46 results on '"David Hinken"'
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2. Multi‐Spectrum Method for the Determination of the Spectral Responsivity and the Short‐Circuit Current of Photovoltaic Devices
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David Hinken, Carsten Schinke, Karsten Bothe, and Rolf Brendel
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Energy Engineering and Power Technology ,Electrical and Electronic Engineering ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials - Published
- 2023
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3. Solar cell efficiency tables (Version 60)
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Martin A. Green, Ewan D. Dunlop, Jochen Hohl‐Ebinger, Masahiro Yoshita, Nikos Kopidakis, Karsten Bothe, David Hinken, Michael Rauer, Xiaojing Hao, and Publica
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energy conversion efficiency ,photovoltaic efficiency ,Renewable Energy, Sustainability and the Environment ,solar cell efficiency ,Electrical and Electronic Engineering ,Condensed Matter Physics ,energy efficiency ,Electronic, Optical and Magnetic Materials - Abstract
Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined, and new entries since January 2022 are reviewed. An appendix describing temporary electrical contacting of large-area solar cells approaches and terminology is also included.
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- 2022
4. Determination of base doping concentration of silicon solar cells from light IV-curves
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Klaus Ramspeck, Lothar Komp, Stefan Dauwe, Karsten Bothe, David Hinken, Martin Wolf, and Michael Meixner
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- 2022
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5. Corrigendum: Calibrating spectrometers for measurements of the spectral irradiance caused by solar radiation (2020 Metrologia 57 065027)
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Carsten Schinke, Hendrik Pollex, David Hinken, Martin Wolf, Karsten Bothe, Ingo Kröger, Saulius Nevas, and Stefan Winter
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General Engineering - Abstract
We correct an error in equation (60) of the original publication.
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- 2023
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6. Interlaboratory comparison of short-circuit current versus irradiance linearity measurements of photovoltaic devices
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Martin Bliss, Ingo Kroeger, Elena Salis, Karsten Bothe, S. Winter, Jochen Hohl-Ebinger, David Hinken, Thomas R. Betts, Ralph Gottschalg, Harald Müllejans, and Publica
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Renewable Energy, Sustainability and the Environment ,Computer science ,Spectral responsivity ,020209 energy ,Photovoltaic system ,Irradiance ,Uncertainty budget ,Linearity ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Reliability engineering ,0202 electrical engineering, electronic engineering, information engineering ,White light ,General Materials Science ,Solar simulator ,0210 nano-technology ,Short circuit - Abstract
This work presents the results of the first interlaboratory comparison of linearity measurements of short-circuit current versus irradiance that includes a wide variety of photovoltaic (PV) device types, from reference cells to full-size modules. The aim of this inter-comparison was to compare the methods employed and to collect new inputs useful for the revision of the standard IEC 60904-10, which deals with linearity measurements for PV devices. The procedures and facilities employed by the partners include the differential spectral responsivity, the white light response, the solar simulator method and the two-lamp method. The facilities are generically described and compared and their main sources of uncertainty are discussed. Comparison results show good agreement within declared uncertainties between all partners. A few minor exceptions under low-light conditions raise questions of possible uncertainty underestimation for these specific conditions. The overall outcome of the comparison also highlights the importance of considering correlations in the uncertainty budget, which can potentially improve the overall stated uncertainty. A critical review is made of the data analysis adopted in the standard IEC 60904-10 to calculate the linearity degree of the short-circuit current towards irradiance. The analysis review suggests a way to make results based on different methods more comparable and less prone to erroneous linearity assessment.
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- 2019
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7. Results of four European round-robins on short-circuit current temperature coefficient measurements of photovoltaic devices of different size
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Diego Pavanello, Sebastian Dittmann, Elena Salis, Jochen Hohl-Ebinger, Karsten Bothe, J. Dubard, I. Kröger, S. Winter, Gabi Friesen, Harald Müllejans, David Hinken, T. Gandy, and Publica
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Renewable Energy, Sustainability and the Environment ,Messtechnik und Produktionskontrolle ,020209 energy ,Nuclear engineering ,Photovoltaic system ,Irradiance ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Copper indium gallium selenide solar cells ,photovoltaic ,Silicium-Photovoltaik ,bare cells to full-size modules ,short-circuit current temperature coefficient intercomparisons ,Photovoltaik ,0202 electrical engineering, electronic engineering, information engineering ,spectral temperature coefficient ,Environmental science ,Standard test ,General Materials Science ,Current (fluid) ,0210 nano-technology ,Short circuit ,Temperature coefficient - Abstract
Within the EURAMET ENG55 “PhotoClass” project, several characteristics of photovoltaic (PV) devices beyond their performance at Standard Test Conditions were investigated, including measurements at varying irradiance and temperature. Four groups of PV devices of different size and technology were prepared and corresponding round-robins were run between partner laboratories with substantially different facilities and methods – namely based on spectral or integral measurements. This paper presents the outcome of the four inter-laboratory comparisons dealing with temperature coefficient measurements of the short-circuit current of PV devices, from reference-cell size to full-size commercial modules of mainly several c-Si technologies, but also with some examples of CIGS and GaAs devices. The measurement results are compared via En number assessment, hence including measurement uncertainties. The main outcome of this measurement exercise is a very good agreement of all the laboratories although completely different approaches were applied. In some cases, laboratory measurement uncertainties are even considered rather conservative and could therefore be revised. Furthermore, a comparison between bare cells and commercial modules of the same technology is made, which may represent useful information for PV manufacturers.
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- 2019
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8. Accuracy of Simplifications for Spectral Responsivity Measurements of Solar Cells
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Byungsul Min, Karsten Bothe, Carsten Schinke, and David Hinken
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010302 applied physics ,Physics ,Spectrum (functional analysis) ,Photovoltaic system ,Irradiance ,Scale (descriptive set theory) ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,Computational physics ,law.invention ,Wavelength ,Nonlinear system ,law ,0103 physical sciences ,Solar cell ,Solar simulator ,Electrical and Electronic Engineering ,0210 nano-technology - Abstract
The determination of the spectral responsivity is an essential part of solar cell characterization. Since solar simulators only approximate the reference spectrum, a spectral mismatch correction has to be performed. This correction procedure requires spectral responsivity data. Apart from the complete differential spectral responsivity procedure, the IEC 60904-8 standard defines four simplifications. In this paper, we provide information on the variations in the spectral responsivity curves for these simplifications. We show that for nonlinear front junction cells, deviations predominantly occur at wavelengths above 700 nm and become largest around 1000 nm. While we found a maximum deviation of 30% for the simplification with lowest requirements in bias irradiance, all other simplifications yield deviations below 10%. For a nonlinear cell measured relative to a world photovoltaic scale reference cell using a class A solar simulator, this transfers to a deviation below 0.01% in the spectral mismatch factor. If one depends on the use of a simplification, we recommend using the multicolor approach. Even though the singlecolor approach might yield lower deviations, this approach requires knowledge about the maximum in the spectral responsivity, which is not generally known in advance of the measurement. Accepting a slightly higher deviation, the white bias approach is a recommendable alternative.
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- 2018
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9. Impact of Contacting Geometries When Measuring Fill Factors of Solar Cell Current–Voltage Characteristics
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Martin Wolf, David Hinken, Christian Kruse, Karsten Bothe, Carsten Schinke, and Rolf Brendel
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Materials science ,Tandem ,Busbar ,020209 energy ,Analytical chemistry ,02 engineering and technology ,Sense (electronics) ,Condensed Matter Physics ,Measure (mathematics) ,Molecular physics ,Electronic, Optical and Magnetic Materials ,law.invention ,Electrical resistivity and conductivity ,law ,Solar cell ,0202 electrical engineering, electronic engineering, information engineering ,Sensitivity (control systems) ,Electric potential ,Electrical and Electronic Engineering - Abstract
We analyze the influence of a variety of different contacting geometries on the fill factor (FF) of solar cell I–V measurements. For this analysis, we compare a wide variety of modeled and measured FFs of Si solar cells. We consistently find large FF differences between individual contacting geometries. These differences amount to up to 3 ${\%_{{\rm abs}}}$ for high busbar resistivities of up to 40 $\Omega/\hbox{m}$ . We analyze the contacting geometries for their sensitivity on uncontrolled variations of the contacting resistances. In this analysis, we find that using triplet rather than tandem configurations and using a larger number of test probes reduces the impact of varying contacting resistances to below 0.02 ${\%_{{\rm abs}}}$ . We propose a contacting geometry that we consider to be suitable for calibrated I–V measurements. This contacting scheme is a configuration with a total of five triplets consisting of two current probes and one sense probe. The sense probe is positioned to measure the average busbar potential between the current probes. This is the optimal contacting geometry in terms of a low sensitivity to the busbar resistivity and variations of contacting resistances. In addition, this geometry does not impose unnecessarily large mechanical stress to the cell under measurement.
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- 2017
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10. Calibrating spectrometers for measurements of the spectral irradiance caused by solar radiation
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Karsten Bothe, David Hinken, I. Kröger, S. Winter, Hendrik Pollex, Saulius Nevas, Carsten Schinke, and Martin Wolf
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Solar cells ,Electric lamps ,Irradiance ,Radiation ,Monte Carlo procedures ,Spectrometer ,Calibration standard ,Calibration laboratories ,Spectroradiometer ,Calibration ,Solar radiation ,Uncertainty contributions ,Solar simulator ,Remote sensing ,Physics ,Signal to noise ratio ,General Engineering ,Stray light ,Science and Technology ,Dewey Decimal Classification::600 | Technik ,Spectral irradiance ,Measurement uncertainty analysis ,Application examples ,Uncertainty analysis ,ddc:600 ,Guide to the expression of uncertainty in measurements - Abstract
Measuring the spectral irradiance of solar radiation is required in many fields of science and technology. In this work, we present an in-depth discussion of the measuring procedure and required corrections for such measurements. We also describe our measurement uncertainty analysis, which is based on a Monte-Carlo procedure in accordance with the Guide to the expression of uncertainty in measurement (JCGM, Paris, 2008). For this purpose, fifteen uncertainty sources are identified, analyzed and described analytically. As a specific application example, we describe the instrumentation and procedure for determining the spectral irradiance of a solar simulator at the ISO/IEC 17 025 accredited solar cell calibration laboratory ISFH CalTeC and the corresponding measurement uncertainty analysis. Moreover, we provide a Python implementation for this calculation along with the paper. We show that for state-of-the-art instrumentation, significant uncertainty contributions arise from the reference lamp (primary calibration standard), stray light and signal-to-noise ratio. If sharp spectral features are present (which is common, e.g. for Xenon lamps), spectral bandwidth and wavelength uncertainty also contribute significantly to the overall uncertainty.
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- 2020
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11. High-Efficiency Modules With Passivated Emitter and Rear Solar Cells—An Analysis of Electrical and Optical Losses
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Marc Köntges, Susanne Blankemeyer, Robert Witteck, Malte R. Vogt, Henning Schulte-Huxel, Thorsten Dullweber, Karsten Bothe, Hendrik Holst, Till Brendemühl, David Hinken, and Rolf Brendel
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010302 applied physics ,Interconnection ,Power loss ,Materials science ,business.industry ,Photovoltaic system ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,0103 physical sciences ,Optoelectronics ,Electrical and Electronic Engineering ,0210 nano-technology ,business ,Common emitter ,Nominal power (photovoltaic) - Abstract
We process a photovoltaic (PV) module with 120 half passivated emitter and rear cells that exhibits an independently confirmed power of 303.2 W and a module efficiency of 20.2% (aperture area). The cells are optimized for operation within the module. We enhance light harvesting from the inactive spacing between the cells and the cell interconnect ribbons. Additionally, we reduce the inactive area to below 3% of the aperture module area. The impact of these measures is analyzed by ray-tracing simulations of the module. Using a numerical model, we analyze and predict the module performance based on the individual cell measurements and the optical simulations. We determine the power loss due to series interconnection of the solar cells to be 1.5%. This is compensated by a gain in current of 1.8% caused by the change of the optical environment of the cells in the module. We achieve a good agreement between simulations and experiments, both showing no cell-to-module power loss.
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- 2017
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12. Effective Diffusion Length and Bulk Saturation Current Density Imaging in Solar Cells by Spectrally Filtered Luminescence Imaging
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Karsten Bothe, David Hinken, Felix Frühauf, and Otwin Breitenstein
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010302 applied physics ,Materials science ,Photoluminescence ,Photon ,business.industry ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,Computational physics ,law.invention ,Optics ,law ,Saturation current ,0103 physical sciences ,Solar cell ,Electrical and Electronic Engineering ,Diffusion (business) ,0210 nano-technology ,Luminescence ,business ,Image resolution ,Current density - Abstract
Most methods for interpreting electroluminescence (EL) or photoluminescence (PL) images of solar cells evaluate the local diode voltages but not the local luminescence intensity itself. One exception is the Fuyuki approximation, which assumes that the local value of the luminescence signal is proportional to the local effective diffusion length. This dependence has been derived for infinitely thick solar cells and neglects self-absorption of the luminescence photons. However, for real solar cells and imaging conditions, with increasing diffusion length, the luminescence signal approaches a limiting value; hence, the Fuyuki approximation no longer holds. In this paper, we compare EL and PL images of multicrystalline solar cells using different kinds of light filtering and find that gentle shortpass filtering is useful for avoiding optical artifacts. Based on earlier calculations, a physically founded formula for the dependence of the gently shortpass-filtered luminescence signal on the bulk diffusion length, for a given rear surface recombination velocity, is presented. Since this formula only barely allows us to calculate the diffusion length from the luminescence signal, a simplified approximate formula is proposed, and its accuracy is checked. This method is tested on EL and ${V_{{{\rm oc}}}}$ PL images of solar cells. We find that for a typical industrial multicrystalline Al-backside solar cell, the obtained effective diffusion length images correlate well with such images obtained by spectral LBIC image evaluation. In addition, the saturation current density images correlate well with such images obtained by dark lock-in thermography, which show a much lower spatial resolution. The main limitation of the proposed method is that it is basically approximate and needs some fitting parameters.
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- 2016
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13. Optical Constants of UV Transparent EVA and the Impact on the PV Module Output Power under Realistic Irradiation
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Henning Schulte-Huxel, Malte R. Vogt, Marc Köntges, David Hinken, Susanne Blankemeyer, Robert Witteck, Hendrik Holst, Matthias Winter, Byungsul Min, Rolf Brendel, Carsten Schinke, Ingo Ahrens, and Karsten Bothe
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Spectroscopic ellipsometry ,3D optical data storage ,Materials science ,Spectral power distribution ,Refractive index ,02 engineering and technology ,PV modules ,01 natural sciences ,Capillary flow ,Irradiation conditions ,law.invention ,Ethylene ,chemistry.chemical_compound ,Ethylene vinyl acetates ,Optics ,Energy(all) ,law ,0103 physical sciences ,Solar cell ,otorhinolaryngologic diseases ,ddc:530 ,Standard test condition (STC) ,Irradiation ,Ray tracing simulation ,Thermoplastic elastomers ,Konferenzschrift ,010302 applied physics ,Complex refractive index ,business.industry ,Photovoltaic cells ,UV transmission ,Ethylene-vinyl acetate ,Ray tracing ,Crystalline materials ,021001 nanoscience & nanotechnology ,Reflection measurements ,chemistry ,ethylene vinyl acetate (EVA) ,Ray tracing (graphics) ,Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik ,sense organs ,Angular distribution ,0210 nano-technology ,business ,Short circuit - Abstract
We measure and discuss the complex refractive index of conventional ethylene vinyl acetate (EVA) and an EVA with enhanced UV-transmission based on spectroscopic ellipsometry, transmission and reflection measurements over the wavelength range from 300-1200 nm. Ray tracing of entire solar cell modules using this optical data predicts a 1.3% increase in short circuit current density (Jsc) at standard test conditions for EVA with enhanced UV transmission. This is in good agreement with laboratory experiments of test modules that result in a 1.4% increase in Jsc by using a UV transparent instead of a conventional EVA. Further, ray tracing simulations with realistic irradiation conditions with respect to angular and spectral distribution reveal an even larger Jsc increase of 1.9% in the yearly average. This increase is largest in the summer months with an increase of up to 2.3%. German Federal Ministry for Economic Affairs and Energy/0325641
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- 2016
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14. Approximating the determination of the spectral responsivity of solar cells
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David Hinken, Carsten Schinke, Ingo Ahrens, Karsten Bothe, and Tobias Gandy
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Physics ,Wavelength ,law ,Photovoltaic system ,Solar cell ,Calibration ,Irradiance ,Scale (descriptive set theory) ,Solar simulator ,Crystalline silicon ,law.invention ,Computational physics - Abstract
The determination of the spectral responsivity is an essential part of solar cell calibration. Apart from the complete differential spectral responsivity procedure, which yields the most accurate results, the IEC 60904-8 defines four simplifications. We provide detailed information on the expected variations in the calculated spectral responsivity curves for the different simplifications compared to the complete procedure. For non-linear crystalline silicon front junction solar cells, we show that deviations mainly occur at wavelengths above 700 nm and become largest between 1000 to 1200 nm. Even though we found a maximum deviation in spectral responsivity of 7% for the simplification with lowest requirements in bias irradiance, all other simplifications yield deviations well below 3%. This transforms into a deviation of 0.01% in the spectral mismatch factor for an industrial PERC solar cell when using a typical world photovoltaic scale (WPVS) reference solar cell and a class A two-lamp solar simulator. If you are reliant on the use of a simplification, we recommend using the multicolour approach. Even though the singlecolour approach might yield lower deviations in specific cases, it requires knowledge about the maximum in the spectral responsivity, which is not generally known in advance of the measurement. Accepting a slightly higher deviation, the white bias approach is a recommendable alternative.
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- 2018
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15. Optimized Interconnection of Passivated Emitter and Rear Cells by Experimentally Verified Modeling
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Marc Köntges, Susanne Blankemeyer, Malte R. Vogt, Henning Schulte-Huxel, Robert Witteck, David Hinken, Karsten Bothe, Jens Müller, and Rolf Brendel
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Production line ,Interconnection ,Materials science ,Cell interconnection ,business.industry ,020209 energy ,Thyristor ,02 engineering and technology ,Edge (geometry) ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,0202 electrical engineering, electronic engineering, information engineering ,Measurement uncertainty ,Optoelectronics ,Power output ,Electrical and Electronic Engineering ,0210 nano-technology ,business ,Common emitter - Abstract
Recent reports about new cell efficiency records are highlighting the continuing development of passivated emitter and rear cells (PERC). Additionally, volume production has started, forming the basis for cutting edge solar modules. However, transferring the high efficiency of the cells into a module requires an adaptation of the conventional front metallization and of the cell interconnection design. This paper studies and compares the module output of various cell interconnection technologies, including conventional cell interconnection ribbons and wires. We fabricate solar cells and characterize their electrical and optical properties. From the cells, we build experimental modules with various cell interconnection technologies. We determine the optical and electrical characteristics of the experimental modules. Based on our experimental results, we develop an analytical model that reproduces the power output of the experimental modules within the measurement uncertainty. The analytical model is then applied to simulate various cell interconnection technologies employing halved cells, optical enhanced cell interconnectors, and multiwires. We also consider the effect of enhancing the cell-to-cell spacing. Based on the experimentally verified simulations, we propose an optimized cell interconnection for a 60-PERC module that achieves a power output of 323 W. Our simulations reveal that wires combined with halved cells show the best module performance. However, applying light-harvesting structures to the cell interconnection ribbons is an attractive alternative for upgrading existing production lines.
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- 2016
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16. Towards an improved Laplacian-based photoluminescence image evaluation method
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Otwin Breitenstein, Jan Bauer, David Hinken, and Karsten Bothe
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Equivalent series resistance ,Renewable Energy, Sustainability and the Environment ,Computer science ,Analytical chemistry ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Local analysis ,Saturation current ,Equivalent circuit ,Sensitivity (control systems) ,Laplace operator ,Scaling ,Algorithm ,Diode - Abstract
In a previous contribution it was found by evaluating 2-dimensional device simulation-based photoluminescence (PL) images of solar cells that the previous methods of PL image evaluation give good results for imaging the local series resistance, but lead to an erroneous distribution of an inhomogeneous saturation current density J01. This is caused by the model of independent diodes used in these evaluation methods, which does not take into account the distributed character of the series resistance and horizontal balancing currents occurring in inhomogeneous solar cells. In this contribution it is checked whether two alternative PL evaluation methods, which were already published but did not become popular yet, may overcome this problem. These are the differential luminescence imaging technique proposed by Rau et al. and the Laplacian-based method proposed by Glatthaar et al. By simulating PL images of a model device based on a 2-dimensional equivalent circuit with a known distribution of J01 and applying these PL evaluation methods, retrieved images of J01 are obtained and compared with the input J01 distribution. It is found that the differential luminescence imaging technique, at least in its presently used form, leads to wrong results, as the traditional PL evaluation techniques do. The Laplacian-based method, on the other hand, indeed has the potential to image J01 correctly. However, until now this method lacks in sensitivity. In this contribution some improvements are proposed, which may enhance the sensitivity of the Laplacian-based method. One important improvement is to enable a scaling measurement at a high instead of a low current resp. illumination intensity. Thereby the signal-to-noise ratio of the scaling measurement, which until now limited the accuracy of the whole PL evaluation, may be improved. Another proposal is that the actual PL measurement is performed under open circuit condition and not under current extraction. First experimental results show the effectiveness of this new method, but limitations still remain.
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- 2015
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17. The reliability of thermography- and luminescence-based series resistance and saturation current density imaging
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Jan Bauer, Karsten Bothe, David Hinken, and Otwin Breitenstein
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Materials science ,Equivalent series resistance ,Pixel ,Renewable Energy, Sustainability and the Environment ,business.industry ,Electroluminescence ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,law.invention ,Optics ,Saturation current ,law ,Thermography ,Solar cell ,business ,Diode ,Common emitter - Abstract
The conventional quantitative evaluation of dark lock-in thermography (DLIT), electroluminescence (EL), and photoluminescence (PL) images of solar cells is based on the model of independent diodes, where each image pixel is assumed to be connected with the terminals by an independent series resistance. In reality, however, the solar cell represents a 2-dimensional resistance-diode network. In this work solar cells containing well-defined spatial distributions of the saturation current density J01 and also containing J02-type and ohmic shunts are modeled for various externally applied biases and illumination conditions realistically as a 2-dimensional resistance-diode network. The resulting local diode voltage distributions are converted into DLIT, EL and PL images, which are further processed by conventional evaluation methods, which rely on the simple model of independent diodes. These are the so-called “Local-IV” method for the DLIT analysis, which may be supported by EL results to obtain series resistance images, and “C-DCR” for the PL analysis. This leads to calculated images of the local effective series resistance Rs and of J01. Regarding the resulting Rs images, PL shows the expected series resistance distribution and is not affected by the shunt regions. The DLIT–EL Rs images instead yield expected values only in the homogeneous regions, which are not affected by the assumed shunts. DLIT–EL determines higher values of Rs in local shunt regions and lower values around these regions and in spatially extended shunt regions. Regarding the J01 images both methods again give the expected results if J01 is distributed homogeneously. However, in the shunted regions, PL suffers from balancing currents within the emitter and DLIT from optical blurring. By comparing local and extended regions of increased J01 we find that DLIT approximates the expected J01 value better than PL, which clearly underestimates even extended local maxima of J01. For a local current analysis of silicon solar cells we recommend the use of DLIT for the determination of J01 images and PL for the determination of Rs images.
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- 2015
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18. Results of the round robin calibration of reference solar cells within the PhotoClass project
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Elena Salis, Karsten Bothe, Ralph Gottschalg, Martin Bliss, Thomas R. Betts, Jochen Hohl-Ebinger, Werner Herrmann, Lorentz Rimmelspacher, Gabi Friesen, David Hinken, D. Friedrich, Diego Pavanello, S. Winter, I. Kröger, Jimmy Dubard, Sebastian Dittmann, Harald Müllejans, Johannes Stang, and Publica
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Solar cells ,Technology ,III-V semiconductors ,Calibration chain ,02 engineering and technology ,01 natural sciences ,Software testing ,Crystalline silicons ,Solar power generation ,010309 optics ,Gallium arsenide ,Round robin ,0103 physical sciences ,Standard test conditions ,Calibration ,Standard test ,Standard test condition (STC) ,Crystalline silicon ,Testing laboratories ,Safety, Risk, Reliability and Quality ,Remote sensing ,Intercomparisons ,Routers ,Photovoltaic system ,Comparability ,Reference solar cell ,Research programs ,021001 nanoscience & nanotechnology ,Dewey Decimal Classification::600 | Technik ,Metrology ,Environmental science ,Calibration values ,0210 nano-technology ,Laboratories ,ddc:600 - Abstract
An intercomparison of terrestrial photovoltaic (PV) calibrations was performed among a number of European calibration and testing laboratories that participated in the European Metrology Research Program (EMRP) project “PhotoClass”. The purpose of this intercomparison was to evaluate the comparability of calibration and testing services within the stated uncertainties of the individual laboratories. The calibration objects were two world photovoltaic scale (WPVS)-type reference solar cells, one made from crystalline silicon and one made from GaAs. The calibration value (CV) was the short-circuit current under standard test conditions (ISTC). In conclusion, it was found that the CVs are all consistent within the stated uncertainties. This result strengthens the reliance in the calibration chain and in the PV calibration infrastructure in Europe.
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- 2018
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19. Resistive Power Loss Analysis of PV Modules Made From Halved 15.6 × 15.6 cm2 Silicon PERC Solar Cells With Efficiencies up to 20.0%
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Jens Müller, Heike Kohlenberg, Karsten Bothe, Ulrike Sonntag, David Hinken, Rolf Brendel, Marc Köntges, Susanne Blankemeyer, and Thorsten Dullweber
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Interconnection ,Resistive touchscreen ,Materials science ,Silicon ,Equivalent series resistance ,business.industry ,Photovoltaic system ,chemistry.chemical_element ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,law.invention ,Monocrystalline silicon ,chemistry ,law ,Solar cell ,Optoelectronics ,Electrical and Electronic Engineering ,business ,Common emitter - Abstract
In photovoltaic (PV) modules, the interconnection of solar cells is critical in terms of mechanical stability and resistive power losses. In this study, we analyze the interconnection of large-area 15.6 × 15.6 cm 2 industrial p-type passivated emitter and rear cell (PERC) solar cells in terms of resistive losses. For our analysis, we prepare a 3 × 3 minimodule from PERC solar cells with soldering pads and efficiencies up to 20.0%. We measure a significant cell-to-module (CTM) power loss of 8% at this module. For comparison, we prepare a 3 × 6 module consisting of halved 7.8 × 15.6 cm 2 PERC solar cells. Using a nanosecond laser to cut the finished solar cell in two pieces, no additional power loss is introduced by cutting. The CTM factor of 1.0 determined at the 3 × 6 module is explained using an analytical model describing the series resistance of the module interconnection. Using this model, we estimate for our current PERC cell generation and module process an output power of 275 W for 60 full-size cells and 285 W for 120 halved cells.
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- 2015
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20. Accuracy of Solar Simulator Spectral Determination Using Band-Pass Filtering Method
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Karsten Bothe, Adrienne L. Blum, Cassidy Sainsbury, Harrison Wilterdink, Ronald A. Sinton, Justin Dinger, Martin Wolf, David Hinken, and Weston Dobson
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Spectrometer ,Computer science ,Detector ,Photovoltaic system ,Process (computing) ,Electronic engineering ,Measure (physics) ,Magnitude (mathematics) ,Solar simulator ,Ray - Abstract
CCD spectrometers have become the industry-standard tools for classifying solar simulator light spectrums, but they have drawbacks. A simpler method is to measure the amount of light present in each relevant band defined by the classification standards directly, by filtering the incident light appropriately and measuring its magnitude with a basic detector. This is much less expensive, and also has some other surprising benefits. The difficult aspect of this method is quantifying and correcting for the uncertainties introduced in the process. These will be outlined in detail in order to build confidence in the accuracy of this approach.
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- 2017
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21. Notice of Removal 20.2% Module efficiency on large area with passivated emitter and rear solar cells
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Thorsten Dullweber, Rolf Brendel, Helge Hannebauer, Malte R. Vogt, Marc Köntges, Ingo Ahrens, Robert Witteck, Susanne Blankemeyer, Ulrike Sonntag, Henning Schulte-Huxel, Sarah Spatlich, Hendrik Holst, Karsten Bothe, David Hinken, Ulrike Baumann, Tobias Neubert, and Till Brendemühl
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Materials science ,Notice ,business.industry ,Optoelectronics ,business ,Common emitter - Published
- 2017
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22. Determining the spectral responsivity of solar cells under standard test conditions
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David Hinken, I. Kröger, S. Winter, Rolf Brendel, and Karsten Bothe
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010309 optics ,Physics ,Responsivity ,Spectral responsivity ,Applied Mathematics ,0103 physical sciences ,Analytical chemistry ,Standard test ,Cell analysis ,01 natural sciences ,Instrumentation ,Engineering (miscellaneous) - Abstract
The spectral responsivity alt;iagt;salt;/iagt;alt;subagt;?,STCalt;/subagt;(?) of solar cells is widely used for cell analysis or calibration purposes. According to the IEC60904-8:2014 standard, the reference method for the determination of alt;iagt;salt;/iagt;alt;subagt;?,STCalt;/subagt;(?) is the complete differential spectral responsivity approach. For this approach, the differential spectral responsivity alt;iagt;salt;/iagt;~(?) is measured as a function of wavelength and bias irradiance. To obtain the spectral responsivity alt;iagt;salt;/iagt;alt;subagt;?,STCalt;/subagt;(?) related to standard test conditions the IEC60904-8:2014 standard recommends to integrate 1/alt;iagt;salt;/iagt;~(?) via bias current alt;iagt;Ialt;/iagt;alt;subagt;balt;/subagt; for each wavelength. We show that this integration is wrong. It lacks analytical derivation and provides faulty curves for non-linear solar cells. We proof analytically and by means of simulations that the correct way of calculation is either the integration of alt;iagt;salt;/iagt;~(?) via the bias irradiance alt;iagt;Ealt;/iagt;alt;subagt;balt;/subagt; or the integration of alt;iagt;salt;/iagt;~(?)/alt;iagt;salt;/iagt;~alt;subagt;AMxalt;/subagt; via the bias current alt;iagt;Ialt;/iagt;alt;subagt;balt;/subagt;, with alt;iagt;salt;/iagt;~alt;subagt;AMxalt;/subagt; being the AMx-weighted (e.g. AM1.5G or AM1.5D) differential responsivity. A simulation of the differential spectral responsivity of a strongly non-linear solar cell demonstrates deviations of alt;iagt;salt;/iagt;alt;subagt;?,STCalt;/subagt;(?) up to 30 % for (the wrong) integration of 1/alt;iagt;salt;/iagt;~(?) via alt;iagt;Ialt;/iagt;alt;subagt;balt;/subagt; at some wavelengths, corresponding to a deviation in the short-circuit current of up to 3.0 %.
- Published
- 2019
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23. Impact of contacting geometries on measured fill factors
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Karsten Bothe, Christian Kruse, Martin Wolf, David Hinken, Carsten Schinke, and Rolf Brendel
- Subjects
Solar cells ,Materials science ,Busbar ,020209 energy ,Geometry ,02 engineering and technology ,Molecular physics ,law.invention ,Current-voltage characteristics ,law ,Fill factor ,Solar cell ,0202 electrical engineering, electronic engineering, information engineering ,Resistance variations ,Dewey Decimal Classification::300 | Sozialwissenschaften, Soziologie, Anthropologie::330 | Wirtschaft::333 | Boden- und Energiewirtschaft::333,7 | Natürliche Ressourcen, Energie und Umwelt ,Common emitter ,Busbars ,Different geometry ,Tandem ,business.industry ,Probe position ,Electrical engineering ,Sense (electronics) ,Standard testing ,Measured currents ,Current voltage characteristics ,IV characteristics ,ddc:333.7 ,Probes ,Current (fluid) ,business ,Sensitivity analysis ,Sensitivity (electronics) ,ddc:333,7 ,Characterization of PV ,Tandem configuration - Abstract
The fill factor determined from a measured current-voltage characteristic of a bare solar cell depends on the number and positions of the electrical contacting probes. Nine different geometries for contacting the front side busbars are used to measure the current-voltage (I-V) characteristics of a 5 busbar industrial-type passivated emitter and rear totally diffused (PERT) solar cell under standard testing conditions. The fill factors of the measured I-V characteristics vary from 78.5 % abs to 80.6 % abs . We further measure the contacting resistance of 3 different contacting probes to estimate the sensitivity of measurements with different contacting geometries on random resistance variations. The contacting resistance is 60 mΩ for nine-point probes and 80 mΩ for four- and single-point probes. We determine the magnitude of contacting resistance variations from measurements at different probe positions to be ±30 mΩ. Using this variation, we perform numerical simulations and find a larger sensitivity on random resistance variations for tandem- (pairs of current- and sense probes) compared to triplet (one sense- between two current probes) configurations. The corresponding fill factor deviation is approximately 0.1% abs for tandem configurations when the contacting resistances of up to two current probes are altered. The sensitivity for triplet configurations is negligible.
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- 2017
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24. Validity of Calibrated Photoluminescence Lifetime Measurements of Crystalline Silicon Wafers for Arbitrary Lifetime and Injection Ranges
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Jan Schmidt, Matthias Offer, Sandra Herlufsen, Karsten Bothe, and David Hinken
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Photoluminescence ,Materials science ,Silicon ,Condensed Matter::Other ,business.industry ,chemistry.chemical_element ,Carrier lifetime ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Condensed Matter Physics ,Signal ,Electronic, Optical and Magnetic Materials ,Condensed Matter::Materials Science ,chemistry ,Calibration ,Optoelectronics ,Photoluminescence excitation ,Crystalline silicon ,Electrical and Electronic Engineering ,business ,Luminescence - Abstract
We investigate the validity of calibrated photoluminescence lifetime measurements of crystalline silicon wafers for arbitrary lifetime and injection ranges. Absolute lifetime images are obtained from steady-state photoluminescence measurements by relating the photoluminescence signal to the excess carrier density. Since the luminescence signal is expected to be related to the integral of the depth distribution of the excess carrier density, an adequate calibration of the luminescence signal requires a secondary method which yields the integral of the depth distribution of the excess carrier density in absolute units. In this paper, we investigate the applicability of steady-state photoconductance measurements for the calibration of the photoluminescence signal. We derive a generalized relation linking the photoluminescence signal with the excess carrier density, considering the impact of an inhomogeneous carrier concentration profile. We experimentally verify the impact of the carrier distribution on the photoluminescence calibration by investigating two silicon wafers with different electronic bulk properties. Finally, we propose an iterative correction procedure reducing the deviations due to an inhomogeneous carrier density profile of calibrated photoluminescence-based lifetime measurements significantly.
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- 2013
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25. Collected photocurrent imaging of CIGS solar cells via electro-modulated luminescence under different illumination conditions
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Yael Augarten, David Hinken, Andreas Gerber, Bart E. Pieters, Uwe Rau, and Vito Huhn
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010302 applied physics ,Photocurrent ,Materials science ,Equivalent series resistance ,business.industry ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Copper indium gallium selenide solar cells ,law.invention ,Differential information ,law ,0103 physical sciences ,Solar cell ,Optoelectronics ,Imaging technique ,Thin film ,0210 nano-technology ,business ,Luminescence - Abstract
The collected photocurrent imaging technique measures the total amount of photocurrent that can be collected from every region of a solar cell. The technique is based on the recently introduced differential photocurrent collection efficiency imaging method, which uses luminescence images taken under varying bias conditions and a constant illumination. The differential photocurrent collection efficiency provides information about how the cell or module current reacts to local changes of the generated photocurrent. We explain in detail how certain assumptions and measurements of the photocurrent collection efficiency under different illumination conditions can extend the differential information we obtain from the differential photocurrent collection efficiency to get information about the total amount of photocurrent collected from each specific region of a solar cell. The method was demonstrated on a thin film Cu(In, Ga)Se 2 cell, showing quantitatively how series resistance reduce the collection of photocurrent.
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- 2016
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26. Contacting Interdigitated Back-Contact Solar Cells With Four Busbars for Precise Current–Voltage Measurements Under Standard Testing Conditions
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David Hinken, Karsten Bothe, Fabian Kiefer, Jan Schmidt, Arne Schmidt, Rolf Brendel, Robert Bock, Nils-Peter Harder, Carsten Schinke, Matthias Offer, and Till Brendemühl
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Materials science ,Busbar ,business.industry ,Contact geometry ,Sense (electronics) ,Condensed Matter Physics ,Electronic circuit simulation ,Electronic, Optical and Magnetic Materials ,Optoelectronics ,Fill factor ,Electrical and Electronic Engineering ,business ,Polarity (mutual inductance) ,Voltage drop ,Voltage - Abstract
Increasing the area of interdigitated back-contact (IBC) solar cells featuring a busbar contact geometry requires the use of longer fingers. The finger resistance will, thus, be increased if the thickness of the metallization is kept constant. In order to maintain a thin metallization, it is beneficial to increase the number of busbars per contact. However, using more than one busbar for each polarity implies an asymmetric contact geometry. As a consequence, under operation, the busbars of the same polarity carry different currents. Due to voltage drops over unavoidable electrical resistances, this may lead to significant potential differences between these busbars. Since current–voltage characteristics are usually measured using separate sense contacts for the voltage measurement, the position and number of these contacts may considerably affect the shape of the resulting current–voltage characteristic and, thus, the fill factor. By means of simulations with the circuit simulator LTSpice, we show that a permanent contacting with soldered tabs allows for a correct determination of the fill factor. A chuck used for temporary contacting should feature at least one sense contact per busbar and pin contacting resistances below 30 mΩ in order to keep the fill factor error below 0.5% absolute.
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- 2012
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27. Extended Analysis of Capacitance–Voltage Curves for the Determination of Bulk Dopant Concentrations of Textured Silicon Solar Cells
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Karsten Bothe, M. Schütze, David Hinken, M. B. Koentopp, and Ashley Milsted
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Materials science ,Silicon ,Dopant ,Computer simulation ,business.industry ,Doping ,Analytical chemistry ,chemistry.chemical_element ,Biasing ,Surface finish ,Semiconductor device ,Space charge ,Electronic, Optical and Magnetic Materials ,chemistry ,Optoelectronics ,Electrical and Electronic Engineering ,business - Abstract
Capacitance-Voltage (C- V) measurements are an established method for determining the bulk dopant concentration Nbulk of semiconductor devices. The extraction of Nbulk requires knowledge of the surface area of the space-charge region (SCR). For textured solar cells, this surface area is enlarged, depending on texture and bias voltage. The amount of enlargement is a priori unknown, and there is no simple way of measuring directly it. In this paper, models that were previously proposed in the literature are employed to describe the SCR area. Substantial deficiencies in these models are revealed by comparison with a 3-D numerical simulation of the SCR geometry used as a benchmark. This approach leads to the development of a new analytical model that can properly describe the bias-voltage dependence of the surface area enlargement. C-V measurements over a large bias-voltage range are performed on various solar cells with different textures and resistivities. The new analytical model is employed to correct the measurement data for the influence of surface area enlargement. Thus, Nbulk can be extracted without explicit knowledge of the enlargement. Comparison with four-point probe measurements shows excellent agreement, demonstrating the power of the new method to enable the C-V technique for use in Nbulk determination for textured solar cells.
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- 2011
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28. Determination of the Base-Dopant Concentration of Large-Area Crystalline Silicon Solar Cells
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David Hinken, Ashley Milsted, Achim Schulze, Jörg Isenberg, Karsten Bothe, Matthias Schutze, Robert Bock, Bernhard Fischer, and Matthias Wagner
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Materials science ,Silicon ,Dopant ,Doping ,Analytical chemistry ,chemistry.chemical_element ,Capacitance ,Electronic, Optical and Magnetic Materials ,law.invention ,Monocrystalline silicon ,chemistry ,law ,Solar cell ,Crystalline silicon ,Electrical and Electronic Engineering ,Common emitter - Abstract
The capacitance-voltage (CV) measurement is a precise and fast method to determine base-dopant concentrations of crystalline silicon solar cells. Since available measurement equipment is usually limited in its current output, the application of CV analysis has been limited to small-area solar cells in research laboratories. We present an experimental setup that is capable of measuring CV curves with a current output of up to 2 A. Using this setup, we demonstrate the applicability of CV measurements to large-area industrial solar cells for base-dopant concentrations ranging between 6.0 × 1014 cm-3 and 4.2 t1016 cm-3. An area enhancement factor f quantifying the relation between the macroscopic cell area and the active junction area is determined for alkaline textured mono- and isotextured multicrystalline silicon solar cells. Comparing the base dopant of the CV analysis with four-point probe measurements, we achieve an agreement with an uncertainty of 10%. For alkaline textured monocrystalline silicon solar cells, we demonstrate that the area enhancement factor can be extracted from the ratio of the pyramid base length and emitter thickness.
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- 2010
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29. Detection of the voltage distribution in photovoltaic modules by electroluminescence imaging
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Karsten Bothe, Marc Köntges, David Hinken, Torben Potthoff, and Ulrich Eitner
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Materials science ,Series (mathematics) ,Equivalent series resistance ,Renewable Energy, Sustainability and the Environment ,business.industry ,Photovoltaic system ,Electrical engineering ,Electroluminescence ,Condensed Matter Physics ,Signal ,Electronic, Optical and Magnetic Materials ,law.invention ,Reliability (semiconductor) ,law ,Solar cell ,Electrical and Electronic Engineering ,business ,Voltage - Abstract
We introduce an approach to determine the operating voltage of individual solar cells in photovoltaic (PV) modules by electroluminescence (EL) imaging. The highest EL signal of each solar cell is proportional to its operating voltage. Moreover the sum of all operating voltages equals the externally applied module voltage. Thus the operating voltage of individual solar cells is determined from the measured EL signal. The reliability of this relation is verified by measurements on specially prepared PV modules allowing us to measure the individual operating cell voltage. The experimentally measured cell voltages are deduced with an uncertainty of ±1% from an EL image. Moreover, the operating cell voltages determined from the EL image are used to calculate the module series resistance. Comparing experimentally determined values from the operating cell voltage and the total current flowing supplied to the module with calculated module series resistances using tabulated material and typical solar cell parameters, a very good correspondence is found. Copyright © 2010 John Wiley & Sons, Ltd.
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- 2010
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30. Imaging Techniques for the Analysis of Silicon Wafers and Solar Cells
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David Hinken, K. Ramspeck, Rolf Brendel, and Karsten Bothe
- Subjects
Materials science ,business.industry ,Reverse bias ,Infrared ,Thermography ,Optoelectronics ,Wafer ,Carrier lifetime ,Luminescence ,business ,Image resolution ,Characterization (materials science) - Abstract
For large area devices a spatial analysis of local device and material parameters is essentially important. Imaging techniques allowing a fast and contactless analysis with a high spatial resolution have become a versatile characterization tool during the last decade. We present a comprehensive overview over the existing imaging techniques for the analysis of silicon wafers and solar cells utilizing different spectral ranges of photon emission. Additionally, we report on recent studies of local junction breakdown and the emission of light from solar cells under forward and reverse bias using luminescence imaging and dark lock-in thermography. Finally we present a calibration-free dynamic infrared carrier lifetime mapping (dynamic-ILM) technique, yielding images of the carrier lifetime of multi-crystalline silicon wafers within seconds.
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- 2008
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31. Optimizing the Solar Cell Front Side Metallization and the Cell Interconnection for High Module Power Output
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Henning Schulte-Huxel, Malte R. Vogt, Marc Köntges, David Hinken, Susanne Blankemeyer, Karsten Bothe, Rolf Brendel, Hendrik Holst, and Robert Witteck
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Power gain ,Electric resistance ,Solar cells ,Engineering ,Experimental modules ,020209 energy ,02 engineering and technology ,Electrical and optical properties ,olar modules ,law.invention ,front metallization ,Integrated circuit interconnects ,Electrical resistance and conductance ,Energy(all) ,law ,Solar cell ,0202 electrical engineering, electronic engineering, information engineering ,Metallizing ,ddc:530 ,Recombination loss ,Konferenzschrift ,Common emitter ,cell to module losses ,Equivalent series resistance ,Economic and social effects ,Optical properties ,PERC solar cells ,business.industry ,Electric power system interconnection ,Electrical engineering ,Crystalline materials ,Ray tracing ,021001 nanoscience & nanotechnology ,Power (physics) ,cell interconnection ,Metals ,Optoelectronics ,Ray tracing (graphics) ,Series resistances ,Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik ,Grid metallization ,0210 nano-technology ,business - Abstract
Improving the light trapping in a module results in an increase in the generated current. Consequently, an optimization of the front grid metallization of the cell is required for the best trade-off between series resistance, shading, and recombination losses. For this purpose, we combine ray tracing and electrical solar cell and module calculations that explicitly account for cell and module interactions. Our model bases on experimentally verified input parameters: We determine the electrical and optical properties of the front metal fingers of passivated emitter and rear cells (PERC). We show that the effective optical width of the front metal fingers in the module is significantly reduced by 54%. The optimized simulated module has 120 half-size PERC with 20.2% cell efficiency and has an output power of 295.2 W. This is achieved with an increased number of 120 front metal fingers per cell, four white-colored cell interconnection ribbons (CIR), and an increased cell spacing. Applying these optimized design changes to an experimental module we measure a module power output of 294.8 W and a cell-to-module (CTM) factor of 1.02. Measured and simulated power agree and the deviations in Voc, Isc and FF are less than 0.91%rel. We perform a module power gain analysis for the fabricated module and simulate a potential maximum module power of 374.1 W when including further improvements. German Federal Ministry for Economic Affairs and Energy/0325641
- Published
- 2016
32. Imaging photocurrent collection losses in solar cells
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Bart E. Pieters, Vito Huhn, Andreas Gerber, Uwe Rau, David Hinken, and Yael Augarten
- Subjects
010302 applied physics ,Photocurrent ,Materials science ,Physics and Astronomy (miscellaneous) ,Silicon ,business.industry ,Photoconductivity ,chemistry.chemical_element ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,law.invention ,chemistry ,law ,0103 physical sciences ,Solar cell ,Optoelectronics ,ddc:530 ,Crystalline silicon ,0210 nano-technology ,Luminescence ,business ,Voltage - Abstract
A method is proposed that enables the imaging of the photocurrent collected by a solar cell under arbitrary operating conditions. The method uses a series of luminescence images under varying illumination to derive the total photocurrent collection efficiency at a given voltage bias. The resulting total photocurrent collection image directly relates to the difference between the dark and illuminated current-voltage characteristics of the cell. A crystalline silicon solar cell is used to test the method, and the images of the total photocurrent collection efficiency are used to quantify the influence of a crack on the total collected photocurrent of the solar cell.
- Published
- 2016
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33. Towards more accurate imaging of the local saturation current density in solar cells by using alternative PL evaluation methods
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Jan Bauer, Otwin Breitenstein, David Hinken, and Karsten Bothe
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Maxima and minima ,Optics ,Materials science ,business.industry ,Saturation current ,Thermography ,Spice ,Calibration ,Biasing ,business ,Current density ,Diode - Abstract
We have performed 2-dimensional inhomogeneous solar cell simulations using the circuit-simulation program Spice and obtained photoluminescence (PL), electroluminescence (EL), and dark lock-in thermography (DLIT) images for various illumination and biasing conditions. These images were evaluated by established methods for retrieving images of the saturation current density J01. We found that DLIT delivers blurred but quantitatively correct J01 images, but PL generally delivers too weak local maxima of J01. This is due to the used model of independent diodes, which is too simple to describe the local diode voltage in inhomogeneous cells precisely. In reality lateral balancing currents exist, which are not regarded in established PL evaluation methods. For solving this problem we have checked two alternative PL evaluation methods, which are already published but not established yet. Especially the Laplacian-based method has the potential to overcome this problem. For our simulated images the method yields correct results. However, in spite of some improvements for the determination of the calibration image, our first experimental results obtained by using this method do not agree yet with lock-in thermography based J01 results.
- Published
- 2015
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34. Dynamic photoluminescence lifetime imaging for the characterisation of silicon wafers
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K. Ramspeck, Jens Müller, Sandra Herlufsen, Karsten Bothe, Rolf Brendel, Arne Schmidt, David Hinken, and Jan Schmidt
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Time delay and integration ,Photoluminescence ,Materials science ,business.industry ,Carrier lifetime ,Condensed Matter Physics ,Optics ,General Materials Science ,Wafer ,Crystalline silicon ,Imaging technique ,business ,Luminescence ,Excitation - Abstract
We present a fast and calibration-free carrier lifetime imaging technique based on photoluminescence (PL) measurements using an InGaAs camera for the examination of crystalline silicon wafers. The carrier lifetime is determined from the time dependent luminescence emission after optical excitation. A ratio, including four PL images acquired at different times during the modulated excitation, is calculated and found to depend only on the camera integration time and the effective carrier lifetime. Therefore, the carrier lifetime is unambiguously determined by this ratio without knowing any additional wafer parameter. We demonstrate the applicability of the dynamic PL technique to multicrystalline silicon wafers. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
- Published
- 2010
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35. Photoconductance-calibrated photoluminescence lifetime imaging of crystalline silicon
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David Hinken, Jan Schmidt, Rolf Brendel, Sandra Herlufsen, and Karsten Bothe
- Subjects
Optics ,Charge-carrier density ,Photoluminescence ,Silicon ,chemistry ,business.industry ,Device Camera ,chemistry.chemical_element ,General Materials Science ,Wafer ,Crystalline silicon ,Condensed Matter Physics ,business - Abstract
We use photoluminescence (PL) measurements by a silicon charge-coupled device camera to generate high-resolution lifetime images of multicrystalline silicon wafers. Absolute values of the excess carrier density are determined by calibrating the PL image by means of contactless photoconductance measurements. The photoconductance setup is integrated in the camera-based PL setup and therefore identical measurement conditions are realised. We demonstrate the validity of this method by comparison with microwave-detected photoconductance decay measurements. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
- Published
- 2008
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36. Analyzing the spectral luminescence emission of silicon solar cells and wafers
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Karsten Bothe, David Hinken, Carsten Schinke, Jan Schmidt, and Rolf Brendel
- Subjects
Wavelength ,Materials science ,Photoluminescence ,Silicon ,chemistry ,Attenuation coefficient ,Analytical chemistry ,chemistry.chemical_element ,Free carrier absorption ,Electroluminescence ,Absorption (electromagnetic radiation) ,Luminescence - Abstract
We present an analytical expression for modelling electroluminescence (EL) as well as photoluminescence (PL) data of samples with any combination of planar and arbitrary rough surfaces. The model also accounts for free carrier absorption in highly doped regions of the sample. It is experimentally confirmed by comparison to measured EL and PL spectra of solar cells and wafers featuring different surface geometries. Significant differences in the absorption coefficient data available from literature, which enters the model as tabulated data, are revealed. Using our model, the absorption data by Daub yields the best agreement to the measured luminescence spectra. Moreover, we present a method to determine the rear surface reflectance of samples from the peak wavelength of luminescence spectra.
- Published
- 2013
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37. Quantitative Luminescence Characterization of Crystalline Silicon Solar Cells
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David Hinken and Karsten Bothe
- Subjects
Materials science ,Silicon ,Equivalent series resistance ,business.industry ,Stray light ,chemistry.chemical_element ,law.invention ,Optics ,chemistry ,law ,Solar cell ,Optoelectronics ,Charge carrier ,Crystalline silicon ,business ,Luminescence ,Diode - Abstract
Luminescence imaging has become a standard tool for solar cell analysis within the last decade. In order to understand the potential, as well as the limitations of the numerous luminescence characterization approaches, this work provides both the physical background for modeling the luminescence emission from silicon solar cells as well as a review of series resistance imaging, one of the most prominent applications of luminescence imaging. The first part addresses the measurement setup. A specific focus lies on the suitability of different cameras and the optical filters necessary to prevent the detection of reflected excitation light as well as stray light. Detection conditions with respect to capture time and averaging of images are also discussed. In the second part, we derive a general mathematical description of the spectral luminescence emission. We show that the integral over the product of the depth-dependent minority charge carrier profile and the luminescence photon detection profile fully determines the spectral luminescence emission. Moreover, we show that the luminescence photon detection profile can be obtained from the generation profile of minority charge carriers under illumination, for which well-tested expressions can be found in the literature. Based on the mathematical description, we derive a short- and a long-wavelength approximation corresponding to the spectral sensitivity of silicon and indium–gallium–arsenide detectors, widely used for luminescence measurements. While from the short-wavelength approach the local voltage of a solar cell can be determined, the long-wavelength approach yields the local collection length of the device under test. The final part describes the most prominent application of luminescence imaging: the determination of the local series resistance of wafer-based crystalline silicon solar cells. We review a variety of different approaches introduced in the past. We show that all approaches are based on the same general equation, which is a consequence of the underlying independent diode model. Based on numerical circuit simulations, we study the range of applicability of this simple model. Moreover, the most promising series resistance approaches are applied to various silicon solar cells. Resulting local series resistance and local recombination current images are compared among different methods, as well as to global values extracted from the current–voltage characteristics of the solar cell.
- Published
- 2013
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38. Can luminescence imaging replace lock-in thermography on solar cells and wafers?
- Author
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David Hinken, Wolfram Kwapil, Wilhelm Warta, Martin C. Schubert, Karsten Bothe, Jens Müller, Otwin Breitenstein, and Jan Bauer
- Subjects
Photoluminescence ,Materials science ,Equivalent series resistance ,business.industry ,Thermography ,Optoelectronics ,Wafer ,Carrier lifetime ,Luminescence ,business ,Space charge ,Leakage (electronics) - Abstract
Since 15 years lock-in thermography (LIT) is used to investigate solar cells and modules. While LIT was used at the beginning only for shunt detection, meanwhile special LIT-techniques have been developed to image the minority carrier lifetime, also on wafers, the monochromatic cell efficiency, the local series resistance, the ideality factor, or the physical properties of breakdown sites. A general limitation of LIT is its limited spatial resolution due to thermal blurring. LIT investigation of breakdown sites takes only a fracture of a second, but investigation under forward bias usually takes some minutes. In recent years photoluminescence (PL) and electroluminescence (EL) imaging have become very popular to characterize solar wafers, cells and modules. Just as LIT, luminescence imaging allows to image the local lifetime and local series resistances (with PL even quantitatively), stronger local shunts, breakdown sites, and other faults like cracks. A big advantage of luminescence imaging is that it does not suffer from thermal blurring. Moreover, imaging times in the range of seconds are possible, and the systems are cheaper than LIT systems. The question is: Do we need LIT imaging anymore at all? It will be demonstrated that some important kinds of characterization can be done only by LIT, such as the quantitative measurement of breakdown and leakage currents (especially space charge recombination currents, which are not detectable by EL/PL), ideality factor imaging, the detection of leakage currents below grid lines and bus bars, as well as the quantitative measurement of certain breakdown parameters. Thus, LIT and luminescence imaging are complementing each other. For a complete characterization of solar cells both techniques have to be used in parallel.
- Published
- 2011
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39. Experimental setup for camera-based measurements of electrically and optically stimulated luminescence of silicon solar cells and wafers
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Karsten Bothe, Sandra Herlufsen, Carsten Schinke, David Hinken, Arne Schmidt, and Rolf Brendel
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Carrier injection ,Semiconducting silicon compounds ,Luminescence ,Optically stimulated luminescence ,Light ,Operation conditions ,Gallium arsenide ,Four-quadrant ,chemistry.chemical_compound ,Semiconducting indium ,Silicon solar cells ,Illumination sources ,Luminescence emission ,Instrumentation ,Indium arsenide ,Luminescence imaging ,Electron multipliers ,Noise source ,Signal to noise ratio ,Back-illuminated ,Gallium alloys ,Cameras ,Optoelectronics ,MOS devices ,Experimental setup ,Power supply ,Solar cells ,Materials science ,Photoluminescence ,Silicon ,Complementary metal oxide semiconductors ,Hybrid silicon laser ,chemistry.chemical_element ,Charge carriers ,Silicon wafers ,Semiconductor laser theory ,Optics ,CCD cameras ,Metallic compounds ,Electron multiplier gain ,Radiative recombination ,ddc:530 ,Semiconductor lasers ,business.industry ,Lasers ,Signal to noise ,Coupled devices ,Spatially resolved ,Semiconductor ,chemistry ,Semiconducting silicon ,Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik ,business ,Indium gallium arsenide - Abstract
We report in detail on the luminescence imaging setup developed within the last years in our laboratory. In this setup, the luminescence emission of silicon solar cells or silicon wafers is analyzed quantitatively. Charge carriers are excited electrically (electroluminescence) using a power supply for carrier injection or optically (photoluminescence) using a laser as illumination source. The luminescence emission arising from the radiative recombination of the stimulated charge carriers is measured spatially resolved using a camera. We give details of the various components including cameras, optical filters for electro- and photo-luminescence, the semiconductor laser and the four-quadrant power supply. We compare a silicon charged-coupled device (CCD) camera with a back-illuminated silicon CCD camera comprising an electron multiplier gain and a complementary metal oxide semiconductor indium gallium arsenide camera. For the detection of the luminescence emission of silicon we analyze the dominant noise sources along with the signal-to-noise ratio of all three cameras at different operation conditions. © 2011 American Institute of Physics.
- Published
- 2011
40. Can luminescence imaging replace lock-in thermography on solar cells?
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David Hinken, J. Bauer, Jens Müller, Wolfram Kwapil, Martin C. Schubert, Karsten Bothe, Otwin Breitenstein, Wilhelm Warta, and Publica
- Subjects
Materials science ,Photoluminescence ,Equivalent series resistance ,business.industry ,Messtechnik und Produktionskontrolle ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Silicium-Photovoltaik ,Reverse bias ,Thermography ,Optoelectronics ,Wafer ,Charakterisierung ,Electrical and Electronic Engineering ,business ,Luminescence ,Zellen und Module ,Image resolution ,Charakterisierung von Prozess- und Silicium-Materialien ,Leakage (electronics) ,Solarzellen - Entwicklung und Charakterisierung - Abstract
The purpose of this paper is a detailed comparison of selected luminescence and lock-in thermography (LIT) results on one exemplary sample and the drawing of corresponding conclusions. Our focus is on solar cells, but some investigations on wafers will be discussed as well. The comparison will help to decide which characterization tools are needed to solve technological problems. It will be demonstrated that luminescence imaging may widely replace LIT with respect to the analysis of recombination-active bulk defects, cracks, series resistance, and junction breakdown sites. However, some important investigations can be done only by LIT. LIT allows for a quantitative analysis of different kinds of leakage currents both under forward and under reverse bias, enabling a reliable analysis of local I-V characteristics. It is shown that LIT and luminescence imaging are complementary to each other and should be used in combination.
- Published
- 2011
41. Determination of the collection diffusion length by electroluminescence imaging
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Rolf Brendel, Karsten Bothe, Christian Ulzhöfer, Carsten Schinke, David Hinken, Jan Schmidt, and Ashley Milsted
- Subjects
Materials science ,Silicon ,Light ,Monocrystalline silicon ,Physics::Optics ,chemistry.chemical_element ,Electroluminescence ,Experimental evidence ,law.invention ,Diffusion ,Condensed Matter::Materials Science ,Optics ,Electroluminescence emission ,Energy(all) ,law ,Solar cell ,Silicon solar cells ,ddc:530 ,Relative accuracy ,Crystalline silicon ,Konferenzschrift ,Theory of solar cells ,Collection diffusion length ,business.industry ,collection diffusion length ,Quantum Efficiency measurements ,Crystalline materials ,Multi-crystalline silicon solar cells ,Energy gap ,electroluminescence imaging ,chemistry ,Electroluminescence imaging ,Rear surfaces ,Crystalline silicon solar cells ,Photovoltaic effects ,Polysilicon ,Optoelectronics ,Quantum efficiency ,Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik ,business ,Luminescence ,Diffusion length - Abstract
The electroluminescence emission of crystalline silicon solar cells at near-bandgap wavelengths is investigated. We show that the intensity of the emitted luminescence at near-bandgap wavelengths is directly proportional to the collection diffusion length Lc which is a measure of bulk and rear surface recombination properties and determines the short circuit current of a solar cell illuminated with light of near-bandgap wavelengths. We provide experimental evidence for the determination of Lc by carrying out electroluminescence measurements on a set of 15 specially prepared monocrystalline silicon solar cells with different thicknesses. Moreover, we demonstrate and discuss the applicability of the proposed method to obtain images of the collection diffusion length Lc of multicrystalline silicon solar cells. The values determined by electroluminescence imaging coincide with values obtained from spectrally resolved quantum efficiency measurements with a relative accuracy of 13 %. © 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of SiliconPV 2011.
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- 2011
42. Luminescence emission from forward- and reverse-biased multicrystalline silicon solar cells
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Sandra Herlufsen, Jan-Martin Wagner, Carsten Schinke, J. Bauer, Jan Schmidt, Karsten Bothe, Nikolai Zakharov, Otwin Breitenstein, K. Ramspeck, David Hinken, and Rolf Brendel
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FOS: Computer and information sciences ,Solar cells ,Materials science ,Photoluminescence ,Luminescence ,Silicon ,Light ,Bioinformatics ,General Physics and Astronomy ,chemistry.chemical_element ,Gain information ,Prebreakdown ,Imaging techniques ,Quantum dot solar cell ,Optics ,Solar energy ,Silicon solar cells ,ddc:530 ,Spatial distribution ,Leakage (fluid) ,Plasmonic solar cell ,Industrial emissions ,Forward bias ,Luminescence emission ,Visible light ,Luminescence imaging ,business.industry ,Lockin thermography ,Energy dissipation ,Multi-crystalline silicon solar cells ,Reverse bias ,Remote sensing ,Subband-gap ,Oxygen ,chemistry ,Thermography (imaging) ,Polysilicon ,Optoelectronics ,Light emission ,Specific sites ,Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik ,business ,Microscopic analysis ,Interstitial oxygen concentration ,Visible spectrum - Abstract
We study the emission of light from industrial multicrystalline silicon solar cells under forward and reverse biases. Camera-based luminescence imaging techniques and dark lock-in thermography are used to gain information about the spatial distribution and the energy dissipation at pre-breakdown sites frequently found in multicrystalline silicon solar cells. The pre-breakdown occurs at specific sites and is associated with an increase in temperature and the emission of visible light under reverse bias. Moreover, additional light emission is found in some regions in the subband-gap range between 1400 and 1700 nm under forward bias. Investigations of multicrystalline silicon solar cells with different interstitial oxygen concentrations and with an electron microscopic analysis suggest that the local light emission in these areas is directly related to clusters of oxygen. © 2009 American Institute of Physics.
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- 2009
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43. Determination of the effective diffusion length of silicon solar cells from photoluminescence
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Karsten Bothe, Rolf Brendel, David Hinken, Sandra Herlufsen, and K. Ramspeck
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Theory of solar cells ,Photoluminescence ,Materials science ,business.industry ,General Physics and Astronomy ,Quantum dot solar cell ,law.invention ,Solar cell efficiency ,law ,Solar cell ,Optoelectronics ,Quantum efficiency ,Plasmonic solar cell ,Diffusion (business) ,business - Abstract
We present a method to determine the effective diffusion length Leff of silicon solar cells from photoluminescence (PL) measurements carried out under two different operating conditions. Measuring the photoluminescence emission under open circuit condition (PL-oc), where the solar cell is not contacted at all, and short circuit condition (PL-sc), where the solar cell is held at zero voltage, Leff directly follows from the ratio of the PL-oc and the PL-sc signals. Detailed knowledge about the optical properties of the experimental setup is not necessary since the optical properties cancel out completely. We explain the theoretical background of our method and derive an analytical description for the PL-oc and the PL-sc luminescence emissions. The applicability of our method is demonstrated by the comparison of effective diffusion lengths from PL measurements with values determined from the analysis of internal quantum efficiency measurements.
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- 2009
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44. Series resistance imaging of solar cells by voltage dependent electroluminescence
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Bernhard Fischer, K. Ramspeck, Rolf Brendel, Karsten Bothe, and David Hinken
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Theory of solar cells ,Materials science ,Physics and Astronomy (miscellaneous) ,Equivalent series resistance ,business.industry ,Semiconductor device ,Quantum dot solar cell ,Electroluminescence ,Polymer solar cell ,law.invention ,Monocrystalline silicon ,law ,Solar cell ,Optoelectronics ,business - Abstract
This letter introduces a method based on electroluminescence imaging to determine mappings of the local series resistance of large area semiconductor devices such as solar cells. The method combines the local electroluminescence emission Φi(U) and its derivative Φi′(U) with respect to the applied voltage U. The combined analysis of these two quantities yields the local series resistance Rise and proves the physical validity of the used current transport model and thus the physical relevance of the determined Rise value. The method is verified on a monocrystalline silicon solar cell with local shunts and local series resistance problems.
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- 2007
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45. Recombination current and series resistance imaging of solar cells by combined luminescence and lock-in thermography
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K. Ramspeck, David Hinken, Karsten Bothe, Jan Schmidt, Rolf Brendel, and Bernhard Fischer
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Materials science ,Physics and Astronomy (miscellaneous) ,Silicon ,Pixel ,Equivalent series resistance ,business.industry ,chemistry.chemical_element ,Electroluminescence ,law.invention ,Optics ,chemistry ,Electrical resistance and conductance ,law ,Solar cell ,Thermography ,Optoelectronics ,Crystalline silicon ,business - Abstract
We perform recombination current and series resistance imaging on large-area crystalline silicon solar cells using a combined analysis of camera-based dark lock-in thermography (DLIT) and electroluminescence (EL) imaging. The solar cells are imaged both by DLIT and EL under identical operating conditions. The quantitative analysis of the DLIT measurement produces an image of the local heating power and the EL picture results in an image of the local cell voltage. Combining the two images pixel by pixel allows us to calculate images of the local recombination current and the local series resistance of the solar cell.
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- 2007
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46. Impact of Ag Pads on the Series Resistance of PERC Solar Cells
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Henning Schulte-Huxel, David Hinken, Robert Witteck, Karsten Bothe, Rolf Brendel, Paula van Laak, and Till Brendemühl
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Electric resistance ,Solar cells ,Finite element method ,Silicon ,Materials science ,Silver ,Finite element simulations ,chemistry.chemical_element ,laser fiered contacts ,02 engineering and technology ,Charge carriers ,01 natural sciences ,law.invention ,Electrical resistance and conductance ,Energy(all) ,law ,0103 physical sciences ,Solar cell ,module interconnection ,ddc:530 ,Screen printing ,Majority charge carriers ,Konferenzschrift ,Common emitter ,010302 applied physics ,Module integration ,Busbars ,Equivalent series resistance ,PERC solar cells ,business.industry ,Electrical engineering ,Crystalline materials ,Interconnector ,021001 nanoscience & nanotechnology ,Laser beam welding ,chemistry ,Charge carrier generation ,laser welding ,Optoelectronics ,Charge carrier ,Series resistances ,Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik ,0210 nano-technology ,business ,Dielectric layer - Abstract
Screen-printed passivated emitter and rear cells (PERC) require Ag pads on the rear side to enable solderable connections for module integration. These Ag pads are separated from the silicon by a dielectric layer to avoid recombination of minority charge carriers. The drawback of this configuration is an elongated transport path for the majority charge carriers generated above the pads. This results in an increase in series resistance. The strength of this effect depends on charge carrier generation above the Ag pads that critically depends on shading of the cell's front side. Ag pads are usually wider than the busbars or the interconnector ribbons and thus are only partially shaded. We build PERC test structures with various rear side configurations of Ag and Al screen printing as well as with and without laser contact openings (LCO). Using experiments and finite element simulations we investigate the impact of shading the Ag pads by the busbars and other means. While fully shaded regions do not increase the lumped solar cell's series resistance, unshaded Ag pads lead to an increase of about 37%. German Federal Ministry for Economic Affairs and Energy/0325641
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