Download or read book Ultrathin Crystalline Silicon Solar Cells Incorporating Advanced Light trapping Structures written by Matthew S. Branham and published by . This book was released on 2015 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solar photovoltaics, which convert the energy potential of photons from the sun directly into electrical power, hold immense promise as a cornerstone of a clean energy future. Yet their cost remains greater than that of conventional energy sources in most markets and a barrier to large-scale adoption. Crystalline silicon modules, with a 90% share of the worldwide photovoltaic market, have witnessed a precipitous drop in price over the last decade. But going forward, further evolutionary cost reduction will be difficult given the significant cost of the silicon wafer alone - roughly 35% of the module. Dramatically reducing the thickness of silicon used to make a solar cell from the current 350 [mu]m could rewrite the economics of photovoltaics. For thin-film crystalline silicon solar cells to deliver the anticipated cost benefits of reduced material requirements, it is essential that they also yield power conversion efficiencies comparable to commercial solar cells. A significant hurdle to realizing elevated efficiency in crystalline silicon films thinner than 20 [mu]m is the loss of current resulting from reduced photon absorption. A range of light management structures have been proposed in the literature to address this issue and many have been demonstrated to provide high absorption across the spectral range relevant to crystalline silicon, but their promise has yet to be realized in an active photovoltaic device. The focus of this thesis is the development of an experimental platform and fabrication process to evaluate the effectiveness of theoretically-designed light-trapping structures in functional photovoltaic devices. The experimental effort yielded 10-pm-thick crystalline silicon solar cells with a peak short-circuit current of 34.5 mA cm-2 and power conversion efficiency of 15.7%. The record performance for a crystalline silicon photovoltaic of such thinness is enabled by an advanced light-trapping design incorporating a 2D photonic crystal and a rear dielectric/reflector stack. A parallel line of questioning addressed in this thesis is whether periodic wavelength-scale optical structures are superior to periodic or random structures with geometric-optics-scale features. Through the synthesis of experimental and theoretical evidence, the case is constructed that wavelength-scale light-trapping structures are in fact comparable to conventional random pyramid surface structures for broad-spectrum absorption in silicon solar cells as thin as 5 [mu]m. These results have important implications for the design of cost-effective and manufacturable light-trapping structures for ultrathin crystalline silicon solar cells.
Download or read book High efficiency Ultrathin Crystalline Silicon Solar Cells written by Muyu Xue and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The climate change associated with burning fossil fuels as dominant energy resource has been a significant concern. Solar photovoltaics (PV) is the dominant type of renewable and eco-friendly energy resource to alleviate this problem. Crystalline silicon (c-Si) PV has been the dominant type of solar cell with more than 90% of the global PV market at the end of 2017, because of its low-cost, good stability and well-developed processing technology. To continue reducing the price of solar modules, ultrathin c-Si solar cells have been investigated: they are a feasible pathway to continue "price scaling" by effectively reducing the c-Si material consumption. However, the performance of ultrathin c-Si cells is constrained by two physical limitations: poor light absorption and contact recombination. To achieve the optimal efficiency from ultrathin c-Si cells, the cells must be designed to overcome these limitations. This dissertation provides comprehensive experimental strategies to overcome these two performance limitations of ultrathin c-Si solar cells. The main part of this dissertation concludes with the characterization of the "free-standing", ultrathin c-Si cell integrated with carrier-selective contacts and light trapping structures. These cells show very consistent performance before and after being released from the substrate. These findings show the capability of ultrathin c-Si technology to not only reduce the material cost, but also maintain high efficiency.
Download or read book Design and Fabrication of Nanostructures for Light trapping in Ultra thin Solar Cells written by Inès Massiot and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reducing the absorber thickness is an attractive solution to decrease the production cost of solar cells. Furthermore, it allows to reduce the amount of material needed and improve the current collection in the cell. This thesis has been focused on the design of nanostructures to enhance light absorption in very small semiconductor volumes in order to achieve efficient ultra-thin solar cells. First, we have proposed an original light-trapping concept for ultra-thin amorphous silicon (a-Si:H) solar cells. A one-dimensional metallic grating is patterned on the front surface of the cell deposited on a metallic mirror. Broadband multi-resonant absorption has been demonstrated for both light polarizations. The metallic grating is also used as an alternative transparent electrode in order to reduce optical losses in the front contact. A detailed analysis of the multi-resonant absorption mechanism has been carried out through numerical calculations. The fabrication and optical characterization of ultra-thin a-Si:H solar cells with metallic gratings have validated the multi-resonant approach.Second, we have proposed a design with a two-dimensional metallic grid as a resonant front contact for very thin (25 nm) gallium arsenide (GaAs) layers. We have shown through the design and fabrication of a proof-of-concept structure the potential of metallic nanogrids to confine efficiently light absorption with an ultra-thin GaAs layer.Finally, advanced light-trapping structures could also allow a thickness reduction of crystalline silicon wafers of a factor 20 to 100 with respect to state-of-the-art cells. We have developed a process to transfer micron-thick epitaxial crystalline silicon (c-Si) layers onto a low-cost host substrate. Inverted nanopyramids have also been fabricated in crystalline silicon in order to achieve a broadband anti-reflection effect. It opens promising perspectives towards the realization of double-sided nanopatterned ultra-thin c-Si cells.
Download or read book Ultrathin Mono crystalline Silicon Photovoltaic Cells with Mechanically Flexible and Stretchable Designs and Light trapping Structures written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Light Trapping in Crystalline Silicon Solar Cells written by Ulf Blieske and published by . This book was released on 1989 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Light Trapping in High efficiency Crystalline Silicon Solar Cells written by Johannes Eisenlohr and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Light Trapping in Thin Crystalline Silicon Solar Cells written by James A. Rand and published by . This book was released on 1990 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thin Film Crystalline Silicon Solar Cells written by Rolf Brendel and published by John Wiley & Sons. This book was released on 2011-02-15 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: This introduction to the physics of silicon solar cells focuses on thin cells, while reviewing and discussing the current status of the important technology. An analysis of the spectral quantum efficiency of thin solar cells is given as well as a full set of analytical models. This is the first comprehensive treatment of light trapping techniques for the enhancement of the optical absorption in thin silicon films.
Download or read book High Efficiency Silicon Solar Cells written by Martin A. Green and published by Trans Tech Publications Ltd. This book was released on 1987-01-01 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: The early chapters comprehensively review the optical and transport properties of silicon. Light trapping is described in detail. Limits on the efficiency of silicon cells are discussed as well as material requirements necessary to approach these limits. The status of current approaches to passifying surfaces, contacts and bulk regions is reviewed. The final section of the book describes the most practical approaches to the fabrication of high-efficiency cells capable of meeting the efficiency targets for both concentrated and non-concentrated sunlight, including a discussion of design and processing approaches for non-crystalline silicon.
Download or read book Harvesting Photon Energy written by Wei-Chun Hsu and published by . This book was released on 2016 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: Photons from the sun and terrestrial sources have great potential to satisfy the energy demand of humans. This thesis studies two types of energy conversion technologies, photovoltaic solar cells based on crystalline silicon thin films and thermal-radiative cells using terrestrial heat sources, focusing on managing photons but also concurrently considering electron transport and entropy generation. Photovoltaic technology has been widely adopted to convert solar energy into electricity. Crystalline silicon material occupies ~90% of the photovoltaic market. However, the silicon material in a photovoltaic module with ~180-pm-thick silicon material contributes more than 30% of the overall cost, giving rise to an obstacle to compete with fossil fuel energy. One promising solution to break this barrier is the technology of thin-film crystalline silicon solar cells if the weak absorption of silicon can be overcome. To maintain its high energy conversion efficiency, nanostructure is designed considering both light trapping and electron collection. This design guided the fabrication of 10-pm-thick crystalline silicon photovoltaic cells with efficiencies as high as 15.7%. To reach efficiency >20% in industry, multiple strategies have been investigated to further improve the performance including the least-common-multiple rule for the double gratings structure, external optical cavity, high quality silicon in bulk material and interfaces, and optimal contact spacing and doping. For the energy conversion of terrestrial heat source, a direct bandgap solar cell can work in the reverse bias mode to convert energy into electricity companied by emission of photons as entropy carriers. Photon spectral entropy and fluxes are used to develop strategies for improving the heat to electricity conversion efficiency. Near-field radiative transfer, especially using phonon polariton material to couple out emitted photons from electron-hole recombination, is proposed to enhance energy conversion efficiency as well as the power density. We predict that the InSb thermoradiative cell can achieve the efficiency and power density up to 20.4 % and 327 Wm-2, respectively, between a hot source at 500K and a cold sink at 300K, if the sub-bandgap and non-radiative losses could be avoided.
Download or read book Photon Management in Solar Cells written by Ralf B. Wehrspohn and published by John Wiley & Sons. This book was released on 2015-06-08 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by renowned experts in the field of photon management in solar cells, this one-stop reference gives an introduction to the physics of light management in solar cells, and discusses the different concepts and methods of applying photon management. The authors cover the physics, principles, concepts, technologies, and methods used, explaining how to increase the efficiency of solar cells by splitting or modifying the solar spectrum before they absorb the sunlight. In so doing, they present novel concepts and materials allowing for the cheaper, more flexible manufacture of solar cells and systems. For educational purposes, the authors have split the reasons for photon management into spatial and spectral light management. Bridging the gap between the photonics and the photovoltaics communities, this is an invaluable reference for materials scientists, physicists in industry, experimental physicists, lecturers in physics, Ph.D. students in physics and material sciences, engineers in power technology, applied and surface physicists.
Download or read book Advanced Methods for Light Trapping in Optically Thin Silicon Solar Cells written by James Richard Nagel and published by . This book was released on 2011 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thin film Silicon Solar Cells written by Xing Sheng (Ph. D.) and published by . This book was released on 2012 with total page 159 pages. Available in PDF, EPUB and Kindle. Book excerpt: The photovoltaic technology has been attracting widespread attention because of its effective energy harvest by directly converting solar energy into electricity. Thin-film silicon solar cells are believed to be a promising candidate for further scaled-up production and cost reduction while maintaining the advantages of bulk silicon. The efficiency of thin-film Si solar cells critically depends on optical absorption in the silicon layer since silicon has low absorption coefficient in the red and near-infrared (IR) wavelength ranges due to its indirect bandgap nature. This thesis aims at understanding, designing, and fabricating novel photonic structures for efficiency enhancement in thin-film Si solar cells. We have explored a previously reported a photonic crystal (PC) based structure to improve light absorption in thin-film Si solar cells. The PC structure combines a dielectric grating layer and a distributed Bragg reflector (DBR) for effcient light scattering and reflection, increasing light path length in the thin-film cell. We have understood the operation principles for this design by using photonic band theories and electromagnetic wave simulations. we discover that this DBR with gratings exhibit unusual light trapping in a way different from metal reflectors and photonic crystals. The light trapping effects for the DBR with and without reflector are numerically investigated. The self-assembled anodic aluminum oxide (AAO) technique is introduced to non- lithographically fabricate the grating structure. We adjust the AAO structural parameters by using different anodization voltages, times and electrolytes. Two-step anodization is employed to obtain nearly hexagonal AAO pattern. The interpore periods of the fabricated AAO are calculated by fast Fourier transform (FFT) analysis. We have also demonstrated the fabrication of ordered patterns made of other materials like amorphous Si (a-Si) and silver by using the AAO membrane as a deposition mask. Numerical simulations predict that the fabricated AAO pattern exhibits light trapping performance comparable to the perfectly periodic grating layer. We have implemented the light trapping concepts combining the self-assembled AAO layer and the DBR in the backside of crystalline Si wafers. Photoconductivity measurements suggest that the light absorption is improved in the near-IR spectral range near the band edge of Si. Furthermore, different types of thin-film Si solar cells, including a-Si, mi- crocrystalline Si ([mu]-Si) and micromorph Si solar cells, are investigated. For demonstration, the designed structure is integrated into a 1:5 [mu]m thick [mu]c-Si solar cell. We use numerical simulations to obtain the optimal structure parameters for the grating and the DBR, and then we fabricate the optimized structures using the AAO membrane as a template. The prototype devices integrating our proposed backside structure yield a 21% improvement in efficiency. This is further verified by quantum efficiency measurements, which clearly indicate stronger light absorption in the red and near-IR spectral ranges. Lastly, we have explored the fundamental light trapping limits for thin-film Si solar cells in the wave optics regime. We develop a deterministic method to optimize periodic textures for light trapping. Deep and high-index-contrast textures exhibit strong anisotropic scattering that is outside the regime of validity of the Lambertian models commonly used to describe texture-induced absorption enhancement for normal incidence. In the weak ab- sorption regime, our optimized surface texture in two dimensions (2D) enhances absorption by a factor of 2.7[pi]n, considerably larger than the classical [pi]n Lambertian result and exceeding by almost 50% a recent generalization of Lambertian model for periodic structures in finite spectral range. Since the [pi]n Lambertian limit still applies for isotropic incident light, our optimization methodology can be thought of optimizing the angle/enhancement tradeoff for periodic textures. Based on a modified Shockley-Queisser theory, we conclude that it is possible to achieve more than 20% efficiency in a 1:5 [mu]m thick crystalline Si cell if advanced light trapping schemes can be realized.
Download or read book Light Trapping and Reflection Control in a Crystalline Silicon Solar Cell written by Patrick Ross Campbell and published by . This book was released on 1989 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Thin Film Silicon Solar Cells written by Arvind Victor Shah and published by CRC Press. This book was released on 2010-08-19 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt: Photovoltaic technology has now developed to the extent that it is close to fulfilling the vision of a "solar-energy world," as devices based on this technology are becoming efficient, low-cost and durable. This book provides a comprehensive treatment of thin-film silicon, a prevalent PV material, in terms of its semiconductor nature, startin
Download or read book Light Trapping by Micro and Nano hole Texturing of Single crystalline Silicon Solar Cells written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
