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03123 Substrates for thin crystalline silicon solar cells
07
Alternative energy sources (wind energy)
been determined. The usual equations, however, cannot fit some cells, perhaps because they are too approximated or due to the presence of other mechanisms. This work attempts to explain these mechanisms and correlate them with the characteristics of the device. In some cases, trap-assisted tunnelling current and field-assisted recombination had to be added to the usual two-exponential model (diffusion and recombination). The influence of the material on these currents has also been investigated. 9alO3114 Nontracking solar concentrators Spirkl, W. et al. Solar Energy, 1998, 62, (2) 113-120. The theoretical upper limit for the concentration of direct solar radiation at low latitudes has been derived with non-tracking concentrators from the projected solid angle sampled by the apparent motion of the sun, for the case where the energy efficiency is referred to the energy incident on the entrance aperture. The optimal acceptance is determined as a function of direction and time, which means rejecting the lower density radiation and switching off the device when losses would be higher than gains. Just as a device may gain concentration by rejecting radiation from certain directions, it can also gain by not operating at all, thus avoiding losses at certain times. Trough-type systems, which have translational symmetry, cannot be ideal non-tracking concentrators, but for low losses they perform only slightly worse than general three-dimensional concentrators.
On the ideal performance of solar cells with lsrger90iQ3115 than-unity quantum efficiency
De Vos, A. and Desoete, B. Solar Energy Materials and Solar Cells, 1998, 51, (3/4), 413-424. The performance of an ideal solar cell is investigated. The possibility of pair generation by impact ionization such that one incident photon can give rise to more than one electron-hole pair, is taken into account. 98103116
Passive solar design for Tasmania: the value of
sunspaces
Todd, .I. J. Solar Progress, 1997, 18, (4) 7-10. The majority of Tasmanian buildings, both private homes and commercial buildings, experience poor thermal performance. Despite recommendations by groups such as ANZSES, few Tasmanian homes use solar heating. These groups claim that it is both practical and comfortable. This article examines the reasons why solar heating is not used more widely in Tasmania.
Preparation of thin films of polycrystalline CdSe for 981931i 7 solar energy conversion II. Experimental
Gruszecki, T. and Holmstrom, B. Solar Energy Materials and Solar Cells, 1998, 51, (3/4), 243-253. In a bath containing CdS04, HzSeOs, and Hz S04, polycrystalline n-CdSe films were prepared onto titanium substrates by cathodic deposition. The objective was to obtain efficient photoelectrodes in a photoelectrochemical cell. With regard to both the problem of obtaining reproducible results and to the optimization of electrode performance, preparation procedures were evaluated. A number of factors were studied, including preparation of the surface of the titanium and the cadmium electrodes prior to deposition, composition of the plating solution, current density, stirring, time of deposition, post-deposition heat treatment, and electrode etching.
98103118 Production of cuprous oxide, a solar cell material, by thermal oxidation and a study of its physical and electrical properties Muss, A. 0. et al. Solar Energy Materials and Solar Cells, 1998, 51, (3/4), 305-316. As a non stoichiometric defect semiconductor, it is suggested that cuprous oxide (CuzO) could be utilized for the fabrication of low-cost solar cells. Between 200 and 1050°C. copper foil samples were oxidized in air. The oxide films grown were then investigated by means of both XRD and SEM. The electrical characteristics of CuzO films were analysed by means of the hot-probe thermoelectric method, resistivity and mobility measurements. The results are presented in detail.
Quantum-efficiency hydrogen-alloy-based solar cells
98103119
measurements
on carbon-
Maldei, M. and Ingram, D. C. Solar Energy Materials and Solar Cells, 1998, 51, (3/4), 433-440. Amorphous hydrogenated carbon (a-C : H) has been used as the primary semi-conducting material in some solar cell devices. These devices clearly demonstrate photovoltaic behaviour as determined by their I-V curves. Maximum quantum efficiency response is exhibited by these solar cells in the ultraviolet region. Using the measured quantum efficiency curves the short-circuit currents for a global AM 1.5 spectrum at an irradiance of 1000 W/m2 have been calculated and the values were found to be comparable to the short-circuit currents measured.
The role of the ZnO buffer layer in Al/S1 interdlffusion In a-Si : H solar cells on flexible substrates
90l03120
Saunderson, J. D. et al. Solar Energy Materials and Solar Cells, 1998, 51, (3/ 4), 425-432. The paper presents a study on the interdiffusion of Al and o-Si:H, occurring in cells grown on a KAPTON/AI substrate. The cell parameters of a series of cells grown at temperatures ranging from 100 to 200°C are presented for KAPTON/AI and KAPTON/AI/ZnO substrates, where a thin
299
Fuel and Energy Abstracts
July 1999
ZnO buffer layer was inserted for the latter series of substrates. This buffer layer results in a significant increase in cell efficiency. SIMS and SXPS depth profiles illustrate that cells grown on substrates without the ZnO layer are destroyed as a result of the interdiffusion of a-Si:H and Al and that the presence of the ZnO buffer layer impedes this process. Apart from the well-known enhanced reflectance and resulting improved cell characteristics caused by the insertion of this buffer layer, the authors claim that the main effect of the buffer layer (in cells grown on aluminized flexible substrates) is to impede the interdiffusion of Al and a-Si:H at the semiconductor/metal interface.
98lo3121 Sizing of solar supplemented liquid and ah heating systems for the treatment of vanilla
Ratobison, R. et al. Solar Energy, 1998, 62, (2). 131-138. Three different configurations of solar supplemented systems for simultaneous production of hot air and hot water needed during the processing of vanilla are studied. Correlations for the monthly solar fraction versus two dimensionless factors defined in terms of physical characteristics of the system have been developed. The various solar systems been evaluated against each other from a techno-economic viewpoint and correlations for the optimal system have been proposed which directly relate the mass of the product to be dried with the area of the solar collector.
9ala3122
A solar-driven combined cycle power plant Kribus, A. Solar Energy, 1998, 62, (2), 121-129. Presented are the main results of a feasibility study of a combined cycle electricity generation plant, driven by highly concentrated solar energy and high-temperature central receiver technology. A new solar power plant concept incorporated new developments in solar tower optics, highperformance air receivers and solar-to-gas turbine interface. The new design features 100% solar operation at design point, and hybrid (solar and fuel) operation for maximum dispatchability. Software tools were developed to simulate the new system configuration, evaluate its performance and cost, and optimize its design. System evaluation and optimization were carried out for two power levels. The new system design was shown to have cost and performance advantages over other solar thermal concepts and to be competitive against conventional fuel power plants in certain markets even without government subsidies. 9am3123 Substrates for thin crystalline silicon solar cells Blakers, A. W. Solar Energy Materials and Solar Cells, 1998, 51, (3/4), 385392. A compromise between cost and quality is necessary in the choice of substrate for thin crystalline silicon solar cells. Three generic substrate types exist: a transparent substrate (such as glass), an opaque substrate (such as a ceramic or metal) and low-cost multi-crystalline silicon. Glass has the advantage of eliminating absorption within the substrate. However, the larger effective diffusion length, the improved surface passivation and the increased process flexibility obtainable with an opaque substrate, particularly low-cost multicrystalline silicon, may considerably outweigh the modest optical benefits of a transparent substrate. 90lQ3124 Two- and three-dimensional optical carrier generstion determination in crystalline silicon solar cells
Zechner, C. et al. Solar Energy Materials and Solar Cells, 1998, 51, (3/4), 255-261. The paper gives details of two- and three-dimensional analyses of the distribution of optically generated charge carriers in textured crystalline silicon solar cells of arbitrary geometry. Developed for that purpose, the simulation algorithm is based on geometrical optics and ray tracing. It determines the dominant contributions to the optical generation within textured silicon exactly. Using a Monte-Carlo simulation, the contribution of weakly absorbed long-wavelength photons is calculated. The presented algorithm is fast and accurate and can also be used to calculate reflectance and transmittance spectra in excellent agreement with measurements. Twoand three-dimensional generation profiles in single- and double-sided textured solar cells are presented and discussed in detail. The presented algorithm is compared with a pure Monte-Carlo algorithm.
Wind Energy 99iO3125
Fitting wind speed distributions: a case study
Garcia, A. et al. Solar Energy, 1998 ,62, (2), 139-144. In order to show the shape of a potential model, wind speed data is represented in the form of frequency curves. The Weibull and Lognormal models are used for this purpose, with hourly mean wind speed data. This study deals with the estimation of the annual Weibull and Lognormal parameters from 20 locations in Navarre. The suitability of both distributions is judged from the RZ coefficient with a linear regression for the Weibull distribution and a non-linear regression for the Lognormal distribution. Good fit was found with both approaches, achieving better results for the Weibull distribution. A comparison between the estimation and the production for a wind farm is made.
Alternative energy sources (wind energy)
been determined. The usual equations, however, cannot fit some cells, perhaps because they are too approximated or due to the presence of other mechanisms. This work attempts to explain these mechanisms and correlate them with the characteristics of the device. In some cases, trap-assisted tunnelling current and field-assisted recombination had to be added to the usual two-exponential model (diffusion and recombination). The influence of the material on these currents has also been investigated. 9alO3114 Nontracking solar concentrators Spirkl, W. et al. Solar Energy, 1998, 62, (2) 113-120. The theoretical upper limit for the concentration of direct solar radiation at low latitudes has been derived with non-tracking concentrators from the projected solid angle sampled by the apparent motion of the sun, for the case where the energy efficiency is referred to the energy incident on the entrance aperture. The optimal acceptance is determined as a function of direction and time, which means rejecting the lower density radiation and switching off the device when losses would be higher than gains. Just as a device may gain concentration by rejecting radiation from certain directions, it can also gain by not operating at all, thus avoiding losses at certain times. Trough-type systems, which have translational symmetry, cannot be ideal non-tracking concentrators, but for low losses they perform only slightly worse than general three-dimensional concentrators.
On the ideal performance of solar cells with lsrger90iQ3115 than-unity quantum efficiency
De Vos, A. and Desoete, B. Solar Energy Materials and Solar Cells, 1998, 51, (3/4), 413-424. The performance of an ideal solar cell is investigated. The possibility of pair generation by impact ionization such that one incident photon can give rise to more than one electron-hole pair, is taken into account. 98103116
Passive solar design for Tasmania: the value of
sunspaces
Todd, .I. J. Solar Progress, 1997, 18, (4) 7-10. The majority of Tasmanian buildings, both private homes and commercial buildings, experience poor thermal performance. Despite recommendations by groups such as ANZSES, few Tasmanian homes use solar heating. These groups claim that it is both practical and comfortable. This article examines the reasons why solar heating is not used more widely in Tasmania.
Preparation of thin films of polycrystalline CdSe for 981931i 7 solar energy conversion II. Experimental
Gruszecki, T. and Holmstrom, B. Solar Energy Materials and Solar Cells, 1998, 51, (3/4), 243-253. In a bath containing CdS04, HzSeOs, and Hz S04, polycrystalline n-CdSe films were prepared onto titanium substrates by cathodic deposition. The objective was to obtain efficient photoelectrodes in a photoelectrochemical cell. With regard to both the problem of obtaining reproducible results and to the optimization of electrode performance, preparation procedures were evaluated. A number of factors were studied, including preparation of the surface of the titanium and the cadmium electrodes prior to deposition, composition of the plating solution, current density, stirring, time of deposition, post-deposition heat treatment, and electrode etching.
98103118 Production of cuprous oxide, a solar cell material, by thermal oxidation and a study of its physical and electrical properties Muss, A. 0. et al. Solar Energy Materials and Solar Cells, 1998, 51, (3/4), 305-316. As a non stoichiometric defect semiconductor, it is suggested that cuprous oxide (CuzO) could be utilized for the fabrication of low-cost solar cells. Between 200 and 1050°C. copper foil samples were oxidized in air. The oxide films grown were then investigated by means of both XRD and SEM. The electrical characteristics of CuzO films were analysed by means of the hot-probe thermoelectric method, resistivity and mobility measurements. The results are presented in detail.
Quantum-efficiency hydrogen-alloy-based solar cells
98103119
measurements
on carbon-
Maldei, M. and Ingram, D. C. Solar Energy Materials and Solar Cells, 1998, 51, (3/4), 433-440. Amorphous hydrogenated carbon (a-C : H) has been used as the primary semi-conducting material in some solar cell devices. These devices clearly demonstrate photovoltaic behaviour as determined by their I-V curves. Maximum quantum efficiency response is exhibited by these solar cells in the ultraviolet region. Using the measured quantum efficiency curves the short-circuit currents for a global AM 1.5 spectrum at an irradiance of 1000 W/m2 have been calculated and the values were found to be comparable to the short-circuit currents measured.
The role of the ZnO buffer layer in Al/S1 interdlffusion In a-Si : H solar cells on flexible substrates
90l03120
Saunderson, J. D. et al. Solar Energy Materials and Solar Cells, 1998, 51, (3/ 4), 425-432. The paper presents a study on the interdiffusion of Al and o-Si:H, occurring in cells grown on a KAPTON/AI substrate. The cell parameters of a series of cells grown at temperatures ranging from 100 to 200°C are presented for KAPTON/AI and KAPTON/AI/ZnO substrates, where a thin
299
Fuel and Energy Abstracts
July 1999
ZnO buffer layer was inserted for the latter series of substrates. This buffer layer results in a significant increase in cell efficiency. SIMS and SXPS depth profiles illustrate that cells grown on substrates without the ZnO layer are destroyed as a result of the interdiffusion of a-Si:H and Al and that the presence of the ZnO buffer layer impedes this process. Apart from the well-known enhanced reflectance and resulting improved cell characteristics caused by the insertion of this buffer layer, the authors claim that the main effect of the buffer layer (in cells grown on aluminized flexible substrates) is to impede the interdiffusion of Al and a-Si:H at the semiconductor/metal interface.
98lo3121 Sizing of solar supplemented liquid and ah heating systems for the treatment of vanilla
Ratobison, R. et al. Solar Energy, 1998, 62, (2). 131-138. Three different configurations of solar supplemented systems for simultaneous production of hot air and hot water needed during the processing of vanilla are studied. Correlations for the monthly solar fraction versus two dimensionless factors defined in terms of physical characteristics of the system have been developed. The various solar systems been evaluated against each other from a techno-economic viewpoint and correlations for the optimal system have been proposed which directly relate the mass of the product to be dried with the area of the solar collector.
9ala3122
A solar-driven combined cycle power plant Kribus, A. Solar Energy, 1998, 62, (2), 121-129. Presented are the main results of a feasibility study of a combined cycle electricity generation plant, driven by highly concentrated solar energy and high-temperature central receiver technology. A new solar power plant concept incorporated new developments in solar tower optics, highperformance air receivers and solar-to-gas turbine interface. The new design features 100% solar operation at design point, and hybrid (solar and fuel) operation for maximum dispatchability. Software tools were developed to simulate the new system configuration, evaluate its performance and cost, and optimize its design. System evaluation and optimization were carried out for two power levels. The new system design was shown to have cost and performance advantages over other solar thermal concepts and to be competitive against conventional fuel power plants in certain markets even without government subsidies. 9am3123 Substrates for thin crystalline silicon solar cells Blakers, A. W. Solar Energy Materials and Solar Cells, 1998, 51, (3/4), 385392. A compromise between cost and quality is necessary in the choice of substrate for thin crystalline silicon solar cells. Three generic substrate types exist: a transparent substrate (such as glass), an opaque substrate (such as a ceramic or metal) and low-cost multi-crystalline silicon. Glass has the advantage of eliminating absorption within the substrate. However, the larger effective diffusion length, the improved surface passivation and the increased process flexibility obtainable with an opaque substrate, particularly low-cost multicrystalline silicon, may considerably outweigh the modest optical benefits of a transparent substrate. 90lQ3124 Two- and three-dimensional optical carrier generstion determination in crystalline silicon solar cells
Zechner, C. et al. Solar Energy Materials and Solar Cells, 1998, 51, (3/4), 255-261. The paper gives details of two- and three-dimensional analyses of the distribution of optically generated charge carriers in textured crystalline silicon solar cells of arbitrary geometry. Developed for that purpose, the simulation algorithm is based on geometrical optics and ray tracing. It determines the dominant contributions to the optical generation within textured silicon exactly. Using a Monte-Carlo simulation, the contribution of weakly absorbed long-wavelength photons is calculated. The presented algorithm is fast and accurate and can also be used to calculate reflectance and transmittance spectra in excellent agreement with measurements. Twoand three-dimensional generation profiles in single- and double-sided textured solar cells are presented and discussed in detail. The presented algorithm is compared with a pure Monte-Carlo algorithm.
Wind Energy 99iO3125
Fitting wind speed distributions: a case study
Garcia, A. et al. Solar Energy, 1998 ,62, (2), 139-144. In order to show the shape of a potential model, wind speed data is represented in the form of frequency curves. The Weibull and Lognormal models are used for this purpose, with hourly mean wind speed data. This study deals with the estimation of the annual Weibull and Lognormal parameters from 20 locations in Navarre. The suitability of both distributions is judged from the RZ coefficient with a linear regression for the Weibull distribution and a non-linear regression for the Lognormal distribution. Good fit was found with both approaches, achieving better results for the Weibull distribution. A comparison between the estimation and the production for a wind farm is made.