Pub Date : 2013-11-07DOI: 10.1109/PVSC-VOL2.2013.6656713
D. Sarkar, E. Onyegam, S. Saha, L. Mathew, R. Rao, M. Hilali, R. S. Smith, Dewei Xu, D. Jawarani, R. Garcia, R. Stout, A. Gurmu, M. Ainom, J. Fossum, S. Banerjee
For the first time, a remote plasma chemical vapor deposition (RPCVD) based c-Si/a-Si heterojunction solar cell process was developed on thin crystalline silicon semiconductor-on-metal (SOM) substrate. In RPCVD systems, deposition temperature, deposition rate, and the distance of the sample from the plasma source can be varied to minimize the surface damage and enhance passivation quality. A silicon heterojunction (HJ) cell without intrinsic a-Si layer passivation was fabricated on an exfoliated ∼25µm c-Si SOM foil, with an efficiency of 13.4% and open-circuit voltage of 645mV. Losses in these devices were analyzed by numerical simulations and optimum device structure was designed and performance predicted.
{"title":"Remote plasma chemical vapor deposition for high-efficiency ultra-thin ∼25-microns crystalline Si solar cells","authors":"D. Sarkar, E. Onyegam, S. Saha, L. Mathew, R. Rao, M. Hilali, R. S. Smith, Dewei Xu, D. Jawarani, R. Garcia, R. Stout, A. Gurmu, M. Ainom, J. Fossum, S. Banerjee","doi":"10.1109/PVSC-VOL2.2013.6656713","DOIUrl":"https://doi.org/10.1109/PVSC-VOL2.2013.6656713","url":null,"abstract":"For the first time, a remote plasma chemical vapor deposition (RPCVD) based c-Si/a-Si heterojunction solar cell process was developed on thin crystalline silicon semiconductor-on-metal (SOM) substrate. In RPCVD systems, deposition temperature, deposition rate, and the distance of the sample from the plasma source can be varied to minimize the surface damage and enhance passivation quality. A silicon heterojunction (HJ) cell without intrinsic a-Si layer passivation was fabricated on an exfoliated ∼25µm c-Si SOM foil, with an efficiency of 13.4% and open-circuit voltage of 645mV. Losses in these devices were analyzed by numerical simulations and optimum device structure was designed and performance predicted.","PeriodicalId":6420,"journal":{"name":"2012 IEEE 38th Photovoltaic Specialists Conference (PVSC) PART 2","volume":"46 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2013-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80497884","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 : 2013-11-07DOI: 10.1109/PVSC-VOL2.2012.6656703
M. Theelen, M. Tomassini, N. Barreau, H. Steijvers, A. Branca, S. Harel, Z. Vroon, M. Zeman
Molybdenum (Mo) degrades under the influence of damp heat, thereby reducing the output of CIGS PV. In this study, Mo layers were deposited on a glass substrate by magnetron sputtering, thereby varying the deposition pressure and the addition of selenium. These samples were thoroughly analysed and degraded at 60oC/60% relative humidity (RH) and 85°C /85% RH.
{"title":"The impact of selenisation on damp heat degradation of the CIGS back contact molybdenum","authors":"M. Theelen, M. Tomassini, N. Barreau, H. Steijvers, A. Branca, S. Harel, Z. Vroon, M. Zeman","doi":"10.1109/PVSC-VOL2.2012.6656703","DOIUrl":"https://doi.org/10.1109/PVSC-VOL2.2012.6656703","url":null,"abstract":"Molybdenum (Mo) degrades under the influence of damp heat, thereby reducing the output of CIGS PV. In this study, Mo layers were deposited on a glass substrate by magnetron sputtering, thereby varying the deposition pressure and the addition of selenium. These samples were thoroughly analysed and degraded at 60oC/60% relative humidity (RH) and 85°C /85% RH.","PeriodicalId":6420,"journal":{"name":"2012 IEEE 38th Photovoltaic Specialists Conference (PVSC) PART 2","volume":"21 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2013-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79061502","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}
Jay Johnson, B. Schenkman, A. Ellis, J. Quiroz, C. Lenox
The 1.2-MW La Ola photovoltaic (PV) power plant in Lanai, Hawaii, has been in operation since December 2009. The host system is a small island microgrid with peak load of 5 MW. Simulations conducted as part of the interconnection study concluded that unmitigated PV output ramps had the potential to negatively affect system frequency. Based on that study, the PV system was initially allowed to operate with output limited to 50% of nameplate power capacity to reduce the potential for frequency instability due to PV variability. Based on the analysis of historical voltage, frequency, and power output data at 50% output level, the PV system has not significantly affected grid performance. However, it should be noted that the impact of PV variability on active and reactive power output of the nearby diesel generators was not evaluated.
{"title":"Initial operating experience of the 1.2-MW La Ola photovoltaic system","authors":"Jay Johnson, B. Schenkman, A. Ellis, J. Quiroz, C. Lenox","doi":"10.2172/1031297","DOIUrl":"https://doi.org/10.2172/1031297","url":null,"abstract":"The 1.2-MW La Ola photovoltaic (PV) power plant in Lanai, Hawaii, has been in operation since December 2009. The host system is a small island microgrid with peak load of 5 MW. Simulations conducted as part of the interconnection study concluded that unmitigated PV output ramps had the potential to negatively affect system frequency. Based on that study, the PV system was initially allowed to operate with output limited to 50% of nameplate power capacity to reduce the potential for frequency instability due to PV variability. Based on the analysis of historical voltage, frequency, and power output data at 50% output level, the PV system has not significantly affected grid performance. However, it should be noted that the impact of PV variability on active and reactive power output of the nearby diesel generators was not evaluated.","PeriodicalId":6420,"journal":{"name":"2012 IEEE 38th Photovoltaic Specialists Conference (PVSC) PART 2","volume":"9 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2013-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74524766","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 : 2013-11-07DOI: 10.1109/PVSC-VOL2.2013.6656702
A. Bhatia, H. Meadows, M. C. Hymas, E. Smith, P. Dale, M. Scarpulla
Pulsed-laser annealing (PLA) of Cu(In,Ga)Se2 thin films has been shown to improve their optoelectronic properties. Here we investigate the effects of ns PLA on the identity of traps in CuInSe2 films prepared by electrodeposition followed by furnace annealing with Se. Raman spectroscopy indicates a decrease in width of the A1 phonon peak and relaxation of compressive strain after PLA. Current-voltage measurements indicate improvement in ideality factor of heterojunction diode cells built from laser irradiated films. Defect spectroscopy on Schottky diode and complete solar cell reveal similar defect level for EDA_ref sample present at ≈ 200 meV. However for the sample processed at 30 mJ/cm2 we find a deep trap at ≈ 300 meV in case of Schottky diodes, whereas complete solar cells show a trap at ≈ 60 meV.
{"title":"Study of point defects in ns pulsed-laser annealed CuInSe2 thin films","authors":"A. Bhatia, H. Meadows, M. C. Hymas, E. Smith, P. Dale, M. Scarpulla","doi":"10.1109/PVSC-VOL2.2013.6656702","DOIUrl":"https://doi.org/10.1109/PVSC-VOL2.2013.6656702","url":null,"abstract":"Pulsed-laser annealing (PLA) of Cu(In,Ga)Se2 thin films has been shown to improve their optoelectronic properties. Here we investigate the effects of ns PLA on the identity of traps in CuInSe2 films prepared by electrodeposition followed by furnace annealing with Se. Raman spectroscopy indicates a decrease in width of the A1 phonon peak and relaxation of compressive strain after PLA. Current-voltage measurements indicate improvement in ideality factor of heterojunction diode cells built from laser irradiated films. Defect spectroscopy on Schottky diode and complete solar cell reveal similar defect level for EDA_ref sample present at ≈ 200 meV. However for the sample processed at 30 mJ/cm2 we find a deep trap at ≈ 300 meV in case of Schottky diodes, whereas complete solar cells show a trap at ≈ 60 meV.","PeriodicalId":6420,"journal":{"name":"2012 IEEE 38th Photovoltaic Specialists Conference (PVSC) PART 2","volume":"33 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2013-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81732903","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 : 2013-01-01DOI: 10.1109/pvsc-vol2.2012.6656724
D. Aiken, E. Dons, Sang-Soo Je, N. Miller, F. Newman, P. Patel, J. Spann
A commercial lattice-matched InGaP/InGaAs/Ge solar cell has reached an average efficiency of 40% at 500 kW/m2. The design changes that lead to this result are discussed. These data are complemented with a presentation of the latest new solar cell development results from the laboratory. Inverted metamorphic multijunction solar cells have been prototyped with 42.4% efficiency at 325 suns for concentrator applications and 33.6% efficiency at 1 sun AM0 for space applications. Six subcell devices are now under development. These results are used, along with other experimental data and other industrial constraints, as input to a computer model to predict what practical efficiency might be achievable with this device approach. The computer model suggests that 45% and 50% efficiencies are technologically feasible with a three-junction and five-junction device, respectively, at an irradiance of 500 kW/m2 and 25 °C using known materials, device architectures, and manufacturing methods.
{"title":"Lattice-matched solar cells with 40% average efficiency in pilot production and a roadmap to 50%","authors":"D. Aiken, E. Dons, Sang-Soo Je, N. Miller, F. Newman, P. Patel, J. Spann","doi":"10.1109/pvsc-vol2.2012.6656724","DOIUrl":"https://doi.org/10.1109/pvsc-vol2.2012.6656724","url":null,"abstract":"A commercial lattice-matched InGaP/InGaAs/Ge solar cell has reached an average efficiency of 40% at 500 kW/m2. The design changes that lead to this result are discussed. These data are complemented with a presentation of the latest new solar cell development results from the laboratory. Inverted metamorphic multijunction solar cells have been prototyped with 42.4% efficiency at 325 suns for concentrator applications and 33.6% efficiency at 1 sun AM0 for space applications. Six subcell devices are now under development. These results are used, along with other experimental data and other industrial constraints, as input to a computer model to predict what practical efficiency might be achievable with this device approach. The computer model suggests that 45% and 50% efficiencies are technologically feasible with a three-junction and five-junction device, respectively, at an irradiance of 500 kW/m2 and 25 °C using known materials, device architectures, and manufacturing methods.","PeriodicalId":6420,"journal":{"name":"2012 IEEE 38th Photovoltaic Specialists Conference (PVSC) PART 2","volume":"42 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2013-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76499838","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 : 2013-01-01DOI: 10.1109/pvsc-vol2.2012.6656736
D. Attygalle, V. Ranjan, P. Aryal, P. Pradhan, S. Marsillac, N. Podraza, R. Collins
Real-time spectroscopic ellipsometry (RTSE) has been applied for in situ monitoring and control of thin-film copper-indium-gallium-diselenide, i.e., Cu(In1−xGax)Se2 (CIGS), deposition by high vacuum coevaporation in the three-stage process used for efficient photovoltaic devices. Initial studies have been performed on a ∼0.7-µm CIGS layer deposited on crystal silicon to minimize surface roughness and to develop an accurate structural/ optical model of the Cu-poor-to-Cu-rich and Cu-rich-to-Cu-poor transitions that define the ends of the second (II) and third (III) stages of growth, respectively.With a better understanding of the surface achieved through this model, correlations can be made between the surface state and the unprocessed RTSE data {ψ(t), Δ(t)}. During deposition in the solar cell configuration with 2- µm-thick CIGS on a Mo-coated glass substrate, indications of the Cu poor-to-rich and Cu rich-to-poor transitions appear clearly in {ψ(t), Δ(t)}, enabling direct control of stage II and III transitions. The transition times deduced optically are in good agreement with those identified from the film/substrate emissivity by tracking the substrate heater power. It is clear, however, that RTSE can provide higher sensitivity to these transitions and is, therefore, suitable for improved control of three-stage CIGS deposition.
{"title":"Optical monitoring and control of three-stage coevaporated Cu(In1−xGax)Se2 by real-time spectroscopic ellipsometry","authors":"D. Attygalle, V. Ranjan, P. Aryal, P. Pradhan, S. Marsillac, N. Podraza, R. Collins","doi":"10.1109/pvsc-vol2.2012.6656736","DOIUrl":"https://doi.org/10.1109/pvsc-vol2.2012.6656736","url":null,"abstract":"Real-time spectroscopic ellipsometry (RTSE) has been applied for in situ monitoring and control of thin-film copper-indium-gallium-diselenide, i.e., Cu(In1−xGax)Se2 (CIGS), deposition by high vacuum coevaporation in the three-stage process used for efficient photovoltaic devices. Initial studies have been performed on a ∼0.7-µm CIGS layer deposited on crystal silicon to minimize surface roughness and to develop an accurate structural/ optical model of the Cu-poor-to-Cu-rich and Cu-rich-to-Cu-poor transitions that define the ends of the second (II) and third (III) stages of growth, respectively.With a better understanding of the surface achieved through this model, correlations can be made between the surface state and the unprocessed RTSE data {ψ(t), Δ(t)}. During deposition in the solar cell configuration with 2- µm-thick CIGS on a Mo-coated glass substrate, indications of the Cu poor-to-rich and Cu rich-to-poor transitions appear clearly in {ψ(t), Δ(t)}, enabling direct control of stage II and III transitions. The transition times deduced optically are in good agreement with those identified from the film/substrate emissivity by tracking the substrate heater power. It is clear, however, that RTSE can provide higher sensitivity to these transitions and is, therefore, suitable for improved control of three-stage CIGS deposition.","PeriodicalId":6420,"journal":{"name":"2012 IEEE 38th Photovoltaic Specialists Conference (PVSC) PART 2","volume":"11 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2013-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72832193","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 : 2013-01-01DOI: 10.1109/pvsc-vol2.2012.6656704
Dae‐Hyung Cho, Yong‐Duck Chung, Kyu‐Seok Lee, Ju-hee Kim, Soojeong Park, Jeha Kim
We report on the effect of Na incorporation into Cu(In,Ga)Se2 (CIGS) for thin-film solar cells. Na ions were supplied by NaF films with different thicknesses, while those from the soda-lime glass substrate were controlled by a presence or an absence of a SiOx barrier. Gradually increasing a Na content in CIGS was found in the structures of CIGS/Mo/SiOx/SLG, CIGS/Mo/SLG, CIGS/5 nm-NaF/Mo/SiOx/SLG, CIGS/5 nm-NaF/Mo/SLG, CIGS/15 nm-NaF/Mo/SiOx/SLG, and CIGS/15 nm-NaF/Mo/SLG. With increasing the Na content, the CIGS (112) preferential orientation growth became dominant, while the (220/204) one was nearly constant. The grain size decreased with increasing the Na content. The cell efficiency (η) increased for relatively low Na content however the thick NaF led to a degradation of η because of poor adhesion between the CIGS and the Mo. The sample with the CIGS/5 nm-NaF/Mo/SiOx/SLG structure achieved the comparable (112)/(220/204) peak ratios, grain sizes, as well as the cell performances to a CIGS/Mo/SLG structure that contains the same Na content in the CIGS.
{"title":"Control of Na diffusion from soda-lime glass and NaF film into Cu(In,Ga)Se2 for thin-film solar cells","authors":"Dae‐Hyung Cho, Yong‐Duck Chung, Kyu‐Seok Lee, Ju-hee Kim, Soojeong Park, Jeha Kim","doi":"10.1109/pvsc-vol2.2012.6656704","DOIUrl":"https://doi.org/10.1109/pvsc-vol2.2012.6656704","url":null,"abstract":"We report on the effect of Na incorporation into Cu(In,Ga)Se2 (CIGS) for thin-film solar cells. Na ions were supplied by NaF films with different thicknesses, while those from the soda-lime glass substrate were controlled by a presence or an absence of a SiOx barrier. Gradually increasing a Na content in CIGS was found in the structures of CIGS/Mo/SiOx/SLG, CIGS/Mo/SLG, CIGS/5 nm-NaF/Mo/SiOx/SLG, CIGS/5 nm-NaF/Mo/SLG, CIGS/15 nm-NaF/Mo/SiOx/SLG, and CIGS/15 nm-NaF/Mo/SLG. With increasing the Na content, the CIGS (112) preferential orientation growth became dominant, while the (220/204) one was nearly constant. The grain size decreased with increasing the Na content. The cell efficiency (η) increased for relatively low Na content however the thick NaF led to a degradation of η because of poor adhesion between the CIGS and the Mo. The sample with the CIGS/5 nm-NaF/Mo/SiOx/SLG structure achieved the comparable (112)/(220/204) peak ratios, grain sizes, as well as the cell performances to a CIGS/Mo/SLG structure that contains the same Na content in the CIGS.","PeriodicalId":6420,"journal":{"name":"2012 IEEE 38th Photovoltaic Specialists Conference (PVSC) PART 2","volume":"22 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2013-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82145593","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 : 2013-01-01DOI: 10.1109/pvsc-vol2.2012.6656787
Y. Tauchi, Kihwan Kim, Hyeonwook Park, W. Shafarman
In this paper, the effects of Ag-alloying in the selenization of metal precursors to form (AgCu) (InGa)Se2 are investigated. Metal precursors with different structures were prepared by sputtering from Cu0.77Ga0.23, Ag, and In targets. The phases and the composition of the precursor films were evaluated by X-ray diffraction, scanning electron microscopy (SEM), and energy dispersive X-ray spectrometry. The addition of a Ag layer between the Mo and Cu-Ga-In layers resulted in much less islanding of In-rich phases than typically observed in sputtered Cu-Ga-In films. Selenization at 475 °C of Ag-containing precursors resulted in better adhesion than precursors without Ag. After the selenization reaction, Ag and Cu were uniformly distributed through the film, although Ga remained near the back of the film, as was observed in precursors without Ag. A (AgCu)(InGa)Se2 -based solar cell with 13.9% efficiency was demonstrated.
{"title":"Characterization of (AgCu)(InGa)Se2 absorber layer fabricated by a selenization process from metal precursor","authors":"Y. Tauchi, Kihwan Kim, Hyeonwook Park, W. Shafarman","doi":"10.1109/pvsc-vol2.2012.6656787","DOIUrl":"https://doi.org/10.1109/pvsc-vol2.2012.6656787","url":null,"abstract":"In this paper, the effects of Ag-alloying in the selenization of metal precursors to form (AgCu) (InGa)Se2 are investigated. Metal precursors with different structures were prepared by sputtering from Cu0.77Ga0.23, Ag, and In targets. The phases and the composition of the precursor films were evaluated by X-ray diffraction, scanning electron microscopy (SEM), and energy dispersive X-ray spectrometry. The addition of a Ag layer between the Mo and Cu-Ga-In layers resulted in much less islanding of In-rich phases than typically observed in sputtered Cu-Ga-In films. Selenization at 475 °C of Ag-containing precursors resulted in better adhesion than precursors without Ag. After the selenization reaction, Ag and Cu were uniformly distributed through the film, although Ga remained near the back of the film, as was observed in precursors without Ag. A (AgCu)(InGa)Se2 -based solar cell with 13.9% efficiency was demonstrated.","PeriodicalId":6420,"journal":{"name":"2012 IEEE 38th Photovoltaic Specialists Conference (PVSC) PART 2","volume":"2 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2013-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81320875","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 : 2013-01-01DOI: 10.1109/pvsc-vol2.2012.6656751
Kihwan Kim, Hyeonwook Park, W. Kim, G. Hanket, W. Shafarman
Cu(In,Ga)(Se,S)2 (CIGSS) absorbers with thicknesses from 1.9 to 0.25 µm have been grown using a three-step selenization/Ar-anneal/sulfization reaction ofCu-In-Ga metal precursors. Material characterization revealed changes in orientation, apparent grain size, and formation of voids at the Mo/CIGSS interface with reduced thickness. Even with absorber thickness decreased to 0.25 µm and lateral compositional nonuniformity, VOC and fill factor were nearly sustained, while JSC decreased due to incomplete absorption. With the 0.25-µm-thick absorber layer, an efficiency of 9.1% (without AR coating) with VOC = 612 mV, JSC = 21.0 mA/cm2, and FF = 71.1% was obtained.
{"title":"Effect of reduced Cu(InGa)(SeS)2 thickness using three-step H2Se/Ar/H2S reaction of Cu-In-Ga metal precursor","authors":"Kihwan Kim, Hyeonwook Park, W. Kim, G. Hanket, W. Shafarman","doi":"10.1109/pvsc-vol2.2012.6656751","DOIUrl":"https://doi.org/10.1109/pvsc-vol2.2012.6656751","url":null,"abstract":"Cu(In,Ga)(Se,S)<inf>2</inf> (CIGSS) absorbers with thicknesses from 1.9 to 0.25 µm have been grown using a three-step selenization/Ar-anneal/sulfization reaction ofCu-In-Ga metal precursors. Material characterization revealed changes in orientation, apparent grain size, and formation of voids at the Mo/CIGSS interface with reduced thickness. Even with absorber thickness decreased to 0.25 µm and lateral compositional nonuniformity, V<inf>OC</inf> and fill factor were nearly sustained, while J<inf>SC</inf> decreased due to incomplete absorption. With the 0.25-µm-thick absorber layer, an efficiency of 9.1% (without AR coating) with V<inf>OC</inf> = 612 mV, J<inf>SC</inf> = 21.0 mA/cm<sup>2</sup>, and FF = 71.1% was obtained.","PeriodicalId":6420,"journal":{"name":"2012 IEEE 38th Photovoltaic Specialists Conference (PVSC) PART 2","volume":"1 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2013-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90693714","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 : 2013-01-01DOI: 10.1109/pvsc-vol2.2013.6656718
M. Reno, J. Stein
High frequency irradiance variability measured on the ground is caused by the formation, dissipation, and passage of clouds in the sky. Variability and ramp rates of PV systems are increasingly important to understand and model for grid stability as PV penetration levels rise. Using satellite imagery to identify cloud types and patterns can predict irradiance variability in areas lacking sensors. With satellite imagery covering the entire U.S., this allows for more accurate integration planning and power flow modelling over wide areas. Satellite imagery from southern Nevada was analyzed at 15 minute intervals over a year. Methods for image stabilization, cloud detection, and textural classification of clouds were developed and tested. High Performance Computing parallel processing algorithms were also investigated and tested. Artificial Neural Networks using imagery as inputs were trained on ground-based measurements of irradiance to model the variability and were tested to show some promise as a means for predicting irradiance variability. Artificial Neural Networks, cloud texture analysis, and cloud type categorization can be used to model the irradiance and variability for a location at a one minute resolution without needing many ground based irradiance sensors.
{"title":"PV output variability modeling using satellite imagery and neural networks","authors":"M. Reno, J. Stein","doi":"10.1109/pvsc-vol2.2013.6656718","DOIUrl":"https://doi.org/10.1109/pvsc-vol2.2013.6656718","url":null,"abstract":"High frequency irradiance variability measured on the ground is caused by the formation, dissipation, and passage of clouds in the sky. Variability and ramp rates of PV systems are increasingly important to understand and model for grid stability as PV penetration levels rise. Using satellite imagery to identify cloud types and patterns can predict irradiance variability in areas lacking sensors. With satellite imagery covering the entire U.S., this allows for more accurate integration planning and power flow modelling over wide areas. Satellite imagery from southern Nevada was analyzed at 15 minute intervals over a year. Methods for image stabilization, cloud detection, and textural classification of clouds were developed and tested. High Performance Computing parallel processing algorithms were also investigated and tested. Artificial Neural Networks using imagery as inputs were trained on ground-based measurements of irradiance to model the variability and were tested to show some promise as a means for predicting irradiance variability. Artificial Neural Networks, cloud texture analysis, and cloud type categorization can be used to model the irradiance and variability for a location at a one minute resolution without needing many ground based irradiance sensors.","PeriodicalId":6420,"journal":{"name":"2012 IEEE 38th Photovoltaic Specialists Conference (PVSC) PART 2","volume":"17 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2013-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85103057","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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