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Stefan Rein - One of the best experts on this subject based on the ideXlab platform.
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Short-Circuit Current Density Imaging Methods for Silicon Solar Cells
Energy Procedia, 2015Co-Authors: Fabian Fertig, Otwin Breitenstein, M. C. Schubert, Ino Geisemeyer, Hannes Höffler, Milan Padilla, Stefan ReinAbstract:Abstract Recently, several novel methods have been proposed to image Short-Circuit Current Density j sc based on diverse physical principles. This work compares these methods and points out physical limitations, advantages and drawbacks of each approach. One method based on photoluminescence (PL) imaging and two methods based on dark and illuminated lock-in thermography (DLIT / ILIT) are discussed. As a versatile reference technique for j sc mapping, spectrally-resolved light-beam induced Current (SR-LBIC) is applied. Experimental results for crystalline silicon solar cells with varying substrate properties, rear-side passivation schemes and process-induced defects are presented. Investigated parameters are quantitative accuracy of local j sc , spatial resolution, measurement time, spectral excitation dependency and calibration. Furthermore, robustness towards locally increased series resistance R s and injection-dependent recombination is discussed along with proneness to artefacts due to local shunts, spatially varying optics and photogeneration, and fitting algorithm artefacts.
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Short-Circuit Current Density Imaging Methods for Silicon Solar Cells
Energy Procedia, 2015Co-Authors: Fabian Fertig, Mario Padilla, H. H?ffler, Otwin Breitenstein, M. C. Schubert, Ino Geisemeyer, Stefan ReinAbstract:? 2015 The Authors.Recently, several novel methods have been proposed to image Short-Circuit Current Density jsc based on diverse physical principles. This work compares these methods and points out physical limitations, advantages and drawbacks of each approach. One method based on photoluminescence (PL) imaging and two methods based on dark and illuminated lock-in thermography (DLIT / ILIT) are discussed. As a versatile reference technique for jsc mapping, spectrally-resolved light-beam induced Current (SR-LBIC) is applied. Experimental results for crystalline silicon solar cells with varying substrate properties, rear-side passivation schemes and process-induced defects are presented. Investigated parameters are quantitative accuracy of local jsc, spatial resolution, measurement time, spectral excitation dependency and calibration. Furthermore, robustness towards locally increased series resistance Rs and injection-dependent recombination is discussed along with proneness to artefacts due to local shunts, spatially varying optics and photogeneration, and fitting algorithm artefacts.
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Short-Circuit Current Density imaging of crystalline silicon solar cells via lock-in thermography: Robustness and simplifications
Journal of Applied Physics, 2014Co-Authors: Fabian Fertig, Johannes Greulich, Stefan ReinAbstract:Spatially resolved determination of solar cell parameters is beneficial for loss analysis and optimization of conversion efficiency. One key parameter that has been challenging to access by an imaging technique on solar cell level is Short-Circuit Current Density. This work discusses the robustness of a recently suggested approach to determine Short-Circuit Current Density spatially resolved based on a series of lock-in thermography images and options for a simplified image acquisition procedure. For an accurate result, one or two emissivity-corrected illuminated lock-in thermography images and one dark lock-in thermography image have to be recorded. The dark lock-in thermography image can be omitted if local shunts are negligible. Furthermore, it is shown that omitting the correction of lock-in thermography images for local emissivity variations only leads to minor distortions for standard silicon solar cells. Hence, adequate acquisition of one image only is sufficient to generate a meaningful map of Short-Circuit Current Density. Beyond that, this work illustrates the underlying physics of the recently proposed method and demonstrates its robustness concerning varying excitation conditions and locally increased series resistance. Experimentally gained Short-Circuit Current Density images are validated for monochromatic illumination in comparison to the reference method of light-beam induced Current.
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Spatially resolved determination of the Short-Circuit Current Density of silicon solar cells via lock-in thermography
Applied Physics Letters, 2014Co-Authors: Fabian Fertig, Johannes Greulich, Stefan ReinAbstract:We present a spatially resolved method to determine the Short-Circuit Current Density of crystalline silicon solar cells by means of lock-in thermography. The method utilizes the property of crystalline silicon solar cells that the Short-Circuit Current does not differ significantly from the illuminated Current under moderate reverse bias. Since lock-in thermography images locally dissipated power Density, this information is exploited to extract values of spatially resolved Current Density under Short-Circuit conditions. In order to obtain an accurate result, one or two illuminated lock-in thermography images and one dark lock-in thermography image need to be recorded. The method can be simplified in a way that only one image is required to generate a meaningful Short-Circuit Current Density map. The proposed method is theoretically motivated, and experimentally validated for monochromatic illumination in comparison to the reference method of light-beam induced Current. © 2014 AIP Publishing LLC.
Bryce S. Richards - One of the best experts on this subject based on the ideXlab platform.
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Increased Short-Circuit Current Density of production line CdTe mini-module through luminescent down-shifting
Solar Energy Materials and Solar Cells, 2012Co-Authors: David Ross, Jochen Fritsche, Efthymios Klampaftis, Michael Bauer, Bryce S. RichardsAbstract:Abstract The application of luminescent down-shifting (LDS) has been shown to improve the short wavelength response of a variety of different photovoltaic devices. Cadmium sulphide/cadmium telluride (CdS/CdTe) heterojunction devices possess a great potential for improvement via LDS due to the parasitic absorption of blue light by the CdS buffer layer. This work is the first to investigate LDS applied to mini-modules (72 cm2 active area) cut from full-size CdTe modules from a production line. The addition of LDS layers containing Lumogen Yellow 083 and Violet 570 dyes was demonstrated to increase the short circuit Current Density (JSC) of the mini-module by up to 9% relative. It was shown that the addition of the Yellow 083 dye alone more than doubles the short wavelength (300–500 nm) response of CdTe mini-modules. External quantum efficiency measurements are presented that clearly identified the wavelength range of photoCurrent enhancement, while increased efficiency was confirmed with Current–voltage (I–V) measurements.
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Increased Short-Circuit Current Density of production line CdTe mini-module through luminescent down-shifting
Solar Energy Materials and Solar Cells, 2012Co-Authors: David Ross, Jochen Fritsche, Efthymios Klampaftis, Michael Bauer, Bryce S. RichardsAbstract:The application of luminescent down-shifting (LDS) has been shown to improve the short wavelength response of a variety of different photovoltaic devices. Cadmium sulphide/cadmium telluride (CdS/CdTe) heterojunction devices possess a great potential for improvement via LDS due to the parasitic absorption of blue light by the CdS buffer layer. This work is the first to investigate LDS applied to mini-modules (72 cm 2 active area) cut from full-size CdTe modules from a production line. The addition of LDS layers containing Lumogen Yellow 083 and Violet 570 dyes was demonstrated to increase the short circuit Current Density (J SC) of the mini-module by up to 9% relative. It was shown that the addition of the Yellow 083 dye alone more than doubles the short wavelength (300-500 nm) response of CdTe mini-modules. External quantum efficiency measurements are presented that clearly identified the wavelength range of photoCurrent enhancement, while increased efficiency was confirmed with Current-voltage (I-V) measurements. ?? 2012 Elsevier B.V. All rights reserved.
Fabian Fertig - One of the best experts on this subject based on the ideXlab platform.
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An empirical method for imaging the short circuit Current Density in silicon solar cells based on dark lock-in thermography
Solar Energy Materials and Solar Cells, 2015Co-Authors: Otwin Breitenstein, Fabian Fertig, Jan BauerAbstract:Abstract The most straightforward way to map the photo-induced short circuit Current Density ( J sc ) in solar cells is light beam-induced Current (LBIC) mapping. Recently several methods for J sc imaging based on camera-based photoluminescence and illuminated lock-in thermography imaging were proposed. This letter reports an alternative method for J sc imaging, which is solely based on the evaluation of dark lock-in thermography images. This method is particularly advantageous to improve the accuracy of dark lock-in thermography based local efficiency analysis of solar cells.
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Short-Circuit Current Density Imaging Methods for Silicon Solar Cells
Energy Procedia, 2015Co-Authors: Fabian Fertig, Otwin Breitenstein, M. C. Schubert, Ino Geisemeyer, Hannes Höffler, Milan Padilla, Stefan ReinAbstract:Abstract Recently, several novel methods have been proposed to image Short-Circuit Current Density j sc based on diverse physical principles. This work compares these methods and points out physical limitations, advantages and drawbacks of each approach. One method based on photoluminescence (PL) imaging and two methods based on dark and illuminated lock-in thermography (DLIT / ILIT) are discussed. As a versatile reference technique for j sc mapping, spectrally-resolved light-beam induced Current (SR-LBIC) is applied. Experimental results for crystalline silicon solar cells with varying substrate properties, rear-side passivation schemes and process-induced defects are presented. Investigated parameters are quantitative accuracy of local j sc , spatial resolution, measurement time, spectral excitation dependency and calibration. Furthermore, robustness towards locally increased series resistance R s and injection-dependent recombination is discussed along with proneness to artefacts due to local shunts, spatially varying optics and photogeneration, and fitting algorithm artefacts.
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Short-Circuit Current Density Imaging Methods for Silicon Solar Cells
Energy Procedia, 2015Co-Authors: Fabian Fertig, Mario Padilla, H. H?ffler, Otwin Breitenstein, M. C. Schubert, Ino Geisemeyer, Stefan ReinAbstract:? 2015 The Authors.Recently, several novel methods have been proposed to image Short-Circuit Current Density jsc based on diverse physical principles. This work compares these methods and points out physical limitations, advantages and drawbacks of each approach. One method based on photoluminescence (PL) imaging and two methods based on dark and illuminated lock-in thermography (DLIT / ILIT) are discussed. As a versatile reference technique for jsc mapping, spectrally-resolved light-beam induced Current (SR-LBIC) is applied. Experimental results for crystalline silicon solar cells with varying substrate properties, rear-side passivation schemes and process-induced defects are presented. Investigated parameters are quantitative accuracy of local jsc, spatial resolution, measurement time, spectral excitation dependency and calibration. Furthermore, robustness towards locally increased series resistance Rs and injection-dependent recombination is discussed along with proneness to artefacts due to local shunts, spatially varying optics and photogeneration, and fitting algorithm artefacts.
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Short-Circuit Current Density imaging of crystalline silicon solar cells via lock-in thermography: Robustness and simplifications
Journal of Applied Physics, 2014Co-Authors: Fabian Fertig, Johannes Greulich, Stefan ReinAbstract:Spatially resolved determination of solar cell parameters is beneficial for loss analysis and optimization of conversion efficiency. One key parameter that has been challenging to access by an imaging technique on solar cell level is Short-Circuit Current Density. This work discusses the robustness of a recently suggested approach to determine Short-Circuit Current Density spatially resolved based on a series of lock-in thermography images and options for a simplified image acquisition procedure. For an accurate result, one or two emissivity-corrected illuminated lock-in thermography images and one dark lock-in thermography image have to be recorded. The dark lock-in thermography image can be omitted if local shunts are negligible. Furthermore, it is shown that omitting the correction of lock-in thermography images for local emissivity variations only leads to minor distortions for standard silicon solar cells. Hence, adequate acquisition of one image only is sufficient to generate a meaningful map of Short-Circuit Current Density. Beyond that, this work illustrates the underlying physics of the recently proposed method and demonstrates its robustness concerning varying excitation conditions and locally increased series resistance. Experimentally gained Short-Circuit Current Density images are validated for monochromatic illumination in comparison to the reference method of light-beam induced Current.
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Spatially resolved determination of the Short-Circuit Current Density of silicon solar cells via lock-in thermography
Applied Physics Letters, 2014Co-Authors: Fabian Fertig, Johannes Greulich, Stefan ReinAbstract:We present a spatially resolved method to determine the Short-Circuit Current Density of crystalline silicon solar cells by means of lock-in thermography. The method utilizes the property of crystalline silicon solar cells that the Short-Circuit Current does not differ significantly from the illuminated Current under moderate reverse bias. Since lock-in thermography images locally dissipated power Density, this information is exploited to extract values of spatially resolved Current Density under Short-Circuit conditions. In order to obtain an accurate result, one or two illuminated lock-in thermography images and one dark lock-in thermography image need to be recorded. The method can be simplified in a way that only one image is required to generate a meaningful Short-Circuit Current Density map. The proposed method is theoretically motivated, and experimentally validated for monochromatic illumination in comparison to the reference method of light-beam induced Current. © 2014 AIP Publishing LLC.
M. C. Schubert - One of the best experts on this subject based on the ideXlab platform.
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Short-Circuit Current Density Imaging Methods for Silicon Solar Cells
Energy Procedia, 2015Co-Authors: Fabian Fertig, Otwin Breitenstein, M. C. Schubert, Ino Geisemeyer, Hannes Höffler, Milan Padilla, Stefan ReinAbstract:Abstract Recently, several novel methods have been proposed to image Short-Circuit Current Density j sc based on diverse physical principles. This work compares these methods and points out physical limitations, advantages and drawbacks of each approach. One method based on photoluminescence (PL) imaging and two methods based on dark and illuminated lock-in thermography (DLIT / ILIT) are discussed. As a versatile reference technique for j sc mapping, spectrally-resolved light-beam induced Current (SR-LBIC) is applied. Experimental results for crystalline silicon solar cells with varying substrate properties, rear-side passivation schemes and process-induced defects are presented. Investigated parameters are quantitative accuracy of local j sc , spatial resolution, measurement time, spectral excitation dependency and calibration. Furthermore, robustness towards locally increased series resistance R s and injection-dependent recombination is discussed along with proneness to artefacts due to local shunts, spatially varying optics and photogeneration, and fitting algorithm artefacts.
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Short-Circuit Current Density Imaging Methods for Silicon Solar Cells
Energy Procedia, 2015Co-Authors: Fabian Fertig, Mario Padilla, H. H?ffler, Otwin Breitenstein, M. C. Schubert, Ino Geisemeyer, Stefan ReinAbstract:? 2015 The Authors.Recently, several novel methods have been proposed to image Short-Circuit Current Density jsc based on diverse physical principles. This work compares these methods and points out physical limitations, advantages and drawbacks of each approach. One method based on photoluminescence (PL) imaging and two methods based on dark and illuminated lock-in thermography (DLIT / ILIT) are discussed. As a versatile reference technique for jsc mapping, spectrally-resolved light-beam induced Current (SR-LBIC) is applied. Experimental results for crystalline silicon solar cells with varying substrate properties, rear-side passivation schemes and process-induced defects are presented. Investigated parameters are quantitative accuracy of local jsc, spatial resolution, measurement time, spectral excitation dependency and calibration. Furthermore, robustness towards locally increased series resistance Rs and injection-dependent recombination is discussed along with proneness to artefacts due to local shunts, spatially varying optics and photogeneration, and fitting algorithm artefacts.
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Short-Circuit Current Density mapping for solar cells
Solar Energy Materials and Solar Cells, 2014Co-Authors: Mario Padilla, Benjamin Thaidigsmann, Bernhard Michl, Wilhelm Warta, M. C. SchubertAbstract:A map of local Short-Circuit Current Density (JSC) of a solar cell at standard irradiance spectra is a desirable source of information for Current-loss analysis and device optimization. In this work, we present a new and easily implementable method to obtain such JSC maps as well as local external quantum efficiency graphs with a spatial resolution of about 100 ??m, exemplified for silicon solar cells. The method is based on a pixel by pixel interpolation of external quantum efficiency maps obtained by spectrally resolved light-beam induced Current measurements (SR-LBIC). The local data is integrated with an AM1.5G spectrum to obtain a JSC map with no additional measurement time beyond SR-LBIC image acquisition. The averaged Currents over a map are in good agreement with global Current-voltage measurements. Some of the possible applications of this method are presented and exemplified, including local quantum efficiency of a cast-mono solar cell, separation of JSC contributions from front side and bulk, quantitative determination of the electrical shading effect in IBC cells, the impact of the irradiance spectrum on local JSC for indoor photovoltaic applications and also the separation of optical and electrical Current losses with newly introduced Pseudo-JSC maps based on internal quantum efficiency maps. Finally, the resulting JSC maps also present valuable information for several existing local cell-parameter imaging methods. This basic approach leads to an easily accessible, spatially resolved Short-Circuit Current loss-analysis, which is in principle applicable to any solar cell structure. ?? 2013 Elsevier B.V.
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Short-Circuit Current Density mapping for solar cells
Solar Energy Materials and Solar Cells, 2014Co-Authors: Milan Padilla, Benjamin Thaidigsmann, Bernhard Michl, Wilhelm Warta, M. C. SchubertAbstract:Abstract A map of local Short-Circuit Current Density ( J SC ) of a solar cell at standard irradiance spectra is a desirable source of information for Current-loss analysis and device optimization. In this work, we present a new and easily implementable method to obtain such J SC maps as well as local external quantum efficiency graphs with a spatial resolution of about 100 µm, exemplified for silicon solar cells. The method is based on a pixel by pixel interpolation of external quantum efficiency maps obtained by spectrally resolved light-beam induced Current measurements (SR-LBIC). The local data is integrated with an AM1.5G spectrum to obtain a J SC map with no additional measurement time beyond SR-LBIC image acquisition. The averaged Currents over a map are in good agreement with global Current–voltage measurements. Some of the possible applications of this method are presented and exemplified, including local quantum efficiency of a cast-mono solar cell, separation of J SC contributions from front side and bulk, quantitative determination of the electrical shading effect in IBC cells, the impact of the irradiance spectrum on local J SC for indoor photovoltaic applications and also the separation of optical and electrical Current losses with newly introduced Pseudo- J SC maps based on internal quantum efficiency maps. Finally, the resulting J SC maps also present valuable information for several existing local cell-parameter imaging methods. This basic approach leads to an easily accessible, spatially resolved Short-Circuit Current loss-analysis, which is in principle applicable to any solar cell structure.
Alan J. Heeger - One of the best experts on this subject based on the ideXlab platform.
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Small‐Bandgap Polymer Solar Cells with Unprecedented Short‐Circuit Current Density and High Fill Factor
Advanced Materials, 2015Co-Authors: Hyosung Choi, Mathieu Leclerc, Pierre-olivier Morin, Bright Walker, Seo-jin Ko, Alan J. HeegerAbstract:Small-bandgap polymer solar cells (PSCs) with a thick bulk heterojunction film of 340 nm exhibit high power conversion efficiencies of 9.40% resulting from high Short-Circuit Current Density (JSC ) of 20.07 mA cm(-2) and fill factor of 0.70. This remarkable efficiency is attributed to maximized light absorption by the thick active layer and minimized recombination by the optimized lateral and vertical morphology through the processing additive.
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Small-bandgap polymer solar cells with unprecedented Short-Circuit Current Density and high fill factor.
Advanced materials (Deerfield Beach Fla.), 2015Co-Authors: Hyosung Choi, Byoung Hoon Lee, Mathieu Leclerc, Pierre-olivier Morin, Bright Walker, Seo-jin Ko, Taehyo Kim, Jin Young Kim, Alan J. HeegerAbstract:Small-bandgap polymer solar cells (PSCs) with a thick bulk heterojunction film of 340 nm exhibit high power conversion efficiencies of 9.40% resulting from high Short-Circuit Current Density (JSC ) of 20.07 mA cm(-2) and fill factor of 0.70. This remarkable efficiency is attributed to maximized light absorption by the thick active layer and minimized recombination by the optimized lateral and vertical morphology through the processing additive.