Pub Date : 2012-06-03DOI: 10.1109/PVSC.2012.6318148
S. Kuo, Jui‐Fu Yang, F. Lai, Chun-Jung Lin
Precursors of the Cu2ZnSnSe4 (CZTSe) absorber were deposition on Mo/glass substrate by radio-frequency (RF) magnetron sputtering at room temperature. The precursors were converted into CZTSe absorber by annealing in the selenium vapors at the substrate temperature of 550°C. CZTSe films have been characterized in detail using X-ray diffraction (XRD), Raman spectroscopy, photo luminescence (PL), energy dispersive spectrometer (EDS), and solar simulator. It was found that the structural and optical properties of CZTSe films. The p-type CZTSe absorber shows a peak below 0.9 eV at room temperature. Solar cells with the AZO/ZnO/CdS/CZTSe/Mo showed the best conversion efficiency of 1.78% for 0.13 cm2 with Voc= 0.21 V, Jsc= 27.1 mA/cm2, and FF= 31.3%.
{"title":"Growth of Cu2ZnSnSe4 thin films by selenization of magnetron sputtered precursors for solar cells","authors":"S. Kuo, Jui‐Fu Yang, F. Lai, Chun-Jung Lin","doi":"10.1109/PVSC.2012.6318148","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6318148","url":null,"abstract":"Precursors of the Cu2ZnSnSe4 (CZTSe) absorber were deposition on Mo/glass substrate by radio-frequency (RF) magnetron sputtering at room temperature. The precursors were converted into CZTSe absorber by annealing in the selenium vapors at the substrate temperature of 550°C. CZTSe films have been characterized in detail using X-ray diffraction (XRD), Raman spectroscopy, photo luminescence (PL), energy dispersive spectrometer (EDS), and solar simulator. It was found that the structural and optical properties of CZTSe films. The p-type CZTSe absorber shows a peak below 0.9 eV at room temperature. Solar cells with the AZO/ZnO/CdS/CZTSe/Mo showed the best conversion efficiency of 1.78% for 0.13 cm2 with Voc= 0.21 V, Jsc= 27.1 mA/cm2, and FF= 31.3%.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":"49 1","pages":"002688-002691"},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79247396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-06-03DOI: 10.1109/PVSC.2012.6318197
L. Ciabattoni, M. Grisostomi, G. Ippoliti, S. Longhi, E. Mainardi
The paper deals with the forecast of the power production for three different PhotoVoltaic (PV) plants using an on-line self learning prediction algorithm. The plants are located in Italy at different latitudes. This learning algorithm is based on a radial basis function (RBF) network and combines the growing criterion and the pruning strategy of the minimal resource allocating network technique. Its on-line learning mechanism gives the chance to avoid the initial training of the NN with a large data set. The performances of the algorithm are tested on the three PV plants with different peak power, panel's materials, orientation and tilting angle. Results are compared to a classical RBF neural network.
{"title":"Online tuned neural networks for PV plant production forecasting","authors":"L. Ciabattoni, M. Grisostomi, G. Ippoliti, S. Longhi, E. Mainardi","doi":"10.1109/PVSC.2012.6318197","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6318197","url":null,"abstract":"The paper deals with the forecast of the power production for three different PhotoVoltaic (PV) plants using an on-line self learning prediction algorithm. The plants are located in Italy at different latitudes. This learning algorithm is based on a radial basis function (RBF) network and combines the growing criterion and the pruning strategy of the minimal resource allocating network technique. Its on-line learning mechanism gives the chance to avoid the initial training of the NN with a large data set. The performances of the algorithm are tested on the three PV plants with different peak power, panel's materials, orientation and tilting angle. Results are compared to a classical RBF neural network.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":"96 1","pages":"002916-002921"},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84421195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-06-03DOI: 10.1109/PVSC.2012.6318183
T. Nakamura, M. Imaizumi, S. Sato, T. Ohshima
Roensch et al. recently proposed a new method of estimating the current-voltage (IV) characteristics of subcells in a multi-junction (MJ) solar cell by using electroluminescence (EL). The estimated IV characteristics of a proton-irradiated MJ solar cell from the IV curve obtained from each subcell agreed well with the actual dark IV (DIV) and light IV (LIV) characteristics, except for series resistance (Rs) and shunt resistance (Rsh). This method can also clarify Rs of a MJ cells and Rsh of subcells through circuit simulation program. In this work, we applied this method to InGaP/GaAs dual-junction (2J) solar cells in order to obtain the IV characteristics of the InGaP top subcells and GaAs bottom subcells before and after proton irradiation with various fluences. In addition, we succeeded to predict the degradation curve of maximum power (Pmax) of the 2J solar cell where the current-limiting subcell changes from InGaP to GaAs subcell.
{"title":"Change in I–V characteristics of subcells in a multi-junction solar cell due to radiation irradiation","authors":"T. Nakamura, M. Imaizumi, S. Sato, T. Ohshima","doi":"10.1109/PVSC.2012.6318183","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6318183","url":null,"abstract":"Roensch et al. recently proposed a new method of estimating the current-voltage (IV) characteristics of subcells in a multi-junction (MJ) solar cell by using electroluminescence (EL). The estimated IV characteristics of a proton-irradiated MJ solar cell from the IV curve obtained from each subcell agreed well with the actual dark IV (DIV) and light IV (LIV) characteristics, except for series resistance (Rs) and shunt resistance (Rsh). This method can also clarify Rs of a MJ cells and Rsh of subcells through circuit simulation program. In this work, we applied this method to InGaP/GaAs dual-junction (2J) solar cells in order to obtain the IV characteristics of the InGaP top subcells and GaAs bottom subcells before and after proton irradiation with various fluences. In addition, we succeeded to predict the degradation curve of maximum power (Pmax) of the 2J solar cell where the current-limiting subcell changes from InGaP to GaAs subcell.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":"14 1","pages":"002846-002850"},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84493726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-06-03DOI: 10.1109/PVSC.2012.6317986
C. Arredondo, W. Vallejo, J. Hernández, G. Gordillo
In this work In(O,OH)S thin films were deposited on AgInS2 thin films for the system absorbent-layer/buffer-layer to be used in two junctions tandem and/or in single junction solar cells. AgInS2 layers were grown by co-evaporation from metal precursors in a two stage process, and In(O,OH)S thin films were deposited by chemical bath deposition. X-ray diffraction measurements indicated that AgInS2 thin films grown with chalcopyrite structure; and In(O,OH)S films grown with polycrystalline structure. It was also found that the AgInS2 films presented p-type conductivity, a high absorption coefficient (greater than 104 cm-1) and an energy band gap (Eg) of 1.95 eV, and In(O,OH),S thin films presented Eg about 3.01 eV. The results indicate that the developed system can be used in single junction solar cells, and in two junctions tandem solar cell as top cell.
{"title":"In(O,OH)S/AgInS2 absorbent layer/buffer layer system for thin film solar cells","authors":"C. Arredondo, W. Vallejo, J. Hernández, G. Gordillo","doi":"10.1109/PVSC.2012.6317986","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6317986","url":null,"abstract":"In this work In(O,OH)S thin films were deposited on AgInS2 thin films for the system absorbent-layer/buffer-layer to be used in two junctions tandem and/or in single junction solar cells. AgInS2 layers were grown by co-evaporation from metal precursors in a two stage process, and In(O,OH)S thin films were deposited by chemical bath deposition. X-ray diffraction measurements indicated that AgInS2 thin films grown with chalcopyrite structure; and In(O,OH)S films grown with polycrystalline structure. It was also found that the AgInS2 films presented p-type conductivity, a high absorption coefficient (greater than 104 cm-1) and an energy band gap (Eg) of 1.95 eV, and In(O,OH),S thin films presented Eg about 3.01 eV. The results indicate that the developed system can be used in single junction solar cells, and in two junctions tandem solar cell as top cell.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":"29 1","pages":"001988-001991"},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84868717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-06-03DOI: 10.1109/PVSC.2012.6317810
Yang Yang, H. Mehrvarz, S. Pillai, M. Green, H. Kampwerth, A. Ho-baillie
Rear surface reflector of solar cell is designed to improve light collection capacity by allowing the low energy photons to go through multiple bounces inside the solar device before escaping. In this paper, we investigate the thickness effect of rear SiO2 surface passivation layer on both optical and electrical properties of front-planar high efficiency PERT (Passivated Emitter and Rear Totally-Diffused) solar cells. Two kinds of metal reflectors are fabricated: the conventional planar reflectors by evaporated Al and the novel scattering reflectors by self assembled Ag nanoparticles. We find that the thickness dependence of rear SiO2 layer (from 8 nm - 134 nm) on photocurrent shows an asymmetry for planar and scattering reflectors, moreover, the scattering reflectors perform much better than the planar reflectors under all tested SiO2 thicknesses. A maximum current enhancement (calculated from wavelength 900 nm to 1200 nm) of 12.1% is presented for planar reflector with 134 nm SiO2 film, and 18.4% for scattering reflector with the optimized 19 nm rear SiO2 film. Additionally, by adding a detached metal mirror, the maximum current enhancement from scattering reflector jumps to 27.0%. Effective optical path length Z is calculated to study the light trapping (optical properties) under various SiO2 thicknesses for both reflectors. Diffusion length L is calculated to track the electrical performance. It is shown that thicker SiO2 is of benefit for both optical and electrical properties when planar Al reflector is used. However, for scattering reflectors, thinner SiO2 is preferable for optical enhancement, but thicker SiO2 is desirable for electrical gain. 19 nm SiO2 is found to be the best choice for cells with scattering reflectors, considering both effects.
{"title":"The effect of rear surface passivation layer thickness on high efficiency solar cells with planar and scattering metal reflectors","authors":"Yang Yang, H. Mehrvarz, S. Pillai, M. Green, H. Kampwerth, A. Ho-baillie","doi":"10.1109/PVSC.2012.6317810","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6317810","url":null,"abstract":"Rear surface reflector of solar cell is designed to improve light collection capacity by allowing the low energy photons to go through multiple bounces inside the solar device before escaping. In this paper, we investigate the thickness effect of rear SiO2 surface passivation layer on both optical and electrical properties of front-planar high efficiency PERT (Passivated Emitter and Rear Totally-Diffused) solar cells. Two kinds of metal reflectors are fabricated: the conventional planar reflectors by evaporated Al and the novel scattering reflectors by self assembled Ag nanoparticles. We find that the thickness dependence of rear SiO2 layer (from 8 nm - 134 nm) on photocurrent shows an asymmetry for planar and scattering reflectors, moreover, the scattering reflectors perform much better than the planar reflectors under all tested SiO2 thicknesses. A maximum current enhancement (calculated from wavelength 900 nm to 1200 nm) of 12.1% is presented for planar reflector with 134 nm SiO2 film, and 18.4% for scattering reflector with the optimized 19 nm rear SiO2 film. Additionally, by adding a detached metal mirror, the maximum current enhancement from scattering reflector jumps to 27.0%. Effective optical path length Z is calculated to study the light trapping (optical properties) under various SiO2 thicknesses for both reflectors. Diffusion length L is calculated to track the electrical performance. It is shown that thicker SiO2 is of benefit for both optical and electrical properties when planar Al reflector is used. However, for scattering reflectors, thinner SiO2 is preferable for optical enhancement, but thicker SiO2 is desirable for electrical gain. 19 nm SiO2 is found to be the best choice for cells with scattering reflectors, considering both effects.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":"52 1","pages":"001172-001176"},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84896885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-06-03DOI: 10.1109/PVSC.2012.6318274
A. Boca, P. Blumenfeld, K. Crist, K. de Zetter, R. Mitchell, B. Richards, C. Sarver, P. Sharps, M. Stan, C. Tourino
The Solar Probe Plus (SPP) spacecraft will fly further into the Sun's corona than any previous mission, reaching a minimum perihelion at 9.5 solar radii from the center of the Sun. The solar arrays powering the spacecraft will operate under unusually high irradiances and temperatures. The array design, material choices, and necessary test facilities for SPP are therefore quite different from those used on traditional space panels. This paper gives an overview of the high-irradiance high-temperature vacuum (HIHT-Vac) reliability testing completed to date at Emcore on three small-scale coupons representing two competing SPP-array technologies. Both technologies successfully passed the HIHT-Vac test with no measurable performance, visual or mechanical degradation, reaching a key milestone in the development of the SPP array.
{"title":"High-irradiance high-temperature vacuum testing of the Solar Probe Plus array design","authors":"A. Boca, P. Blumenfeld, K. Crist, K. de Zetter, R. Mitchell, B. Richards, C. Sarver, P. Sharps, M. Stan, C. Tourino","doi":"10.1109/PVSC.2012.6318274","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6318274","url":null,"abstract":"The Solar Probe Plus (SPP) spacecraft will fly further into the Sun's corona than any previous mission, reaching a minimum perihelion at 9.5 solar radii from the center of the Sun. The solar arrays powering the spacecraft will operate under unusually high irradiances and temperatures. The array design, material choices, and necessary test facilities for SPP are therefore quite different from those used on traditional space panels. This paper gives an overview of the high-irradiance high-temperature vacuum (HIHT-Vac) reliability testing completed to date at Emcore on three small-scale coupons representing two competing SPP-array technologies. Both technologies successfully passed the HIHT-Vac test with no measurable performance, visual or mechanical degradation, reaching a key milestone in the development of the SPP array.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":"36 1","pages":"003269-003274"},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76662880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-06-03DOI: 10.1109/PVSC.2012.6317767
K. Yeung, M. Goorsky
The effect of offcut angle on the electrical conductivity of III-V multijunction solar devices is investigated using n-GaAs/n-GaAs direct-bonded structures. In the solar industry, misoriented substrates are commonly used in the growth of III-V epitaxial layers. In addition, wafer bonding has been proposed as a potential method of integrating lattice-mismatched materials to avoid the formation of threading dislocations. Our previously published papers showed that sulfur passivation reduces the density of surface charge states and improves the interface conductivity. However, the impact of the offcut angle on the electrical properties has not been explored. n-GaAs wafers miscut towards <;111>; A are chosen and compared to nominal on-axis (001) substrates. The surfaces are treated with either an oxide etch or additional soak in aqueous (NH4)2S. Off-axis wafers are bonded face-to-face in various orientations and then annealed at 400 °C for two hours. It is observed that the electrical conductivity improves considerably with a short rapid thermal processing at 600 °C. However, the out-of-plane relative surface misorientations between the tilted (001) planes greater than 4° exhibit increasingly non-ohmic behavior. A theoretical model that describes the electron tunneling across a grain boundary between semiconductor bicrystals is used to represent the bonded interface and estimate the barrier conduction height. Fitting the zero-bias conductance over a range of temperatures reveals a 0.4 eV increase in barrier height for 12° misoriented sulfur-passivated bonded pairs. Accordingly, the interface resistance at room temperature rises from 0.01 Ω·cm2 to 3.4 Ω·cm2. These results demonstrate that the out-of-plane relative surface misorientation is the critical parameter to be monitored in order to achieve superior electrical conductivity in direct-bonded multijunction solar applications.
{"title":"The effect of offcut angle on electrical conductivity of wafer-bonded n-GaAs/n-GaAs structures for wafer-bonded tandem solar cells","authors":"K. Yeung, M. Goorsky","doi":"10.1109/PVSC.2012.6317767","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6317767","url":null,"abstract":"The effect of offcut angle on the electrical conductivity of III-V multijunction solar devices is investigated using n-GaAs/n-GaAs direct-bonded structures. In the solar industry, misoriented substrates are commonly used in the growth of III-V epitaxial layers. In addition, wafer bonding has been proposed as a potential method of integrating lattice-mismatched materials to avoid the formation of threading dislocations. Our previously published papers showed that sulfur passivation reduces the density of surface charge states and improves the interface conductivity. However, the impact of the offcut angle on the electrical properties has not been explored. n-GaAs wafers miscut towards <;111>; A are chosen and compared to nominal on-axis (001) substrates. The surfaces are treated with either an oxide etch or additional soak in aqueous (NH4)2S. Off-axis wafers are bonded face-to-face in various orientations and then annealed at 400 °C for two hours. It is observed that the electrical conductivity improves considerably with a short rapid thermal processing at 600 °C. However, the out-of-plane relative surface misorientations between the tilted (001) planes greater than 4° exhibit increasingly non-ohmic behavior. A theoretical model that describes the electron tunneling across a grain boundary between semiconductor bicrystals is used to represent the bonded interface and estimate the barrier conduction height. Fitting the zero-bias conductance over a range of temperatures reveals a 0.4 eV increase in barrier height for 12° misoriented sulfur-passivated bonded pairs. Accordingly, the interface resistance at room temperature rises from 0.01 Ω·cm2 to 3.4 Ω·cm2. These results demonstrate that the out-of-plane relative surface misorientation is the critical parameter to be monitored in order to achieve superior electrical conductivity in direct-bonded multijunction solar applications.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":"5 1","pages":"000982-000987"},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76994338","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-06-03DOI: 10.1109/PVSC.2012.6317974
Yunpeng Wang, H. Sodabanlu, Shaojun Ma, H. Fujii, K. Watanabe, M. Sugiyama, Y. Nakano
In the report, we propose a multiple stepped superlattice (MS-SL) structure, in which GaAs stepped-potential layers are sandwiched between strain-balanced InGaAs wells and GaAsP barriers, for photovoltaic application. Comparison between the normal SL cell and MS-SL cell indicate that the step design in MS-SL cell enhanced sunband absorption to the host bulk material, while reduced overall recombination loss, exhibited a surprising advantage over SL cell in conversion efficiency. According to experimental results, discussions have been made on the competition process between carrier recombinations and carrier escape kinetics from the wells.
{"title":"A multi-step superlattice solar cell with enhanced subband absorption and open circuit voltage","authors":"Yunpeng Wang, H. Sodabanlu, Shaojun Ma, H. Fujii, K. Watanabe, M. Sugiyama, Y. Nakano","doi":"10.1109/PVSC.2012.6317974","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6317974","url":null,"abstract":"In the report, we propose a multiple stepped superlattice (MS-SL) structure, in which GaAs stepped-potential layers are sandwiched between strain-balanced InGaAs wells and GaAsP barriers, for photovoltaic application. Comparison between the normal SL cell and MS-SL cell indicate that the step design in MS-SL cell enhanced sunband absorption to the host bulk material, while reduced overall recombination loss, exhibited a surprising advantage over SL cell in conversion efficiency. According to experimental results, discussions have been made on the competition process between carrier recombinations and carrier escape kinetics from the wells.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":"18 1","pages":"001940-001943"},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77148450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-06-03DOI: 10.1109/PVSC.2012.6318266
R. Einhaus, J. Kraiem, J. Degoulange, O. Nichiporuk, M. Forster, P. Papet, Y. Andrault, D. Grosset-Bourbange, F. Cocco
Highly purified n-type UMG (“Upgraded Metallurgical”) Silicon is a material with a strong potential for high efficiency low cost solar cells. Compared to p-type Silicon, n-type Silicon is in general less susceptible to lifetime degradation due to residual metal impurities or to light induced degradation due to the Boron-Oxygen complex. In this work a 15kg 6 inch mono-c Cz Silicon ingot has been grown from 100% highly purified UMG Silicon obtained with the PHOTOSIL process. In this feedstock the Boron and Phosphorus concentrations measured by GDMS were found to be 0.3 ppmw and 2 ppmw, respectively. The resulting ingot is n-type, fully mono c1 rystalline and has a resistivity range from 0.2 to 1 ohm.cm. Other impurities, especially metals, were not detectable with the analysis techniques applied (GDMS, ICP-OES). The ingot was cut into 125×125 mm2 pseudo square wafers of 180 micron thickness. A first series of solar cells were processed on these wafers using an industrial hetero-junction process by Roth & Rau. The best solar cell from a batch of 14 had an energy conversion efficiency of 19.0% (compared to an average: 18.6%) under standard testing conditions with a very high Voc of 725mV.. An independent confirmation of these results is pending.
{"title":"19% efficiency heterojunction solar cells on Cz wafers from non-blended Upgraded Metallurgical Silicon","authors":"R. Einhaus, J. Kraiem, J. Degoulange, O. Nichiporuk, M. Forster, P. Papet, Y. Andrault, D. Grosset-Bourbange, F. Cocco","doi":"10.1109/PVSC.2012.6318266","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6318266","url":null,"abstract":"Highly purified n-type UMG (“Upgraded Metallurgical”) Silicon is a material with a strong potential for high efficiency low cost solar cells. Compared to p-type Silicon, n-type Silicon is in general less susceptible to lifetime degradation due to residual metal impurities or to light induced degradation due to the Boron-Oxygen complex. In this work a 15kg 6 inch mono-c Cz Silicon ingot has been grown from 100% highly purified UMG Silicon obtained with the PHOTOSIL process. In this feedstock the Boron and Phosphorus concentrations measured by GDMS were found to be 0.3 ppmw and 2 ppmw, respectively. The resulting ingot is n-type, fully mono c1 rystalline and has a resistivity range from 0.2 to 1 ohm.cm. Other impurities, especially metals, were not detectable with the analysis techniques applied (GDMS, ICP-OES). The ingot was cut into 125×125 mm2 pseudo square wafers of 180 micron thickness. A first series of solar cells were processed on these wafers using an industrial hetero-junction process by Roth & Rau. The best solar cell from a batch of 14 had an energy conversion efficiency of 19.0% (compared to an average: 18.6%) under standard testing conditions with a very high Voc of 725mV.. An independent confirmation of these results is pending.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":"37 1","pages":"003234-003237"},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81017436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-06-03DOI: 10.1109/PVSC.2012.6317820
M. Ko, C. Baek, T. Rim, S. Park, Y. Jeong
We propose an asymmetric structure using simulation to improve the electrical characteristics of the solar cell. This structure is designed by shrinking the bottom core diameter in radial structure. It causes the total reflection of the incident light in the outer wall and the light concentration in the bottom core. Consequently, an asymmetric solar cell (ASC) shows the increase in current density and cell efficiency (CE), which is 10 % higher than those of a symmetric solar cell (SSC). By increasing doping concentration of the shell and applying light trapping techniques i.e. anti-reflective coating and back-surface-field, the ASC showed high CE compared with the SSC. This novel structure offers an opportunity for effectively improving the CE.
{"title":"Si thin film solar cell with asymmetric p-n junction","authors":"M. Ko, C. Baek, T. Rim, S. Park, Y. Jeong","doi":"10.1109/PVSC.2012.6317820","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6317820","url":null,"abstract":"We propose an asymmetric structure using simulation to improve the electrical characteristics of the solar cell. This structure is designed by shrinking the bottom core diameter in radial structure. It causes the total reflection of the incident light in the outer wall and the light concentration in the bottom core. Consequently, an asymmetric solar cell (ASC) shows the increase in current density and cell efficiency (CE), which is 10 % higher than those of a symmetric solar cell (SSC). By increasing doping concentration of the shell and applying light trapping techniques i.e. anti-reflective coating and back-surface-field, the ASC showed high CE compared with the SSC. This novel structure offers an opportunity for effectively improving the CE.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":"29 1","pages":"001212-001216"},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82044931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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