generation solar cells. Covering both small molecule and polymer solar cells, Stability and Degradation of Organic and Polymer Solar Cells summarizes the state of the art understanding of stability and provides a detailed analysis of the mechanisms by which degradation occurs. Following an introductory chapter which compares different photovoltaic technologies, the book focuses on OPV degradation, discussing the origin and characterization of the instability and describing measures for extending the duration of operation. Topics covered include: *Chemical and physical probes for studying degradation *Imaging techniques *Photochemical stability of OPV materials *Degradation mechanisms *Testing methods *Barrier technology and applications Stability and Degradation of Organic and Polymer Solar Cells is an essential reference source for researchers in academia and industry, engineers and manufacturers working on OPV design, development and implementation.
Download or read book Polymer Solar Cells Molecular Design and Microstructure Control written by Kui Zhao and published by Frontiers Media SA. This book was released on 2020-12-10 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: This eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contact.
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 Improvement of Polymer Solar Cells Through Device Design written by Yechuan Sun and published by . This book was released on 2017-01-26 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Improvement of Polymer Solar Cells Through Device Design" by Yechuan, Sun, 孙也川, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: In this thesis, fabrication of polymer solar cells through different device designs is presented and the resulted solar cell performance is discussed. Poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) are chosen as the photoactive layer materials as this material combination has been widely used and well investigated. The known properties of P3HT and PCBM make systematical studies and modeling for the effect of device designs on the performance of polymer solar cells possible although this is beyond the scope of this thesis. First, ITO electrodes were fabricated by sputtering and used as the transparent electrode for polymer solar cells. Properties of ITO film fabricated by different sputtering conditions were compared. Radio frequency (RF) sputtered ITO was found to exhibit the best transparency overall. This condition was further applied to the fabrication of ITO electrode for polymer solar cells with light trapping structures. Low temperature processed silicon oxide (SiOx) / titanium oxide (TiOx) periodic structures were fabricated by sol-gel method. Optical transmittance of the bottom electrode was altered by the presence of the reflective coating and thus the absorption in the photoactive layer was affected. By varying the number of layer pairs and thickness of each layer in the reflective coating, improvement of polymer solar cell performance was found by inserting reflective coating for optimized conditions. Finally, semi-transparent polymer solar cells with inverted structure were demonstrated using conductive polymer as the anode. The process in device preparation was vacuum-free and thus could be potentially useful in large-scale roll-to-roll fabrication. DOI: 10.5353/th_b4784994 Subjects: Solar cells - Design and construction Conducting polymers
Download or read book Fiber Solar Cells written by Shaocong Hou and published by Springer. This book was released on 2017-01-23 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents the fundamental research and latest findings on novel flexible/wearable photovoltaic technology, and comprehensively summarizes the rapid developments in flexible photovoltaics, from traditional planar solar cells to fiber solar cells. It discusses the rational design of fiber solar cell materials, electrodes and devices, as well as critical factors including cost, efficiency, flexibility and stability . Furthermore, it addresses fundamental theoretical principles and novel fabrication technologies and their potential applications. The book provides practical information for university researchers and graduate students interested in flexible fiber photovoltaics, and inspires them to design other novel flexible/wearable electronics and textiles.
Download or read book Solar Module Packaging written by Michelle Poliskie and published by CRC Press. This book was released on 2016-04-19 with total page 281 pages. Available in PDF, EPUB and Kindle. Book excerpt: Exploring current and future opportunities in PV polymeric packaging, this work offers an insider's perspective on the manufacturing processes and needs of the solar industry and reveals opportunities for future material development and processing. Suitable for nonspecialists in polymer science, it provides a basic understanding of polymeric concepts, fundamental properties, and processing techniques commonly used in solar module packaging. The book also presents guidelines for using polymers in commercial PV modules as well as the tests required to establish confidence in the selection process.
Download or read book Progress in High Efficient Solution Process Organic Photovoltaic Devices written by Yang Yang and published by Springer. This book was released on 2015-02-17 with total page 421 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents an important technique to process organic photovoltaic devices. The basics, materials aspects and manufacturing of photovoltaic devices with solution processing are explained. Solution processable organic solar cells - polymer or solution processable small molecules - have the potential to significantly reduce the costs for solar electricity and energy payback time due to the low material costs for the cells, low cost and fast fabrication processes (ambient, roll-to-roll), high material utilization etc. In addition, organic photovoltaics (OPV) also provides attractive properties like flexibility, colorful displays and transparency which could open new market opportunities. The material and device innovations lead to improved efficiency by 8% for organic photovoltaic solar cells, compared to 4% in 2005. Both academic and industry research have significant interest in the development of this technology. This book gives an overview of the booming technology, focusing on the solution process for organic solar cells and provides a state-of-the-art report of the latest developments. World class experts cover fundamental, materials, devices and manufacturing technology of OPV technology.
Download or read book Device Interface Process and Electrode Engineering Towards Low Cost and High Efficiency Polymer Solar Cells in Inverted Structure written by Jingyu Zou and published by . This book was released on 2013 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: As a promising technology for economically viable alternative energy source, polymer solar cells (PSCs) have attracted substantial interests and made significant progress in the past few years, due the advantages of being potentially easily solution processed into large areas, flexible, light weight, and have the versatility of material design. In this dissertation, an integrated approach is taken to improve the overall performance of polymer solar cells by the development of new polymer materials, device architectures, interface engineering of the contacts between layers, and new transparent electrodes. First, several new classes of polymers are explored as potential light harvesting materials for solar cells. Processing has been optimized and efficiency as high as 6.24% has been demonstrated. Then, with the development of inverted device structure, which has better air stability by utilizing more air stable, high work function metals, newly developed high efficiency polymers have been integrated into inverted structure device with integrated engineering approach. A comprehensive characterization and optical modeling based on conventional and inverted devices have been performed to understand the effect of device geometry on photovoltaic performance based on a newly developed high performance polymer poly(indacenodithiophene-co-phananthrene-quinoxaline) (PIDT-PhanQ). By modifying anode with a bilayer combining graphene oxide (GO) and poly(3,4-ethylenedioxylenethiophene):poly(styrenesulfonic acid) (PEDOT:PSS) as hole transporter/electron blocker, it further improved device performance of inverted structured to 6.38%. A novel processing method of sequentially bilayer deposition for active layer has been conducted based on a low band-gap polymer poly[2, 6-(4, 4-bis-(2-ethylhexyl)-4H-cyclopenta [2,1-b;3,4-bʹ] dithiophene)-alt-4,7-(2, 1, 3- fluorobenzothiadiazole)] (PCPDT-FBT). Inverted structure devices processed from bilayer deposition shows even higher performance than bulk-heterojunction. Polymer and fullerene distribute uniformly throughout the layer in vertical direction. Better electron mobility and better crystallinity in inverted bilayer film bas been observed, which can contribute to the higher IQE in inverted bilayer device. Metal grid/conducting polymer hybrid transparent electrode has been proved can be an alternative to ITO in inverted structure with similar device performance. Further, a novel protocol to fabricate highly transparent ultra thin silver films as transparent electrode on both glass and plastic substrates also has been demonstrated, based on ZnO/Ag/ZnO tri-layer structure and self-assembled monolayer interfacial modification. Sophisticated interfacial engineering method is applied at necessary interfaces to functioning the ultra thin silver film as a platform for polymer solar cells, and superior device performance that even exceeds using ITO has been achieved.
Download or read book Achieving High Performance Polymer Tandem Solar Cells Via Novel Materials Design written by Letian Dou and published by . This book was released on 2014 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic photovoltaic (OPV) devices show great promise in low-cost, flexible, lightweight, and large-area energy-generation applications. Nonetheless, most of the materials designed today always suffer from the inherent disadvantage of not having a broad absorption range, and relatively low mobility, which limit the utilization of the full solar spectrum. Tandem solar cells provide an effective way to harvest a broader spectrum of solar radiation by combining two or more solar cells with different absorption bands. However, for polymer solar cells, the performance of tandem devices lags behind single-layer solar cells mainly due to the lack of suitable low-bandgap polymers (near-IR absorbing polymers). In this dissertation, in order to achieve high performance, we focus on design and synthesis of novel low bandgap polymers specifically for tandem solar cells. In Chapter 3, I demonstrate highly efficient single junction and tandem polymer solar cells featuring a spectrally matched low-bandgap conjugated polymer (PBDTT-DPP: bandgap, ~1.44 eV). The polymer has a backbone based on alternating benzodithiophene and diketopyrrolopyrrole units. A single-layer device based on the polymer provides a power conversion efficiency of ~6%. When the polymer is applied to tandem solar cells, a power conversion efficiency of 8.62% is achieved, which was the highest certified efficiency for a polymer solar cell. To further improve this material system, in Chapter 4, I show that the reduction of the bandgap and the enhancement of the charge transport properties of the low bandgap polymer PBDTT-DPP can be accomplished simultaneously by substituting the sulfur atoms on the DPP unit with selenium atoms. The newly designed polymer PBDTT-SeDPP (Eg = 1.38 eV) shows excellent photovoltaic performance in single junction devices with PCEs over 7% and photo-response up to 900 nm. Tandem polymer solar cells based on PBDTT-SeDPP are also demonstrated with a 9.5% PCE, which are more than 10% enhancement over those based on PBDTT-DPP. Finally, in Chapter 5, I demonstrate a new polymer system based on alternating dithienopyran and benzothiadiazole units with a bandgap of 1.38 eV, high mobility, deep highest occupied molecular orbital. As a result, a single-junction device shows high external quantum efficiency of>60% and spectral response that extends to 900 nm, with a power conversion efficiency of 7.9%. The polymer enables a solution processed tandem solar cell with certified 10.6% power conversion efficiency under standard reporting conditions, which is the first certified polymer solar cell efficiency over 10%.
Download or read book Employing Polymer Ionic Liquid and Low Temperature Oxygen Plasma Process for Planar Perovskite Solar Cells written by 王語彤 and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sol gel ALD Low Temperature Process written by Fatma Trabelsi and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solar energy remains one of the most common renewable energy sources. Using photovoltaic cells, the energy of sunlight can be converted into electricity. Unfortunately, one of the main drawbacks of Si solar cells is their limited efficiency absorption of long wavelength sunlight. To address this issue, special attention is given to the upconversion luminescence process in which the sequential absorption of two or more photons leads to the emission of light at shorter wavelength (Visible) than the excitation wavelength (Near Infra Red) that can be reabsorbed by the cell. In this context, the work of this PhD thesis aims to develop coated upconversion nanopowder based thin films to extend the spectral sensitivity of solar cells to the NIR (Near Infra Red) spectrum.The idea is to investigate the efficiency of a low temperature procedure to get an efficient upconversion emission that can be used to improve the performance of Si solar cells. The structural, morphological and composition properties after every step of the proposed approach are examined in details. For the nanopowder based thin film, TiO2 is chosen as host material and Er3+/Yb3+, embedded as activator/sensitizer, to play the role of spectrum modifier. This nanopowder based thin film is formed through an optimization of the dispersion (pH, ultrasonication) and deposition (spin coating parameters) steps of the elaborated upconversion nanopowder. The Atomic Layer Deposition (ALD) layer of Al2O3 material followed by thermal treatment is used as an important tool for Si passivation through defects reducing. In addition, its potential application as a barrier from the surrounding environment helps to avoid the supressing of luminescence. The influence of thickness layer and thermal treatment on upconversion luminescence and structural properties of the nanopowder-based films are studied. It is concluded that ALD reinforced nanopowder thin films retained the original functionality of the nanopowder related to upconversion phenomenon. Interestingly, by tuning the thickness of the coating layer, enhancement by 98% of the green upconversion emission can be obtained, it is proved that Al2O3 acts as a barrier to decrease the quenching of luminescence and promote the light absorption. Furthermore, the effect of ALD coating and thermal treatment on adhesion and hardness of the coated nanopowder based films is investigated. The combination of the common steps used for enhancing electrical properties with good luminescence and mechanical properties makes these films more attractive.
Download or read book Cohesion and Decohesion Kinetics of Polymer Solar Cells written by Christopher Bruner and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymer organic solar cells (OSCs) possess many desirable properties include low temperature solution processibility of photoactive materials and the utilization of flexible substrates for conformal OSC design. However, challenges remain that may inhibit their adoption and implementation. Among these are thermochemical stability, optimized power conversion efficiency, and mechanical reliability. Indeed, for organic solar cells to be used on flexible substrates, mechanical reliability of the individual layers and interfaces is pertinent. In this dissertation, quantitative micromechanical testing techniques were employed to help characterize the mechanical reliability of the layers and interfaces for polymer OSCs. From testing, it was determined that the polymer:fullerene photoactive layer consistently failed cohesively. The cohesive strength of most photoactive layers generally ranged from 0.5 to 2.0 Joules per square meter. However, by using thermal annealing, manipulating the photoactive layer structure, and selecting polymer molecular weight, cohesion values as high as 17 Joules per square meter could be achieved. Indeed, polymer molecular weight affected cohesion the most due to significant plasticity within the photoactive layer. Conversely, improved cohesion did not always result in improved device electronic performance. By optimizing cohesion and efficiency, we are able to come closer to design guidelines for mechanically robust and efficient solar cells. Finally, because OSCs must operate in the environment at temperatures as high as 65 C, we analyzed OSCs under dry, inert environmental conditions and showed how temperature affects the decohesion kinetics within the device. It was demonstrated that the decohesion rate generally accelerated with increasing test temperature. We were able to develop a viscoelastic kinetic model that was able to describe and predict decohesion for these devices. This collective work and modeling will provide greater insight into the practical limitations of OSC design and will aid in future development of OSCs with greater mechanical reliability and in-service lifetimes.
Download or read book Polymer and Hybrid Photovoltaics written by Chen and published by . This book was released on with total page 800 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
