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Identifying Electronic Properties Relevant To Improving The Performance And Stability Of Amorphous Silicon Based Mid Gap And Low Gap Cells
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Book Synopsis Identifying Electronic Properties Relevant to Improving the Performance and Stability of Amorphous Silicon Based Mid-gap and Low-gap Cells by : J. David Cohen
Download or read book Identifying Electronic Properties Relevant to Improving the Performance and Stability of Amorphous Silicon Based Mid-gap and Low-gap Cells written by J. David Cohen and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Identifying Electronic Properties Relevant to Improving the Performance and Stability of Amorphous Silicon-based Mid-gap and Low-gap Cells by : J. David Cohen
Download or read book Identifying Electronic Properties Relevant to Improving the Performance and Stability of Amorphous Silicon-based Mid-gap and Low-gap Cells written by J. David Cohen and published by . This book was released on 2000 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Identifying Electronic Properties Relevant to Improving the Performance and Stability of Amorphous Silicon Based Mid-Gap and Low-Gap Cells by :
Download or read book Identifying Electronic Properties Relevant to Improving the Performance and Stability of Amorphous Silicon Based Mid-Gap and Low-Gap Cells written by and published by . This book was released on 2002 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes our experimental studies which have been concentrated in roughly five areas. Specifically: (1) We have examined a?Si:H grown very close to the microcrystalline phase boundary, so-called''edge material, '' to help understand why such material is more stable with respect to light-induced degradation; (2) We have also studied the electronic properties, and degradation characteristics of mixed phase material that is mostly a?Si:H, but which contains a significant microcrystalline component; (3) We have examined the electronic properties of high deposition rate material. These studies have included both moderately high deposition rate material (up to 6/s) produced by the PECVD growth method, and extremely high deposition rate material (up to 130/s) produced by the HWCVD growth method. (4) We have examined series of a-Si, Ge:H alloys from several sources. In one extensive series of studies we examined low Ge fraction alloys in an attempt to learn more about the fundamentals of degradation in general. In a couple other studies we evaluated the properties of a-Si, Ge:H alloys produced by methods we had not previously examined. (5) Finally, for three different types of samples we compared basic material properties with companion cell performance data. This was carried out in each case on series of samples for which one or more specific deposition parameters were varied systematically.
Book Synopsis Identifying Electronic Properties Relevant to Improving the Performance and Stability of Amorphous Silicon-based Mid-gap and Low-gap Cells by :
Download or read book Identifying Electronic Properties Relevant to Improving the Performance and Stability of Amorphous Silicon-based Mid-gap and Low-gap Cells written by and published by . This book was released on 2000 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: An overriding theme of the work described in this report has been the effect of partial crystallinity, or the approach to partial crystallinity, on the electronic properties of a-Si:H. This includes, of course, how degradation or the relative stability of these films is affected by the approach to, or onset of, microcrystallinity. The authors first discussed the results on a set of samples produced by dc reactive magnetron sputtering, obtained in collaboration with John Abelson's group at the University of Illinois, for which they demonstrated the existence of a small, but significant, microcrystalline component. For these films, the degradation kinetics was found to be quite unusual; however, it could be well accounted for by a model that postulated two phases of degrading material. One was a-Si:H host material of good quality and the other was a more defective component associated with boundary regions near the microcrystallites. The sub-band-gap photocapacitance measurements on these films also indicated the existence of a distinct feature (a ''shoulder'' with a threshold near 1.1 eV) that signaled the presence of the microcrystalline phase. The second set of samples investigated were produced by Uni-Solar, deposited under conditions of high hydrogen dilution, very close to but just below the microcrystalline phase boundary. Here they found that the defect density following light-induced degradation decreased as the film thickness increased. Corroborating their findings with X-ray diffraction results obtained by Don Williamson on sets of similar films, the authors concluded that the films were becoming more ordered and less defective just prior to the onset of a detectable microcrystalline component. Furthermore, they found that at almost exactly the conditions that Williamson found XRD evidence for the onset of microcrystallinity, they found the appearance of the distinctive ''shoulder'' in the sub-band-gap photocapacitance spectra. Third, they investigated two sets of samples where the deposition rate had been varied to include samples grown at moderate to high rates. In one set of samples, produced at ETL, samples deposited under H2 dilution were found to exhibit extremely low deep defect densities and narrow Urbach tails, indicating films of exceptional quality. The photocapacitance spectra for these films were found to contain evidence for a small degree of microcrystallinity. In another set of samples, produced at UniSolar, they found evidence for increasing defect densities plus somewhat larger Urbach energies for the films deposited at higher rates. This is consistent with the fact that the photovoltaic device performance is significantly poorer for the higher deposition rate material. Finally, they discussed the general issue of deep defect densities in the a-Si, Ge:H alloys. They again demonstrated how well the deep defect densities in such samples from several sources could be fit using the spontaneous bond-breaking model of Martin Stutzmann. This implies that such state-of-the-art alloy films have been optimized in a quantifiable sense. They also found that the increase in deep defect density with small amounts of P and B dopants could also be reproduced reasonably well by modifying the spontaneous bond-breaking model to include the extra energy terms associated with charged defects.
Book Synopsis Identifying Electronic Properties Relevant to Improving Stability in A-Si:H-based Cells and Overall Performance in A-Si, Ge:H-based Cells by : J. David Cohen
Download or read book Identifying Electronic Properties Relevant to Improving Stability in A-Si:H-based Cells and Overall Performance in A-Si, Ge:H-based Cells written by J. David Cohen and published by . This book was released on 1998 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Silicon Heterojunction Solar Cells by : W.R. Fahrner
Download or read book Silicon Heterojunction Solar Cells written by W.R. Fahrner and published by Trans Tech Publications Ltd. This book was released on 2006-08-15 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: The world of today must face up to two contradictory energy problems: on the one hand, there is the sharply growing consumer demand in countries such as China and India. On the other hand, natural resources are dwindling. Moreover, many of those countries which still possess substantial gas and oil supplies are politically unstable. As a result, renewable natural energy sources have received great attention. Among these, solar-cell technology is one of the most promising candidates. However, there still remains the problem of the manufacturing costs of such cells. Many attempts have been made to reduce the production costs of conventional solar cells (manufactured from monocrystalline silicon using diffusion methods) by instead using cheaper grades of silicon, and simpler pn-junction fabrication. That is the hero of this book; the heterojunction solar cell.
Book Synopsis Amorphous and Polycrystalline Thin Film Silicon Science and Technology - 2009: Volume 1153 by : Andrew Flewitt
Download or read book Amorphous and Polycrystalline Thin Film Silicon Science and Technology - 2009: Volume 1153 written by Andrew Flewitt and published by . This book was released on 2009-12-22 with total page 514 pages. Available in PDF, EPUB and Kindle. Book excerpt: The MRS Symposium Proceeding series is an internationally recognised reference suitable for researchers and practitioners.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1990 with total page 834 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Solar Energy written by Christoph Richter and published by Springer. This book was released on 2012-11-29 with total page 744 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gathering some 30 entries from the Encyclopedia of Sustainability Science and Technology, this book presents fundamental principles and technologies for sustainably harnessing solar energy. Covers photovoltaics, solar thermal energy, solar radiation and more.
Book Synopsis Electronic Structure of ?-Conjugated Materials and Their Effect on Organic Photovoltaics by : Chuanfei Wang
Download or read book Electronic Structure of ?-Conjugated Materials and Their Effect on Organic Photovoltaics written by Chuanfei Wang and published by Linköping University Electronic Press. This book was released on 2017-11-15 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: The great tunability of structure and electronic properties of ?-conjugated organic molecules/polymers combined with other advantages such as light weight and flexibility etc., have made organic-based electronics the focus of an exciting still-growing field of physics and chemistry for more than half a century. The application of organic electronics has led to the appearance of wide range of organic electronic devices mainly including organic light emitting diodes (OLED), organic field effect transistors (OFET) and organic solar cells (OSC). The application of the organic electronic devices mainly is limited by two dominant parameters, i.e., their performance and stability. Up to date, OLED has been successfully commercialized in the market while the OSC are still on the way to commercialization hindered by low efficiency and inferior stability. Understanding the energy levels of organic materials and energy level alignment of the devices is crucial to control the efficiency and stability of the OSC. In this thesis, energy levels measured by different methods are studied to explore their relationship with device properties, and the strategies on how to design efficient and stable OSC based on energy level diagrams are provided. Cyclic Voltammetry (CV) is a traditional and widely used method to probe the energy levels of organic materials, although there is little consensus on how to relate the oxidation/reduction potential ((Eox/Ered) to the vacuum level. Ultraviolet Photoelectron Spectroscopy (UPS) can be used to directly detect vertical ionization potential (IP) of organic materials. In this thesis, a linear relationship of IP and Eox was found, with a slope equal to unity. The relationship provides for easy conversion of values obtained by the two techniques, enabling complementarily use in designing and fabricating efficient and stable OSC. A popular rule of thumb is that the offset between the LUMO levels of donor and acceptor should be 0.3 eV, according to which a binary solar cell with the minimum voltage losses around 0.49 V was designed here. Introduction of the ternary blend as active layer is an efficient way to improve both efficiency and stability of the OSC. Based on our studied energy-level diagram within the integer charge transfer (ICT) model, we designed ternary solar cells with enhanced open circuit voltage for the first time and improved thermal stability compared to reference binary ones. The ternary solar cell with minimum voltage losses was developed by combining two donor materials with same ionization potential and positive ICT energy while featuring complementary optical absorption. Furthermore, the fullerene acceptor was chosen so that the energy of the positive ICT state of the two donor polymers is equal to the energy of negative ICT state of the fullerene, which can enhance dissociation of all polymer donor and fullerene acceptor excitons and suppress bimolecular and trap-assistant recombination. Rapid development of non-fullerene acceptors in the last two years affords more recipes of designing both efficient and stabile OSC. We show in this thesis how non-fullerene acceptors successfully can be used to design ternary solar cells with both enhanced efficiency and thermal stability. Besides improving the efficiency of the devices, understanding of the stability and degradation mechanism is another key issue. The degradation of conjugated molecules/polymers often follow many complicated pathways and at the same time many factors for degradation are coupled with each other. Therefore, the degradation of non-fullerene acceptors was investigated in darkness by photoelectron spectroscopy in this thesis with the in-situ method of controlling exposure of O2 and water vapor separately.
Book Synopsis Technology and Applications of Amorphous Silicon by : Robert A. Street
Download or read book Technology and Applications of Amorphous Silicon written by Robert A. Street and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 429 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gives the first systematic and complete survey of technology and application of amorphous silicon, a material with a huge potential in electronic applications. The book features contributions by world-wide leading researchers in this field.
Book Synopsis Stability of Amorphous Silicon Alloy Materials and Devices by : B. L. Stafford
Download or read book Stability of Amorphous Silicon Alloy Materials and Devices written by B. L. Stafford and published by American Institute of Physics. This book was released on 1987 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Photoelectrochemical Water Splitting by : H.- J. Lewerenz
Download or read book Photoelectrochemical Water Splitting written by H.- J. Lewerenz and published by Royal Society of Chemistry. This book was released on 2013 with total page 497 pages. Available in PDF, EPUB and Kindle. Book excerpt: There has been a resurgence of interest in light-induced water splitting as the search for storable carbon neutral energy becomes more urgent. Although the history of the basic idea dates back more than four decades, efficient, economical and stable integrated devices have yet to be realized. In the continuing quest for such devices, the field of photoelectrochemistry is entering a new phase where the extraordinary interdisciplinary of the research and development efforts are opening new avenues. This aspect of current research effort is reflected in the chapters of this book, which encompass present thinking in the various disciplines such as materials science, photo-electrochemistry and interfaces that can contribute to realization of viable solar fuel generators. This book presents a blend of the background science and recent advances in the field of photoelectrochemical water splitting, and includes aspects that point towards medium to long term future realization. The content of the book goes beyond the more traditional approaches to the subject by including topics such as novel excitation energy processes that have only been realized so far in advanced photonics. The comprehensive overview of current activities and development horizons provided by the impressive collection of internationally renowned authors therefore represents a unique reflection of current thinking regarding water splitting by light.
Book Synopsis Electrical & Electronics Abstracts by :
Download or read book Electrical & Electronics Abstracts written by and published by . This book was released on 1997 with total page 2240 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Electronic Properties of Semiconductor Superlattices, Amorphous Semiconductors, and Metal-semiconductor Interfaces by : Lin Hung Yang
Download or read book Electronic Properties of Semiconductor Superlattices, Amorphous Semiconductors, and Metal-semiconductor Interfaces written by Lin Hung Yang and published by . This book was released on 1988 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Solar Energy Update written by and published by . This book was released on 1981 with total page 698 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Properties of Amorphous Silicon by :
Download or read book Properties of Amorphous Silicon written by and published by . This book was released on 1985 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt:
