159 research outputs found
Atmospheric pressure chemical vapor deposition of aluminum oxide for silicon surface passivation—background and materials science
No full textThe author provides a general background on atmospheric pressure chemical vapor deposition (APCVD) of Al2O3, from its origins to more recent research, focusing on surface passivation applications for solar cells and the composition and structure of the APCVD Al2O3-Si interface. Chapter Contents: • 6.1 Background on atmospheric pressure chemical vapor deposition • 6.2 Composition and structure of the APCVD Al2O3-Si interface • References
Laser Sintered Silver Metallization for Silicon Heterojunction Photovoltaics
No full textThis dataset features process information and measurements data on laser sintered silver metal contacts used for silicon heterojunction photovoltaics. This includes resistivity data, photoluminescence images, and scanning electron microscopy images
Dataset - Incorporation of Spatially-Resolved Current Density Measurements with Photoluminescence for Advanced Parameter Imaging of Solar Cells
No full textThis dataset contains the I-V curves and solar cell parameter images associated with the following publication.Hossain, M. J., Schneller, E. J., Li, M. & Davis, K. O. Incorporation of spatially-resolved current density measurements with photoluminescence for advanced parameter imaging of solar cells. Solar Energy Materials and Solar Cells 199, 136–143 (2019). DOI: 10.1016/j.solmat.2019.04.012</div
Efeitos da cadência de pedalada nas respostas fisiológicas e no tempo de exaustão do exercício realizado a 100 e 105% da potência crítica em ciclistas treinados
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Desportos, Programa de Pós-graduação em Educação Física, Florianópolis, 2011Introdução: A potência crítica (PC) é estabelecida como sendo o limite superior do domínio pesado. Além disso, tem sido demonstrado que a cadência de pedalada influencia nas respostas fisiológicas e no tempo de exaustão (tlim) do exercício realizado nos domínios pesado e severo. Sendo assim, o objetivo deste estudo foi analisar os efeitos de diferentes cadências de pedalada nas respostas fisiológicas e no tlim do exercício realizado na PC e em 105%PC de ciclistas treinados. Metodologia: Participaram deste estudo 13 ciclistas treinados (20 ± 5,1 anos; 70,8 ± 12,2 kg e 179,1 ± 7,2 cm) que realizaram os seguintes testes: um teste incremental para determinação do consumo máximo de oxigênio (VO2max), intensidade correspondente ao VO2max (IVO2max) e limiar anaeróbio (LAn); três testes para determinar o tlim a 95, 100 e 110%IVO2max; seis testes (duas intensidades vs. três cadências) até a exaustão voluntária na PC e 105%PC em diferentes cadências de pedalada (Cadpref-25%, Cadpref e Cadpref+25%) para determinar as respostas fisiológicas consumo de oxigênio (VO2), freqüência cardíaca (FC), ventilação pulmonar (VE), lactato sangüíneo ([Lac]), delta de lactato ([Lac]), componente lento da cinética do VO2 (CL) e tlim. A PC foi determinada pelo modelo linear potência vs. 1/tlim (P x 1/tlim). Na análise dos dados utilizou-se a estatística descritiva (média ± DP), o teste de Shapiro-Wilk para verificar a normalidade, a análise de variância one-way de medidas repetidas, a análise de variância two-way de medidas repetidas, teste post hoc de Bonferroni, o teste t de Student para amostras pareadas e o teste de correlação de Pearson. Foi adotado um nível de significância de 5%. Resultados: Os valores de VO2max, IVO2max, LAn, PC e 105%PC foram 66,7 ± 8,0 ml.kg-1.min-1, 345 ± 41 W, 254 ± 35 W, 294 ± 37 W e 308 ± 40 W, respectivamente. A PC e 105%PC corresponderam em média a aproximadamente 85 e 89%IVO2max, respectivamente. Os valores de Cadpref-25%, Cadpref e Cadpref+25% foram 73 ± 3 rpm, 98 ± 4 rpm e 122 ± 4 rpm na PC, e 74 ± 2 rpm, 99 ± 3 rpm e 123 ± 3 rpm em 105%PC, respectivamente. Os valores de VO2, FC, VE e [Lac] aumentaram significativamente com o aumento da cadência nas duas intensidades analisadas (PC e 105%PC). O [Lac] e o CL diferiram significantemente (p<0,05) na PC entre a Cadpref-25% e a Cadpref. O tlim no exercício realizado na Cadpref+25% foi significantemente (p<0,05) menor que na Cadpref e na Cadpref-25% em ambas as intensidades. Ao analisar o efeito da intensidade (PC vs. 105%PC) no tlim, foram encontradas diferenças significativas (p<0,05) para todas as cadências. O VO2max foi atingido na PC utilizando a Cadpref+25% e em 105%PC utilizando a Cadpref e a Cadpref+25%. Conclusão: Com base nos resultados encontrados, pode-se concluir que o exercício realizado na PC e em 105%PC por ciclistas treinados utilizando a Cadpref+25%, quando comparado com as Cadpref-25% e Cadpref, demanda um maior gasto energético e apresenta um menor tempo de sustentação nessas intensidades. Além disso, o VO2 determinado durante a PC atinge seus valores máximos ao final do exercício realizado na Cadpref+25% e o atingimento do VO2max é dependente da cadência no exercício a 105%PC
Thermally Stable Molybdenum Oxide Hole-Selective Contacts Deposited using Spatial Atomic Layer Deposition
No full textSub-stoichiometric MoO x has been identified as a viable replacement to p-type a-Si:H in hole-selective contacts to c-Si solar cells. Many groups have observed a strong tendency for the electrical properties of MoO x -based contacts to degrade during the standard contact formation anneal due to the addition of O vacancies in the MoO x . These O vacancies create defect levels within the bandgap and lowers the work function of the MoO x , which in turn affects the efficiency of hole-conduction through the contact. In this paper, we grow a thin tunneling SiO x layer over p-type c-Si via UV-ozone treatment, followed by a thin (∼5 nm) MoO x deposited using spatial atomic layer deposition. We show that the use of the high work function (5.01 eV) Nickel, as a replacement to the Aluminum contact, not only assists in efficient hole-transport, but also forms a thermally stable contact up to temperatures of 300°C with contact resistivities below 10 mΩ-cm 2
Engineered Interfaces Using Surface and Contact Passivation in Silicon Solar Cells
No full textSilicon solar cell passivation has evolved greatly, with recent approaches enabling interface engineering for carrier selectivity and effective suppression of recombination under contacted regions of the cell. Future advanced silicon solar cell designs will certainly adopt passivated contact approaches given the strong experimental evidence demonstrating their benefits. The ability to adjust the work function of the metal oxide interfacial tunnel layer, a critical parameter in determining the efficiency of the contact, has proven to be a valuable attractive attribute. However, widespread adoption of metal oxide passivated contact approaches will require a considerable amount of further work to understand the stability and long-term reliability of such structures. Much of the near-term work must focus on the role of oxygen vacancies in determining the work function and transport properties across the interfacial layer with additional focus on processing methods to engineer such interfaces for optimal silicon solar cell efficiency
Photon Management for Silicon Solar Cells featuring Hole-Selective Molybdenum Oxide Rear Contacts: An Optical Simulation Study
No full text
Edge-Defined Film-Fed Silicon Glass–Glass Modules on Florida Rooftop After 22 Years
No full textA set of four edge-defined film-fed growth (EFG) silicon modules from a ten-module system in Florida is measured after 22 years of exposure. Data here include current-voltage I-V, pseudo-I-V obtained using I-V and suns-Voc, carrier lifetime versus excess carrier density data, dark I-V, electroluminescence images at 0.1 and 1 times the nameplate short-circuit current, and visual images showing prominent defects. These data are part of the study published in https://onlinelibrary.wiley.com/doi/full/10.1002/pssr.202200215.
These data were obtained through work supported by the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE) under
the Solar Energy Technologies Office Agreement Numbers DE-EE0008172, DE-EE0008155, and DE-EE0009347. The authors would like to thank Donard Metzger of FSEC for bringing these modules to our attention and helping with installation and measurements
A Model of Mortgage Default
No full textThis paper solves a dynamic model of a household's decision to default on its mortgage, taking into account labor income, house price, inflation, and interest rate risk. Mortgage default is triggered by negative home equity, which results from declining house prices in a low inflation environment with large mortgage balances outstanding. Not all households with negative home equity default, however. The level of negative home equity that triggers default depends on the extent to which households are borrowing constrained. High loan-to-value ratios at mortgage origination increase the probability of negative home equity. High loan-to-income ratios also increase the probability of default by tightening borrowing constraints. Comparing mortgage types, adjustable-rate mortgage defaults occur when nominal interest rates increase and are substantially affected by idiosyncratic shocks to labor income. Fixed-rate mortgages default when interest rates and inflation are low, and create a higher probability of a default wave with a large number of defaults. Interest-only mortgages trade off an increased probability of negative home equity against a relaxation of borrowing constraints, but overall have the highest probability of a default wave.
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