Photon Management in Hydrogenated Amorphous Silicon Solar Cells Using Periodic Nanostructures - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Photon Management in Hydrogenated Amorphous Silicon Solar Cells Using Periodic Nanostructures write by Ching-Mei Hsu. This book was released on 2011. Photon Management in Hydrogenated Amorphous Silicon Solar Cells Using Periodic Nanostructures available in PDF, EPUB and Kindle. Solar technology is a leading candidate for clean energy production. Silicon is an excellent material for photovoltaic (PV) applications due to its low toxicity, abundance, long term stability, and well developed processing technologies. Crystalline Si solar cells currently dominate the photovoltaic market despite requiring more material and more energy-intensive manufacturing processes than their thin-film counterparts. Thin-film silicon, e.g. amorphous silicon (a-Si:H), provides the advantage of decreasing material costs over crystalline silicon. Because the material is amorphous, there are many defects, which results in a small minority carrier diffusion length. Thus, a thinner absorber is required. However, thinner absorber layers do not absorb light effectively, resulting in poor cell performance. If the active material could be made to absorb all of the light in a film with a thickness approximately equal to the minority carrier diffusion length, the open-circuit voltage (Voc), short-circuit current (Jsc), and fill factor (FF) of the device would be greater than those of a thicker cell. My research is comprised of three parts: (1) developing a nanostructure fabrication process, (2) designing device geometries for alternative light trapping strategies in both substrate and superstrate configurations, and (3) investigating the effects of nanostructures' morphologies on the optical and electrical properties of devices. In contrast to the use of randomized surface texturing to improve the coupling of light into the active material, we employed periodic nanostructures to couple incident light into guided modes that propagate in the plane of the absorber. This approach can significantly increase the optical path length inside a thin absorber layer. To achieve this goal, I first developed a nanostructure fabrication process by combining self-assembly and reactive ion etching. We then employ these as-made nanostructures in a-Si:H solar cells. The periodic-nanostructure devices show an enhanced absorption and photocurrent generation in comparison with planar cells. We used FTDT studies to confirm that the increased photocurrent was indeed caused by enhanced absorption. We also systematically studied the effects of morphological parameters on light-trapping efficiency and electrical characteristics of the device. With my optical and electrical findings, we have achieved efficiencies up to 9.7% for devices with substrate configurations and 11.2 % for devices with superstrate configurations.
Amorphous Silicon-Carbon Nanostructure Photovoltaic Devices
Amorphous Silicon-Carbon Nanostructure Photovoltaic Devices - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Amorphous Silicon-Carbon Nanostructure Photovoltaic Devices write by Maria Christine Schriver. This book was released on 2012. Amorphous Silicon-Carbon Nanostructure Photovoltaic Devices available in PDF, EPUB and Kindle. A novel solar cell architecture made completely from the earth abundant elements silicon and carbon has been developed. Hydrogenated amorphous silicon (aSi:H), rather than crystalline silicon, is used as the active material due to its high absorption through a direct band gap of 1.7eV, well matched to the solar spectrum to ensure the possibility of improved cells in this architecture with higher efficiencies. The cells employ a Schottky barrier design wherein the amorphous silicon absorber layer generates electron-hole pairs from incoming photons and holes are preferentially extracted through a metallic material consisting of a carbon nanostructure. Both graphene and buckypaper were used as the metallic component of the Schottky junction to effectively convert incoming light to electricity. Subsequent work focused on graphene-based cells because graphene offers better transparency and conductance compared to buckypaper, making it promising as a top conductor in a solar cell. Reactions of the graphene-aSi:H interface were investigated and strategies developed to minimize reactions that lead to performance degradation. Finally, photon management strategies were executed to significantly enhance the performance of the cells using silver nanoparticles to increase the absorbance of light and extraction of charges in a thin aSi:H film. Solar cells optimized with these improvements show performance enhancements of 1-2 orders of magnitude compared to initially published cells in this architecture. In addition to yielding strategies for improved protection and performance of the solar cells presented in this thesis, investigations presented here into reactions at the graphene-silicon interface should inform further research into applications of graphene.
Photon Management in Solar Cells
Photon Management in Solar Cells - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Photon Management in Solar Cells write by Ralf B. Wehrspohn. This book was released on 2015-06-08. Photon Management in Solar Cells available in PDF, EPUB and Kindle. 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.
Physics and Technology of Amorphous-Crystalline Heterostructure Silicon Solar Cells
Physics and Technology of Amorphous-Crystalline Heterostructure Silicon Solar Cells - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Physics and Technology of Amorphous-Crystalline Heterostructure Silicon Solar Cells write by Wilfried G. J. H. M. van Sark. This book was released on 2011-10-22. Physics and Technology of Amorphous-Crystalline Heterostructure Silicon Solar Cells available in PDF, EPUB and Kindle. Today’s solar cell multi-GW market is dominated by crystalline silicon (c-Si) wafer technology, however new cell concepts are entering the market. One very promising solar cell design to answer these needs is the silicon hetero-junction solar cell, of which the emitter and back surface field are basically produced by a low temperature growth of ultra-thin layers of amorphous silicon. In this design, amorphous silicon (a-Si:H) constitutes both „emitter“ and „base-contact/back surface field“ on both sides of a thin crystalline silicon wafer-base (c-Si) where the electrons and holes are photogenerated; at the same time, a-Si:H passivates the c-Si surface. Recently, cell efficiencies above 23% have been demonstrated for such solar cells. In this book, the editors present an overview of the state-of-the-art in physics and technology of amorphous-crystalline heterostructure silicon solar cells. The heterojunction concept is introduced, processes and resulting properties of the materials used in the cell and their heterointerfaces are discussed and characterization techniques and simulation tools are presented.
Amorphous and Microcrystalline Silicon Applied in Very Thin Tandem Solar Cells
Amorphous and Microcrystalline Silicon Applied in Very Thin Tandem Solar Cells - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Amorphous and Microcrystalline Silicon Applied in Very Thin Tandem Solar Cells write by Sandra Schicho. This book was released on 2011. Amorphous and Microcrystalline Silicon Applied in Very Thin Tandem Solar Cells available in PDF, EPUB and Kindle.
