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Thickness dependence of microcrystalline silicon solar cell properties
07 Alternative energy sources (solar energy) system is approximately 1.4. It clearly reveals that this system would be an effective way to reduce CO2 emissions and to utilize PV power generation as a-natural energy source.
02/01575 Performance of p-type silicon-oxide windows in amorphous silicon solar cell Matsumoto, Y. et al. Solar Energy Materials & Solar Cells, 2001, 66, (l-4), 163-170. a-SiO, films have been prepared using silane and pure oxygen as reactive gases in plasma CVD system. Diborane was introduced as a doping gas to obtain p-type conduction silicon oxide. Infrared absorption sectra show the incorporation of Si-0 stretch mode around 1000 cm-t. The optical bandgap increases with the oxygen to silane gas ratio, while the electrical conductivity decreases. Hydrogenated amorphous silicon solar cells have been fabricated using p-type a-SiO, with around I.85 eV optical bandgap and conductivity greater than IO-’ S/cm. The measured current-voltage characteristics of the solar cells under 100 mW/cm’ artificial light are V,, = 0.84 V. Jlc = 14.7 mA/cm’, FF = 0.635 with a conversion efftciency of 7.84%.
02/01578 Photoelectrochemical studies on [MnMoOz NCS)(Ox)s(HaO)z] (Ox = 6quinolinol): system 0 I solar energy conversion Edwin Suresh Raj, A.M. et al. International
a novel
Journal of Energy Research,
2000, 24, (IS), 1351-1358.
Photoelectrochemical studies were carried out on [MnMoOs(NCS)(Ox)s(HsO),] (Ox = 8-quinolinol) complex in aqueous dimethylformamide medium in a Honda cell. The system develooed a maximum potential of 335 mV when exposed to visible light ai 30°C and was found to be reversible. The photogalvanic behaviour has been further investigated by varying the pH, temperature and photosensitizers. When a temperature difference between the illuminated and dark halfcells was maintained, the system generated 410 mV at 60°C. A solidstate galvanic cell, developed using the complex mixed with tetracthylammonium perchlorate (TEAP), showed a maximum voltage of 25mV. A sandwich galvanic cell, constructed from transparent tin oxide-glass/complex/platinum, developed a maximum photovoltage of 88 mV when irradiated with a tungsten halogen lamp.
Properties of amorphous silicon solar cells fabricated from SiH& 02101577
Shimizu, S. et al. Solar Energy Marerials & Solar Cells, 2001, 66, (l-4) 289-295. Chlorinated intrinsic amorphous silicon films [a-Si:H(CI)] and solar cell i-layers were fabricated using electron cyclotron resonance-assisted chemical vapour deposition (ECR-CVD) and SiHrCls source gas. n-i-p solar cells -deposited on ZnO-coated SnOr substrates had poor photovoltaic performances despite the good electronic properties measured on the a-Si:H(Cl) films. improved open-circuit voltage (I’,) of 0.84 V and fill factor (FF) of 54% were observed in n-i-p solar cells by providing an n/i buffer layer and by using Ga-doped ZnO coated glass substrates. However, the FF improvement was still rather poor, which is thought to originate from high interface recombination in the ECR deposited solar cells. The V.,, and the FF showed much stable feature against light soaking. 02/01578 PV systems in urban environment Kurokawa, K. Solar Energy Materials & Solar Cells, 2001, 67, (l-4). 469-479. The paper describes PV applications in urban area en masse. When a large number of PV systems are introduced in the area, PV electricity will become very significant and overall optimization may be required for the total area. In terms of PV system configuration as a group as well as regional electricity supply network. Assuming these scenario options, recent trends are reviewed for residential zone, business area and Industrial application. Technical problems are also summarized for BIPV and electrical engineering.
02/01579 Solar cells with Cu(ln,_paX)S2 thin films prepared by sulfurization Ohashi,
T. et al. Solar Energy Materials
& Solar Cells, 2001, 67, (l-4),
225-230.
By rapid thermal processing of Cu/In/GaS precursors, good-quality CuIni.,Ga.& films are synthesized. By suppressing the formation of In-rich hillocks, homogeneous CuIn,.,Ga,S~ surfaces could be obtained. A conversion efficiency of -12% has been achieved using a relatively low (~1.2) Cu/In ratio. OR/O1580 Solar energy and global heat balance of city Roulet, C-A. Solar Energy, 2001, 70, (3), 255-261. The global energy balance of a city involves numerous energy flows and is rather complex. It includes, among others, the absorbed solar radiation and the energy fuels on one hand, and the heat loss to the environment - by radiation, convection and evaporation - on the other
hand, This balance generally results in a temperature in the town that is slightly higher than in the surrounding country. Using solar energy saves imported fuels on one hand, but increases the absorption of solar radiation on the other hand. Simple, steady state models are used to assess the channe of heat released to the environment when reolacine the use of clas&al fuels by solar powered plants, on both theglob; and city scale. The conclusion is that, in most cases, this will reduce the heat released to the environment. The exception is cooling, for which a good solar alternative does not exist today.
02/01581 Solar thermal process heating in industrial applications Karagiorgas, XVII
M. er al. A publication of lhe European Commission (DG for Energy, ALTENER Programme), CRES, 2000,
Industrial solar thermal installations in the 1980s had to face problems of Door aualitv and hieh maintenance reauirements. During the 1990s thd situation’began ‘to change and today in Greece yhere exist installations which are both economically attractive and offer significant energy saving and environmental benefits. Good potential for applications of solar thermal systems exist in the sectors: agrofood, textiles, chemicals and beverages. In this paper such systems are evaluated in economic terms in comparison with energy equivalent systems such as diesel, LPG, fuel 1500 and natural gas. Furthermore the development of local solar thermal markets is described and eight successful applications of solar thermal systems in Greek industry are described.
02/01582 Spatio-temporal variability of solar energy across a region: a statistical modelllng approach Glasbey, C.A. et ql. Solar Energy, 2001, 70, (4), 373-381. Solar energy collected at a number of discrete sites, which are dispersed over a geographical area, will exhibit both spatial and temporal variability. Being able to model this variability will have many applications, for example in controlling an electricity system that is supplied by decentralized PV arrays. This paper describes a statistical modelling study of solar data that were recorded over 2 years at a total of 22 sites in the city of Edinburgh. Scotland, and in the nearby Pentland hills. A spatio-temporal model is proposed for global irradiation on a horizontal plane: this incorporates the sum of two exponentials to model the decrease in covariance between sites with time lag, and a space-time term to model the combined dependence of covariance on time lag and easterly distance.
02/01583 Stablli of a-Si:H solar cells deposited by Artreatment or by E! R techniques Ohkawa, K. ef al. Solar Energy Materials & Solar Cells, 2001, 66, (l-4) 297-303. Stability against light soaking was studied for amorphous silicon (aSi:H) solar cells using three different i-layers; (a) device-quality a-Si:H (standard a-Si:H) with bandgap of 1.75 eV, (b) narrow bandgap (1.55 eV) a-Si:H fabricated by Ar* chemical annealing and (c) a-Si:H(CI) fabricated from SiHzCLr. Both the narrow bandgap a-Si:H and the aSi:HfCI) solar cells showed much imoroved stabilitv than that of the standard a-Si:H solar cells: e.g., fill iactor of the narrow bandgap aSi:H cell only slightly decreased from 56% to 53%, while that of the standard a-Si:H cell degraded from 62% to 51%. In addition, mobilitylifetime products of the a-Si:H(CI) cell also exhibited improved stability than that of the standard a-Si:H solar cell.
;2//;84
The present status and future of photovoltaic in
Zhao, Y. Solar Energy Materials & Solar Cells, 2001, 67, (l-4) 663671. The present status and future potential of PV development in China, including R&D activities, solar cell and module production, PV applications, its market and future potential are described in this paper.
02lO1585 Thickness dependence of microcrystalline silicon solar cell properties Vetterl, 0. er al. Solar Energy Materials & Solar Cells, 2001, 66, (l-4), 345-35 I. This paper addresses the performance of pin and nip solar cells with microcrystalline silicon (pc-Si:H) absorber layers of different thickness. Despite the reverse deposition sequence, the behaviour of both types of solar cells is found to be similar. Thicker absorber lavers vield hieher short-circuit currents, which can be fully attributed’to an enha&ed optical absorption. Open-circuit voltage V, and till factor FF decrease with increasing thickness, showing limitations of the bulk material. As a result of these two contrary effects the efficiency o varies only weakly for absorber layers of ~1-4 pm thickness, yielding maximum values up to 8.1 %. For a-si:H/pc-Si:H stacked solar cells an initial efficiency of 12% has been obtained.
Fuel and Energy Abstracts
May 2002
201
02/01575 Performance of p-type silicon-oxide windows in amorphous silicon solar cell Matsumoto, Y. et al. Solar Energy Materials & Solar Cells, 2001, 66, (l-4), 163-170. a-SiO, films have been prepared using silane and pure oxygen as reactive gases in plasma CVD system. Diborane was introduced as a doping gas to obtain p-type conduction silicon oxide. Infrared absorption sectra show the incorporation of Si-0 stretch mode around 1000 cm-t. The optical bandgap increases with the oxygen to silane gas ratio, while the electrical conductivity decreases. Hydrogenated amorphous silicon solar cells have been fabricated using p-type a-SiO, with around I.85 eV optical bandgap and conductivity greater than IO-’ S/cm. The measured current-voltage characteristics of the solar cells under 100 mW/cm’ artificial light are V,, = 0.84 V. Jlc = 14.7 mA/cm’, FF = 0.635 with a conversion efftciency of 7.84%.
02/01578 Photoelectrochemical studies on [MnMoOz NCS)(Ox)s(HaO)z] (Ox = 6quinolinol): system 0 I solar energy conversion Edwin Suresh Raj, A.M. et al. International
a novel
Journal of Energy Research,
2000, 24, (IS), 1351-1358.
Photoelectrochemical studies were carried out on [MnMoOs(NCS)(Ox)s(HsO),] (Ox = 8-quinolinol) complex in aqueous dimethylformamide medium in a Honda cell. The system develooed a maximum potential of 335 mV when exposed to visible light ai 30°C and was found to be reversible. The photogalvanic behaviour has been further investigated by varying the pH, temperature and photosensitizers. When a temperature difference between the illuminated and dark halfcells was maintained, the system generated 410 mV at 60°C. A solidstate galvanic cell, developed using the complex mixed with tetracthylammonium perchlorate (TEAP), showed a maximum voltage of 25mV. A sandwich galvanic cell, constructed from transparent tin oxide-glass/complex/platinum, developed a maximum photovoltage of 88 mV when irradiated with a tungsten halogen lamp.
Properties of amorphous silicon solar cells fabricated from SiH& 02101577
Shimizu, S. et al. Solar Energy Marerials & Solar Cells, 2001, 66, (l-4) 289-295. Chlorinated intrinsic amorphous silicon films [a-Si:H(CI)] and solar cell i-layers were fabricated using electron cyclotron resonance-assisted chemical vapour deposition (ECR-CVD) and SiHrCls source gas. n-i-p solar cells -deposited on ZnO-coated SnOr substrates had poor photovoltaic performances despite the good electronic properties measured on the a-Si:H(Cl) films. improved open-circuit voltage (I’,) of 0.84 V and fill factor (FF) of 54% were observed in n-i-p solar cells by providing an n/i buffer layer and by using Ga-doped ZnO coated glass substrates. However, the FF improvement was still rather poor, which is thought to originate from high interface recombination in the ECR deposited solar cells. The V.,, and the FF showed much stable feature against light soaking. 02/01578 PV systems in urban environment Kurokawa, K. Solar Energy Materials & Solar Cells, 2001, 67, (l-4). 469-479. The paper describes PV applications in urban area en masse. When a large number of PV systems are introduced in the area, PV electricity will become very significant and overall optimization may be required for the total area. In terms of PV system configuration as a group as well as regional electricity supply network. Assuming these scenario options, recent trends are reviewed for residential zone, business area and Industrial application. Technical problems are also summarized for BIPV and electrical engineering.
02/01579 Solar cells with Cu(ln,_paX)S2 thin films prepared by sulfurization Ohashi,
T. et al. Solar Energy Materials
& Solar Cells, 2001, 67, (l-4),
225-230.
By rapid thermal processing of Cu/In/GaS precursors, good-quality CuIni.,Ga.& films are synthesized. By suppressing the formation of In-rich hillocks, homogeneous CuIn,.,Ga,S~ surfaces could be obtained. A conversion efficiency of -12% has been achieved using a relatively low (~1.2) Cu/In ratio. OR/O1580 Solar energy and global heat balance of city Roulet, C-A. Solar Energy, 2001, 70, (3), 255-261. The global energy balance of a city involves numerous energy flows and is rather complex. It includes, among others, the absorbed solar radiation and the energy fuels on one hand, and the heat loss to the environment - by radiation, convection and evaporation - on the other
hand, This balance generally results in a temperature in the town that is slightly higher than in the surrounding country. Using solar energy saves imported fuels on one hand, but increases the absorption of solar radiation on the other hand. Simple, steady state models are used to assess the channe of heat released to the environment when reolacine the use of clas&al fuels by solar powered plants, on both theglob; and city scale. The conclusion is that, in most cases, this will reduce the heat released to the environment. The exception is cooling, for which a good solar alternative does not exist today.
02/01581 Solar thermal process heating in industrial applications Karagiorgas, XVII
M. er al. A publication of lhe European Commission (DG for Energy, ALTENER Programme), CRES, 2000,
Industrial solar thermal installations in the 1980s had to face problems of Door aualitv and hieh maintenance reauirements. During the 1990s thd situation’began ‘to change and today in Greece yhere exist installations which are both economically attractive and offer significant energy saving and environmental benefits. Good potential for applications of solar thermal systems exist in the sectors: agrofood, textiles, chemicals and beverages. In this paper such systems are evaluated in economic terms in comparison with energy equivalent systems such as diesel, LPG, fuel 1500 and natural gas. Furthermore the development of local solar thermal markets is described and eight successful applications of solar thermal systems in Greek industry are described.
02/01582 Spatio-temporal variability of solar energy across a region: a statistical modelllng approach Glasbey, C.A. et ql. Solar Energy, 2001, 70, (4), 373-381. Solar energy collected at a number of discrete sites, which are dispersed over a geographical area, will exhibit both spatial and temporal variability. Being able to model this variability will have many applications, for example in controlling an electricity system that is supplied by decentralized PV arrays. This paper describes a statistical modelling study of solar data that were recorded over 2 years at a total of 22 sites in the city of Edinburgh. Scotland, and in the nearby Pentland hills. A spatio-temporal model is proposed for global irradiation on a horizontal plane: this incorporates the sum of two exponentials to model the decrease in covariance between sites with time lag, and a space-time term to model the combined dependence of covariance on time lag and easterly distance.
02/01583 Stablli of a-Si:H solar cells deposited by Artreatment or by E! R techniques Ohkawa, K. ef al. Solar Energy Materials & Solar Cells, 2001, 66, (l-4) 297-303. Stability against light soaking was studied for amorphous silicon (aSi:H) solar cells using three different i-layers; (a) device-quality a-Si:H (standard a-Si:H) with bandgap of 1.75 eV, (b) narrow bandgap (1.55 eV) a-Si:H fabricated by Ar* chemical annealing and (c) a-Si:H(CI) fabricated from SiHzCLr. Both the narrow bandgap a-Si:H and the aSi:HfCI) solar cells showed much imoroved stabilitv than that of the standard a-Si:H solar cells: e.g., fill iactor of the narrow bandgap aSi:H cell only slightly decreased from 56% to 53%, while that of the standard a-Si:H cell degraded from 62% to 51%. In addition, mobilitylifetime products of the a-Si:H(CI) cell also exhibited improved stability than that of the standard a-Si:H solar cell.
;2//;84
The present status and future of photovoltaic in
Zhao, Y. Solar Energy Materials & Solar Cells, 2001, 67, (l-4) 663671. The present status and future potential of PV development in China, including R&D activities, solar cell and module production, PV applications, its market and future potential are described in this paper.
02lO1585 Thickness dependence of microcrystalline silicon solar cell properties Vetterl, 0. er al. Solar Energy Materials & Solar Cells, 2001, 66, (l-4), 345-35 I. This paper addresses the performance of pin and nip solar cells with microcrystalline silicon (pc-Si:H) absorber layers of different thickness. Despite the reverse deposition sequence, the behaviour of both types of solar cells is found to be similar. Thicker absorber lavers vield hieher short-circuit currents, which can be fully attributed’to an enha&ed optical absorption. Open-circuit voltage V, and till factor FF decrease with increasing thickness, showing limitations of the bulk material. As a result of these two contrary effects the efficiency o varies only weakly for absorber layers of ~1-4 pm thickness, yielding maximum values up to 8.1 %. For a-si:H/pc-Si:H stacked solar cells an initial efficiency of 12% has been obtained.
Fuel and Energy Abstracts
May 2002
201