Veröffentlichungen
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J. Schmidt, R. Peibst, and R. Brendel Surface passivation of crystalline silicon solar cells: Present and future Artikel Solar Energy Materials and Solar Cells 187 , 39-54 (2018), ISSN: 0927-0248. Abstract | Links | BibTeX | Schlagwörter: Carrier-selective contacts, silicon solar cells, surface passivation @article{Schmidt2018b,
title = {Surface passivation of crystalline silicon solar cells: Present and future}, author = {J Schmidt and R Peibst and R Brendel}, doi = {10.1016/j.solmat.2018.06.047}, issn = {0927-0248}, year = {2018}, date = {2018-12-01}, journal = {Solar Energy Materials and Solar Cells}, volume = {187}, pages = {39-54}, abstract = {In the first part of this paper, we review the developments which led to the present state-of-the-art in the surface passivation of today's industrially predominant dopant-diffused crystalline silicon (c-Si) solar cells, based on dielectric layers such as silicon oxide, silicon nitride, aluminum oxide and stacks thereof. In the second part of this review, we focus on the future developments in the field of c-Si solar cells based on carrier-selective passivation layers. Whereas the dielectric layers are insulating and are hence applied only for passivating the non-contacted areas of the silicon surface, the carrier-selective passivation layers are intended to provide an effective passivation of non-contacted as well as contacted areas of a c-Si solar cell, thereby increasing the efficiency potential of c-Si solar cells significantly. Due to the fact that the carrier-selective layers are implemented in a contact, besides the good passivation properties for minorities, these layers must also provide a good majority carrier transport, i.e. they have to provide a low contact resistance. Both properties, i.e. suppression of minority-carrier recombination as well as good majority-carrier transport, define the selectivity of the carrier-selective contact, which is an important figure of merit for the assessment and comparison of different types of carrier-selective contacts. One very promising type of carrier-selective passivation layer is based on heavily doped polycrystalline silicon layers deposited on a thin silicon oxide layer, the latter providing the excellent passivation while enabling efficient majority-carrier transport via pin-holes and/or tunneling. Moreover, we discuss metal oxides and conductive polymers, which have only recently been applied to c-Si photovoltaics, but seem to have a promising potential as low-cost selective contact materials. We finally compare combinations of the various options of carrier-selective layers concerning their combined selectivities and efficiency potentials.}, keywords = {Carrier-selective contacts, silicon solar cells, surface passivation}, pubstate = {published}, tppubtype = {article} } In the first part of this paper, we review the developments which led to the present state-of-the-art in the surface passivation of today's industrially predominant dopant-diffused crystalline silicon (c-Si) solar cells, based on dielectric layers such as silicon oxide, silicon nitride, aluminum oxide and stacks thereof. In the second part of this review, we focus on the future developments in the field of c-Si solar cells based on carrier-selective passivation layers. Whereas the dielectric layers are insulating and are hence applied only for passivating the non-contacted areas of the silicon surface, the carrier-selective passivation layers are intended to provide an effective passivation of non-contacted as well as contacted areas of a c-Si solar cell, thereby increasing the efficiency potential of c-Si solar cells significantly. Due to the fact that the carrier-selective layers are implemented in a contact, besides the good passivation properties for minorities, these layers must also provide a good majority carrier transport, i.e. they have to provide a low contact resistance. Both properties, i.e. suppression of minority-carrier recombination as well as good majority-carrier transport, define the selectivity of the carrier-selective contact, which is an important figure of merit for the assessment and comparison of different types of carrier-selective contacts. One very promising type of carrier-selective passivation layer is based on heavily doped polycrystalline silicon layers deposited on a thin silicon oxide layer, the latter providing the excellent passivation while enabling efficient majority-carrier transport via pin-holes and/or tunneling. Moreover, we discuss metal oxides and conductive polymers, which have only recently been applied to c-Si photovoltaics, but seem to have a promising potential as low-cost selective contact materials. We finally compare combinations of the various options of carrier-selective layers concerning their combined selectivities and efficiency potentials.
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B. A. Veith-Wolf, S. Schäfer, R. Brendel, and J. Schmidt Solar Energy Materials and Solar Cells 186 , 194-199 (2018), ISSN: 0927-0248. Abstract | Links | BibTeX | Schlagwörter: Aluminum oxide, Auger recombination, charge carrier lifetime, Intrinsic lifetime, silicon, surface passivation @article{Veith-Wolf2018b,
title = {Reassessment of intrinsic lifetime limit in n-type crystalline silicon and implication on maximum solar cell efficiency}, author = {B A Veith-Wolf and S Schäfer and R Brendel and J Schmidt}, doi = {10.1016/j.solmat.2018.06.029}, issn = {0927-0248}, year = {2018}, date = {2018-11-01}, journal = {Solar Energy Materials and Solar Cells}, volume = {186}, pages = {194-199}, abstract = {Unusually high carrier lifetimes are measured by photoconductance decay on n-type Czochralski-grown silicon wafers of different doping concentrations, passivated using plasma-assisted atomic-layer-deposited aluminum oxide (Al2O3) on both wafer surfaces. The measured effective lifetimes significantly exceed the intrinsic lifetime limit previously reported in the literature. Several prerequisites have to be fulfilled to allow the measurement of such high lifetimes on Al2O3-passivated n-type silicon wafers: (i) large-area wafers are required to minimize the impact of edge recombination via the Al2O3-charge-induced inversion layer, (ii) an exceptionally homogeneous Al2O3 surface passivation is required, and (iii) very thick silicon wafers are needed. Based on our lifetime measurements on n-type silicon wafers of different doping concentrations, we introduce a new parameterization of the intrinsic lifetime for n-type crystalline silicon. This new parameterization has implications concerning the maximum reachable efficiency of n-type silicon solar cells, which is larger than assumed before.}, keywords = {Aluminum oxide, Auger recombination, charge carrier lifetime, Intrinsic lifetime, silicon, surface passivation}, pubstate = {published}, tppubtype = {article} } Unusually high carrier lifetimes are measured by photoconductance decay on n-type Czochralski-grown silicon wafers of different doping concentrations, passivated using plasma-assisted atomic-layer-deposited aluminum oxide (Al2O3) on both wafer surfaces. The measured effective lifetimes significantly exceed the intrinsic lifetime limit previously reported in the literature. Several prerequisites have to be fulfilled to allow the measurement of such high lifetimes on Al2O3-passivated n-type silicon wafers: (i) large-area wafers are required to minimize the impact of edge recombination via the Al2O3-charge-induced inversion layer, (ii) an exceptionally homogeneous Al2O3 surface passivation is required, and (iii) very thick silicon wafers are needed. Based on our lifetime measurements on n-type silicon wafers of different doping concentrations, we introduce a new parameterization of the intrinsic lifetime for n-type crystalline silicon. This new parameterization has implications concerning the maximum reachable efficiency of n-type silicon solar cells, which is larger than assumed before.
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F. Haase, C. Hollemann, S. Schäfer, A. Merkle, M. Rienäcker, J. Krügener, R. Brendel, and R. Peibst Solar Energy Materials and Solar Cells 186 , 184-193 (2018), ISSN: 0927-0248. Abstract | Links | BibTeX | Schlagwörter: Back-contact solar cell, Laser, passivating contacts, POLO @article{Haase2018c,
title = {Laser contact openings for local poly-Si-metal contacts enabling 26.1%-efficient POLO-IBC solar cells}, author = {F Haase and C Hollemann and S Schäfer and A Merkle and M Rienäcker and J Krügener and R Brendel and R Peibst}, doi = {10.1016/j.solmat.2018.06.020}, issn = {0927-0248}, year = {2018}, date = {2018-11-01}, journal = {Solar Energy Materials and Solar Cells}, volume = {186}, pages = {184-193}, abstract = {We demonstrate damage-free laser contact openings in silicon oxide layers on polycrystalline silicon on oxide (POLO) passivating contacts. A pulsed UV-laser evaporates the upper part of the polycrystalline silicon layer, lifting off the silicon oxide layer on top. On n-type POLO (and p-type POLO, respectively) samples a saturation current density of 2 fA cm−2 (6 fA cm−2) and an implied open-circuit voltage of 733 mV (727 mV) are achieved with a laser contact opening area fraction of 12.3% (8.7%). The application of this ablation process in an interdigitated back contact solar cell leads to an independently confirmed power conversion efficiency of 26.1%. The excellent contact quality of the laser contact openings is proven by the low series resistance of 0.1 Ω cm2 on the solar cell with a contact area of only 3%.}, keywords = {Back-contact solar cell, Laser, passivating contacts, POLO}, pubstate = {published}, tppubtype = {article} } We demonstrate damage-free laser contact openings in silicon oxide layers on polycrystalline silicon on oxide (POLO) passivating contacts. A pulsed UV-laser evaporates the upper part of the polycrystalline silicon layer, lifting off the silicon oxide layer on top. On n-type POLO (and p-type POLO, respectively) samples a saturation current density of 2 fA cm−2 (6 fA cm−2) and an implied open-circuit voltage of 733 mV (727 mV) are achieved with a laser contact opening area fraction of 12.3% (8.7%). The application of this ablation process in an interdigitated back contact solar cell leads to an independently confirmed power conversion efficiency of 26.1%. The excellent contact quality of the laser contact openings is proven by the low series resistance of 0.1 Ω cm2 on the solar cell with a contact area of only 3%.
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M. Köntges, H. Schulte-Huxel, S. Blankemeyer, M. R. Vogt, H. Holst, and R. Reineke-Koch Measuring the light recovery factor of backsheets in photovoltaic modules Artikel Solar Energy Materials and Solar Cells 186 , 175-183 (2018), ISSN: 0927-0248. Abstract | Links | BibTeX | Schlagwörter: Backsheet, light harvesting, Light Trapping, Module efficiency, PV Module @article{Köntges2018b,
title = {Measuring the light recovery factor of backsheets in photovoltaic modules}, author = {M Köntges and H Schulte-Huxel and S Blankemeyer and M R Vogt and H Holst and R Reineke-Koch}, doi = {10.1016/j.solmat.2018.06.028}, issn = {0927-0248}, year = {2018}, date = {2018-11-01}, journal = {Solar Energy Materials and Solar Cells}, volume = {186}, pages = {175-183}, abstract = {We measure the short circuit current improvement of various commercial backsheets for passivated emitter and rear solar cells (PERC) in photovoltaic (PV) modules. We quantify this improvement by a light recovery factor k defined as the share of the light reflected by the backsheet around the cell in a PV module laminate, which is converted into electrical current by the solar cells in the module relative to a reference rear surface. The presented measurement method allows measuring the light recovery factor as function of the incident light beam angle, which are important for the calculation of the yield analysis in the field. Simulations of the recovery factor with the optical ray tracing program DIADALOS are performed in order to support the interpretation of the results. For measuring the absolute light recovery probability of a backsheet one should use a reference backsheet with an absorbance of close to 100% to avoid systematic reflection errors especially for high incident light beam angles > 50°. The ranking of various recovery factors are compared to the ranking measured by reflectance measurements defined in standard IEC 62788-2 Ed.1 for backsheets. The standard shows a substantial deviation between the ranking of recovery factor and the reflectance which can be corrected by using an adapted definition for the reflectance measurement method.}, keywords = {Backsheet, light harvesting, Light Trapping, Module efficiency, PV Module}, pubstate = {published}, tppubtype = {article} } We measure the short circuit current improvement of various commercial backsheets for passivated emitter and rear solar cells (PERC) in photovoltaic (PV) modules. We quantify this improvement by a light recovery factor k defined as the share of the light reflected by the backsheet around the cell in a PV module laminate, which is converted into electrical current by the solar cells in the module relative to a reference rear surface. The presented measurement method allows measuring the light recovery factor as function of the incident light beam angle, which are important for the calculation of the yield analysis in the field. Simulations of the recovery factor with the optical ray tracing program DIADALOS are performed in order to support the interpretation of the results. For measuring the absolute light recovery probability of a backsheet one should use a reference backsheet with an absorbance of close to 100% to avoid systematic reflection errors especially for high incident light beam angles > 50°. The ranking of various recovery factors are compared to the ranking measured by reflectance measurements defined in standard IEC 62788-2 Ed.1 for backsheets. The standard shows a substantial deviation between the ranking of recovery factor and the reflectance which can be corrected by using an adapted definition for the reflectance measurement method.
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N. Folchert, M. Rienäcker, A. A. Yeo, B. Min, R. Peibst, and R. Brendel Temperature-dependent contact resistance of carrier selective Poly-Si on oxide junctions Artikel Solar Energy Materials and Solar Cells 185 , 425-430 (2018), ISSN: 0927-0248. Abstract | Links | BibTeX | Schlagwörter: Contact resistance, passivating contacts, Pinhole transport, POLO, Poly-Si, selective contacts, Transfer-length-method, Tunneling @article{Folchert2018b,
title = {Temperature-dependent contact resistance of carrier selective Poly-Si on oxide junctions}, author = {N Folchert and M Rienäcker and A A Yeo and B Min and R Peibst and R Brendel}, doi = {10.1016/j.solmat.2018.05.046}, issn = {0927-0248}, year = {2018}, date = {2018-10-01}, journal = {Solar Energy Materials and Solar Cells}, volume = {185}, pages = {425-430}, abstract = {Abstract Carrier selective junctions using a poly-silicon/ silicon oxide stack on crystalline silicon feature low recombination currents \{J0\} whilst allowing for low contact resistivity ρ C . We describe the limiting current transport mechanism as a combination of homogeneous tunneling through the interfacial silicon oxide layer and transport through pinholes where the interfacial silicon oxide layer is locally disrupted. We present an experimental method and its theoretical basis to discriminate between homogenous tunneling and local pinhole transport mechanisms on n + /n or p + /p junctions by measuring the temperature-dependent contact resistance. Theory predicts opposing trends for the temperature dependencies of tunneling and pinhole transport. This allows identifying the dominant transport path. For the contact resistance of two differently prepared poly-Si/ silicon oxide/ c-Si junctions we either find clear pinhole-type or clear tunneling-type temperature dependence. Pinhole transport contributes more than 94 % to the total current for the sample with a 2.1 nm-thick interfacial silicon oxide that we anneal at a temperature of 1050 °C to achieve highest selectivity. In contrast pinhole transport contributes less than 35 % to the total current for the sample with a 1.7 nm-thick silicon oxide that we annealed at only 700 °C in order to avoid pinholes.}, keywords = {Contact resistance, passivating contacts, Pinhole transport, POLO, Poly-Si, selective contacts, Transfer-length-method, Tunneling}, pubstate = {published}, tppubtype = {article} } Abstract Carrier selective junctions using a poly-silicon/ silicon oxide stack on crystalline silicon feature low recombination currents {J0} whilst allowing for low contact resistivity ρ C . We describe the limiting current transport mechanism as a combination of homogeneous tunneling through the interfacial silicon oxide layer and transport through pinholes where the interfacial silicon oxide layer is locally disrupted. We present an experimental method and its theoretical basis to discriminate between homogenous tunneling and local pinhole transport mechanisms on n + /n or p + /p junctions by measuring the temperature-dependent contact resistance. Theory predicts opposing trends for the temperature dependencies of tunneling and pinhole transport. This allows identifying the dominant transport path. For the contact resistance of two differently prepared poly-Si/ silicon oxide/ c-Si junctions we either find clear pinhole-type or clear tunneling-type temperature dependence. Pinhole transport contributes more than 94 % to the total current for the sample with a 2.1 nm-thick interfacial silicon oxide that we anneal at a temperature of 1050 °C to achieve highest selectivity. In contrast pinhole transport contributes less than 35 % to the total current for the sample with a 1.7 nm-thick silicon oxide that we annealed at only 700 °C in order to avoid pinholes.
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L. Helmich, D. C. Walter, D. Bredemeier, R. Falster, V. V. Voronkov, and J. Schmidt In-situ characterization of electron-assisted regeneration of Cz-Si solar cells Artikel Solar Energy Materials and Solar Cells 185 , 283-286 (2018), ISSN: 0927-0248. Abstract | Links | BibTeX | Schlagwörter: boron-oxygen defect, Czochralski-grown silicon, LID, regeneration, solar cell @article{Helmich2018b,
title = {In-situ characterization of electron-assisted regeneration of Cz-Si solar cells}, author = {L Helmich and D C Walter and D Bredemeier and R Falster and V V Voronkov and J Schmidt}, doi = {10.1016/j.solmat.2018.05.023}, issn = {0927-0248}, year = {2018}, date = {2018-10-01}, journal = {Solar Energy Materials and Solar Cells}, volume = {185}, pages = {283-286}, abstract = {Abstract We examine the regeneration kinetics of passivated emitter and rear solar cells (PERCs) fabricated on boron-doped p-type Czochralski-grown silicon wafers in darkness by electron injection via application of a forward bias voltage at elevated temperature (140 °C) in order to discriminate between electronic and photonic effects. Based on these dark regeneration experiments, we address the existing inconsistency regarding the measured linear dependence of the regeneration rate constant on the excess carrier density. Using the method of dark regeneration by current injection into the solar cell, we are able to measure the total recombination current of the solar cell at the actual regeneration temperature under applied voltage, i.e., at the physically relevant regeneration conditions. The direct comparison of the regeneration rate constant as a function of electronically injected carrier concentration in the dark and the regeneration rate constant during illumination clearly shows that the regeneration is a purely electronically stimulated effect and that photons are not directly involved.}, keywords = {boron-oxygen defect, Czochralski-grown silicon, LID, regeneration, solar cell}, pubstate = {published}, tppubtype = {article} } Abstract We examine the regeneration kinetics of passivated emitter and rear solar cells (PERCs) fabricated on boron-doped p-type Czochralski-grown silicon wafers in darkness by electron injection via application of a forward bias voltage at elevated temperature (140 °C) in order to discriminate between electronic and photonic effects. Based on these dark regeneration experiments, we address the existing inconsistency regarding the measured linear dependence of the regeneration rate constant on the excess carrier density. Using the method of dark regeneration by current injection into the solar cell, we are able to measure the total recombination current of the solar cell at the actual regeneration temperature under applied voltage, i.e., at the physically relevant regeneration conditions. The direct comparison of the regeneration rate constant as a function of electronically injected carrier concentration in the dark and the regeneration rate constant during illumination clearly shows that the regeneration is a purely electronically stimulated effect and that photons are not directly involved.
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F. Haase, J. Käsewieter, S. R. Nabavi, E. Jansen, R. Rolfes, and M. Köntges Fracture Probability, Crack Patterns, and Crack Widths of Multicrystalline Silicon Solar Cells in PV Modules During Mechanical Loading Artikel Forthcoming IEEE Journal of Photovoltaics 1-15 Forthcoming, ISSN: 2156-3381. Abstract | Links | BibTeX | Schlagwörter: Crack, mechanical loading, photovoltaic (PV) module, Silicon solar cell @article{Haase2018c,
title = {Fracture Probability, Crack Patterns, and Crack Widths of Multicrystalline Silicon Solar Cells in PV Modules During Mechanical Loading}, author = {F Haase and J Käsewieter and S R Nabavi and E Jansen and R Rolfes and M Köntges}, doi = {10.1109/JPHOTOV.2018.2871338}, issn = {2156-3381}, year = {2018}, date = {2018-10-01}, journal = {IEEE Journal of Photovoltaics}, pages = {1-15}, abstract = {We experimentally analyze the position and opening behavior of cracks in multicrystalline silicon solar cells laminated in standard-sized frameless modules during mechanical loading in a 4-line-bending setup. The results of the experiment are reproduced by simulations for a standard module. These simulations open the opportunity to simulate also complex load situations. Cell interconnect ribbons have big influence to which critically extended module can be bended until a crack appears. Modules with cell interconnect ribbons that are parallel to the bending axis can be bended four times less until cell cracking than modules with cell interconnect ribbons oriented perpendicular to the bending axis and two times less compared with a module without cell interconnect ribbons. Small edge cracks parallel to the bending axis and cross cracks at the busbar decrease the critical bending in the module by a factor of four compared to small edge cracks perpendicular to the bending axis and crack-free cells. The presence of the backsheet decreases the crack width during mechanical loading by 30% compared to a module without a backsheet. In the standard module, the crack width of a single crack is 3.4 μm at loads comparable to the IEC 61215 5400 Pa test.}, keywords = {Crack, mechanical loading, photovoltaic (PV) module, Silicon solar cell}, pubstate = {forthcoming}, tppubtype = {article} } We experimentally analyze the position and opening behavior of cracks in multicrystalline silicon solar cells laminated in standard-sized frameless modules during mechanical loading in a 4-line-bending setup. The results of the experiment are reproduced by simulations for a standard module. These simulations open the opportunity to simulate also complex load situations. Cell interconnect ribbons have big influence to which critically extended module can be bended until a crack appears. Modules with cell interconnect ribbons that are parallel to the bending axis can be bended four times less until cell cracking than modules with cell interconnect ribbons oriented perpendicular to the bending axis and two times less compared with a module without cell interconnect ribbons. Small edge cracks parallel to the bending axis and cross cracks at the busbar decrease the critical bending in the module by a factor of four compared to small edge cracks perpendicular to the bending axis and crack-free cells. The presence of the backsheet decreases the crack width during mechanical loading by 30% compared to a module without a backsheet. In the standard module, the crack width of a single crack is 3.4 μm at loads comparable to the IEC 61215 5400 Pa test.
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V. Titova, and J. Schmidt Implementation of full-area-deposited electron-selective TiOx layers into silicon solar cells Inproceedings Forthcoming WIP (Hrsg.): Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition, Brussels, Belgium, Forthcoming. @inproceedings{Titova2018b,
title = {Implementation of full-area-deposited electron-selective TiOx layers into silicon solar cells}, author = {V Titova and J Schmidt}, editor = {WIP}, year = {2018}, date = {2018-09-24}, booktitle = {Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition}, address = {Brussels, Belgium}, keywords = {TiO}, pubstate = {forthcoming}, tppubtype = {inproceedings} } |
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A. Merkle, B. Min, R. Brendel, R. Peibst, S. Seren, H. Knauss, R. Nissler, J. Steffens, and B. Terheiden Atmospheric Pressure Chemical Vapor Deposition of in-Situ Doped Amorphous Silicon Layers for Passivating Contacts Inproceedings Forthcoming WIP (Hrsg.): Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition, Brussels, Belgium, Forthcoming. @inproceedings{Merkle2018,
title = {Atmospheric Pressure Chemical Vapor Deposition of in-Situ Doped Amorphous Silicon Layers for Passivating Contacts}, author = {A Merkle and B Min and R Brendel and R Peibst and S Seren and H Knauss and R Nissler and J Steffens and B Terheiden}, editor = {WIP}, year = {2018}, date = {2018-09-24}, booktitle = {Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition}, journal = {Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition}, address = {Brussels, Belgium}, keywords = {APCVD}, pubstate = {forthcoming}, tppubtype = {inproceedings} } |
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C. N. Kruse, K. Bothe, B. Lim, T. Dullweber, and R. Brendel Synergistic Efficiency Gain Analyses for the Photovoltaic Community: An Easy to Use SEGA Simulation Tool for Silicon Solar Cells Inproceedings Forthcoming WIP (Hrsg.): Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition, Brussels, Belgium, Forthcoming. @inproceedings{Kruse2018b,
title = {Synergistic Efficiency Gain Analyses for the Photovoltaic Community: An Easy to Use SEGA Simulation Tool for Silicon Solar Cells}, author = {C N Kruse and K Bothe and B Lim and T Dullweber and R Brendel}, editor = {WIP}, year = {2018}, date = {2018-09-24}, booktitle = {Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition}, address = {Brussels, Belgium}, keywords = {SEGA}, pubstate = {forthcoming}, tppubtype = {inproceedings} } |
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R. Brendel, C. Kruse, A. Merkle, and R. Peibst Screening Selective Contact Material Combinations for Novel Crystalline Si Cell Structures Inproceedings Forthcoming WIP (Hrsg.): Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition, Brussels, Belgium, Forthcoming. BibTeX | Schlagwörter: selective contact @inproceedings{Brendel2018,
title = {Screening Selective Contact Material Combinations for Novel Crystalline Si Cell Structures}, author = {R Brendel and C Kruse and A Merkle and R Peibst}, editor = {WIP}, year = {2018}, date = {2018-09-24}, booktitle = {Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition}, address = {Brussels, Belgium}, keywords = {selective contact}, pubstate = {forthcoming}, tppubtype = {inproceedings} } |
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M. R. Vogt, T. Gewohn, K. Bothe, and R. Brendel Impact of Using Spectrally Resolved Ground Albedo Data for Performance Simulations of Bifacial Modules Inproceedings Forthcoming WIP (Hrsg.): Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition, Brussels, Belgium, Forthcoming. @inproceedings{Vogt2018,
title = {Impact of Using Spectrally Resolved Ground Albedo Data for Performance Simulations of Bifacial Modules}, author = {M R Vogt and T Gewohn and K Bothe and R Brendel}, editor = {WIP}, year = {2018}, date = {2018-09-24}, booktitle = {Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition}, address = {Brussels, Belgium}, keywords = {albedo}, pubstate = {forthcoming}, tppubtype = {inproceedings} } |
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D. Bredemeier, D. C. Walter, and J. Schmidt Production Compatible Remedy Against LeTID in High-Performance Multicrystalline Silicon Solar Cells Inproceedings Forthcoming WIP (Hrsg.): Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition, Brussels, Belgium, Forthcoming. @inproceedings{Bredemeier2018c,
title = {Production Compatible Remedy Against LeTID in High-Performance Multicrystalline Silicon Solar Cells}, author = {D Bredemeier and D C Walter and J Schmidt}, editor = {WIP}, year = {2018}, date = {2018-09-24}, booktitle = {Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition}, address = {Brussels, Belgium}, keywords = {LeTID}, pubstate = {forthcoming}, tppubtype = {inproceedings} } |
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D. C. Walter, L. Helmich, D. Bredemeier, J. Schmidt, R. Falster, and V. V. Voronkov Lifetime Evolution during Regeneration in Boron-Doped Czochralski-Silicon Inproceedings Forthcoming WIP (Hrsg.): Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition, Brussels, Belgium, Forthcoming. @inproceedings{Walter2018,
title = {Lifetime Evolution during Regeneration in Boron-Doped Czochralski-Silicon}, author = {D C Walter and L Helmich and D Bredemeier and J Schmidt and R Falster and V V Voronkov}, editor = {WIP}, year = {2018}, date = {2018-09-24}, booktitle = {Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition}, address = {Brussels, Belgium}, keywords = {LID}, pubstate = {forthcoming}, tppubtype = {inproceedings} } |
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B. Min, T. Wietler, S. Bordihn, R. Peibst, T. Desrues, P. Carroy, J. Jourdan, M. Hermle, F. Feldmann, J. Bartsch, C. Allebé, L. Ding, J. Horzel, A. Lachowicz, A. Ingenito, F-J. Haug, E. Schneiderlöchner, V. Linss, K. Lüdemann, A. Campa, M. Bokalic, M. Topic, M. Zwegers, B. Hartlin, B. Field, B. Bénédicte, Z. Adam, J. Penaud, S. Filonovich, E. Marcon, J. Chupin, and F. Tamini Status of the EU H2020 Disc Project: European Collaboration in Research and Development of High Efficient Double Side Contacted Cells with Innovative Carrier-Selective Contacts Inproceedings Forthcoming WIP (Hrsg.): Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition, Brussels, Belgium, Forthcoming. BibTeX | Schlagwörter: Horizon2020 @inproceedings{Min2018b,
title = {Status of the EU H2020 Disc Project: European Collaboration in Research and Development of High Efficient Double Side Contacted Cells with Innovative Carrier-Selective Contacts}, author = {B Min and T Wietler and S Bordihn and R Peibst and T Desrues and P Carroy and J Jourdan and M Hermle and F Feldmann and J Bartsch and C Allebé and L Ding and J Horzel and A Lachowicz and A Ingenito and F-J Haug and E Schneiderlöchner and V Linss and K Lüdemann and A Campa and M Bokalic and M Topic and M Zwegers and B Hartlin and B Field and B Bénédicte and Z Adam and J Penaud and S Filonovich and E Marcon and J Chupin and F Tamini}, editor = {WIP}, year = {2018}, date = {2018-09-24}, booktitle = {Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition}, address = {Brussels, Belgium}, keywords = {Horizon2020}, pubstate = {forthcoming}, tppubtype = {inproceedings} } |
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B. Lim, A. Merkle, R. Peibst, T. Dullweber, Y. Wang, and R. Zhou LID - Free PERC+ Solar Cells with Stable Efficiencies Up to 22.1% Inproceedings Forthcoming WIP (Hrsg.): Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition, Brussels, Belgium, Forthcoming. @inproceedings{Lim2018,
title = {LID - Free PERC+ Solar Cells with Stable Efficiencies Up to 22.1%}, author = {B Lim and A Merkle and R Peibst and T Dullweber and Y Wang and R Zhou}, editor = {WIP}, year = {2018}, date = {2018-09-24}, booktitle = {Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition}, publisher = {Brussels, Belgium}, keywords = {LID}, pubstate = {forthcoming}, tppubtype = {inproceedings} } |
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C. Klamt, M. Rienäcker, F. Haase, N. Folchert, R. Brendel, R. Peibst, V. Krausse, and J. Krügener Intrinsic Poly-Crystalline Silicon Region in between the p+ and n+ POLO Contacts of an 26.1%-Efficient IBC Solar Cell Inproceedings Forthcoming WIP (Hrsg.): Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition, Brussels, Belgium, Forthcoming. @inproceedings{Klamt2018,
title = { Intrinsic Poly-Crystalline Silicon Region in between the p+ and n+ POLO Contacts of an 26.1%-Efficient IBC Solar Cell}, author = {C Klamt and M Rienäcker and F Haase and N Folchert and R Brendel and R Peibst and V Krausse and J Krügener}, editor = {WIP}, year = {2018}, date = {2018-09-24}, booktitle = {Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition}, address = {Brussels, Belgium}, keywords = {POLO}, pubstate = {forthcoming}, tppubtype = {inproceedings} } |
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J. A. Tsanakas, U. Jahn, M. Herz, M. Köntges, D. Parlevliet, M. Paggi, J. S. Stein, K. A. Berger, S. Ranta, R. French, M. Richter, and T. Tanahashi Infrared and Electroluminescence Imaging for PV Field Applications: An Overview of the Latest Report by IEA PVPS Task 13 Inproceedings Forthcoming WIP (Hrsg.): Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition, Brussels, Belgium, Forthcoming. @inproceedings{Tsanakas2018,
title = {Infrared and Electroluminescence Imaging for PV Field Applications: An Overview of the Latest Report by IEA PVPS Task 13}, author = {J A Tsanakas and U Jahn and M Herz and M Köntges and D Parlevliet and M Paggi and J S Stein and K A Berger and S Ranta and R French and M Richter and T Tanahashi}, editor = {WIP}, year = {2018}, date = {2018-09-24}, booktitle = {Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition}, address = {Brussels, Belgium}, keywords = {EL}, pubstate = {forthcoming}, tppubtype = {inproceedings} } |
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T. Gewohn, S. Blankemeyer, M. R. Vogt, H. Schulte-Huxel, M. Köntges, B. Lim, C. Schinke, and R. Brendel Laminated Textiles Enabling Custom Appearance of Building Integrated Photovoltaic Modules Inproceedings Forthcoming WIP (Hrsg.): Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition, Brussels, Belgium, Forthcoming. @inproceedings{Gewohn2018,
title = {Laminated Textiles Enabling Custom Appearance of Building Integrated Photovoltaic Modules}, author = {T Gewohn and S Blankemeyer and M R Vogt and H Schulte-Huxel and M Köntges and B Lim and C Schinke and R. Brendel}, editor = {WIP}, year = {2018}, date = {2018-09-24}, booktitle = {Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition}, address = {Brussels, Belgium}, keywords = {BIPV}, pubstate = {forthcoming}, tppubtype = {inproceedings} } |
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J. Ulbikas, J. Denafas, M. Köntges, M. Topic, F. Frontini, P. Macé, P. J. Bolt, A. G. Ulyashin, T. Haarberg, W. Palitzsch, B. Terheiden, and I. Weiss Introducing the Super PV Project - Cost Reduction and Enhanced Performance of PV Systems Inproceedings Forthcoming WIP (Hrsg.): Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition, Brussels, Belgium, Forthcoming. BibTeX | Schlagwörter: Horizon2020 @inproceedings{Ulbikas2018,
title = {Introducing the Super PV Project - Cost Reduction and Enhanced Performance of PV Systems}, author = {J Ulbikas and J Denafas and M Köntges and M Topic and F Frontini and P Macé and P J Bolt and A G Ulyashin and T Haarberg and W Palitzsch and B Terheiden and I Weiss}, editor = {WIP}, year = {2018}, date = {2018-09-24}, booktitle = {Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition}, address = {Brussels, Belgium}, keywords = {Horizon2020}, pubstate = {forthcoming}, tppubtype = {inproceedings} } |
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F. Giovannetti Performance Assessment of a Photovoltaic-Thermal Roof with Modular Heat Exchanger Inproceedings Forthcoming EuroSun 2018: International Conference on Solar Energy and Buildings, Rapperswil, Switzerland, Forthcoming. @inproceedings{Giovannetti2018,
title = {Performance Assessment of a Photovoltaic-Thermal Roof with Modular Heat Exchanger }, author = {F Giovannetti}, year = {2018}, date = {2018-09-13}, booktitle = {EuroSun 2018: International Conference on Solar Energy and Buildings}, address = {Rapperswil, Switzerland}, keywords = {PVT}, pubstate = {forthcoming}, tppubtype = {inproceedings} } |
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M. Schnabel, M. Rienäcker, E. L. Warren, J. F. Geisz, R. Peibst, P. Stradins, and A. C. Tamboli Equivalent Performance in Three-Terminal and Four-Terminal Tandem Solar Cells Artikel Forthcoming IEEE Journal of Photovoltaics 1-6 Forthcoming, ISSN: 2156-3381. Links | BibTeX | Schlagwörter: Absorption, Computer architecture, Current measurement, Density measurement, III-V semiconductor materials, Microprocessors, Photovoltaic cells, Power system measurements, silicon @article{Schnabel2018b,
title = {Equivalent Performance in Three-Terminal and Four-Terminal Tandem Solar Cells}, author = {M Schnabel and M Rienäcker and E L Warren and J F Geisz and R Peibst and P Stradins and A C Tamboli}, doi = {10.1109/JPHOTOV.2018.2865175}, issn = {2156-3381}, year = {2018}, date = {2018-09-05}, journal = {IEEE Journal of Photovoltaics}, pages = {1-6}, keywords = {Absorption, Computer architecture, Current measurement, Density measurement, III-V semiconductor materials, Microprocessors, Photovoltaic cells, Power system measurements, silicon}, pubstate = {forthcoming}, tppubtype = {article} } |
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B. Schiebler, S. Jack, H. Dieckmann, and F. Giovannetti Solar Energy 171 , 271-278 (2018), ISSN: 0038-092X. Abstract | Links | BibTeX | Schlagwörter: cost reduction, evacuated tube collector, Flat plate collector, heat pipe, stagnation temperature, Superheated vapour @article{Schiebler2018d,
title = {Experimental and theoretical investigations on temperature limitation in solar thermal collectors with heat pipes: Effect of superheating on the maximum temperature}, author = {B Schiebler and S Jack and H Dieckmann and F Giovannetti}, doi = {10.1016/j.solener.2018.06.036}, issn = {0038-092X}, year = {2018}, date = {2018-09-01}, journal = {Solar Energy}, volume = {171}, pages = {271-278}, abstract = {Heat pipes in solar thermal collectors enable to reduce the temperature loads in the solar circuit during stagnation periods by exploiting their dry-out limit. With this approach vapour formation in the solar circuit can be completely avoided, which is essential to reduce costs of solar thermal systems by simplified and more reliable solar circuits. The design of “deactivating” collector heat pipes with a desired maximum temperature requires a comprehensive understanding of the heat transfer processes in the heat pipe, in particular when dry-out takes place. We developed a model, which allows calculating the maximum fluid temperature in the collector for various working fluids. Compared to existing approaches, the effect of superheated vapour in the heat pipe during stagnation is additionally considered. The paper describes the theoretical model in detail and its extensive experimental validation. The results show that the model is able to predict the maximum fluid temperature with an accuracy better than 5 K. Based on parametric studies with different working fluids, we analyse and discuss the temperature limitation and its effect on the collector performance.}, keywords = {cost reduction, evacuated tube collector, Flat plate collector, heat pipe, stagnation temperature, Superheated vapour}, pubstate = {published}, tppubtype = {article} } Heat pipes in solar thermal collectors enable to reduce the temperature loads in the solar circuit during stagnation periods by exploiting their dry-out limit. With this approach vapour formation in the solar circuit can be completely avoided, which is essential to reduce costs of solar thermal systems by simplified and more reliable solar circuits. The design of “deactivating” collector heat pipes with a desired maximum temperature requires a comprehensive understanding of the heat transfer processes in the heat pipe, in particular when dry-out takes place. We developed a model, which allows calculating the maximum fluid temperature in the collector for various working fluids. Compared to existing approaches, the effect of superheated vapour in the heat pipe during stagnation is additionally considered. The paper describes the theoretical model in detail and its extensive experimental validation. The results show that the model is able to predict the maximum fluid temperature with an accuracy better than 5 K. Based on parametric studies with different working fluids, we analyse and discuss the temperature limitation and its effect on the collector performance.
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V. Titova, D. Startsev, and J. Schmidt AIP (Hrsg.): AIP Conference Proceedings 1999 (1), 040022 Lausanne, Switzerland, (2018), (SILICONPV 2018, THE 8TH INTERNATIONAL CONFERENCE ON CRYSTALLINE SILICON PHOTOVOLTAICS). Abstract | Links | BibTeX | Schlagwörter: @inproceedings{Titova2018,
title = {Electron-selective atomic-layer-deposited TiOx layers: Impact of post-deposition annealing and implementation into n-type silicon solar cells}, author = {V Titova and D Startsev and J Schmidt}, editor = {AIP}, doi = {10.1063/1.5049285}, year = {2018}, date = {2018-08-10}, booktitle = {AIP Conference Proceedings 1999 (1)}, journal = {AIP Conference Proceedings}, volume = {1999}, number = {1}, pages = {040022}, address = {Lausanne, Switzerland}, abstract = {Atomic-layer-deposited titanium oxide (TiOx) is examined for the application as electron-selective full-area contact to n−type silicon solar cells. Although the surface passivation quality of TiOx-passivated n−type silicon wafers is quite poor directly after deposition of the TiOx, we demonstrate that annealing in ambient environment at only 250°C reduces the surface recombination velocity to values below 10 cm/s over the entire cell-relevant injection range. By combining lifetime measurements with X-ray diffraction (XRD) characterization we demonstrate that the degradation of the passivation by TiOx during annealing at increased temperature is due to the crystallization of the amorphous TiOx into the crystalline anatase phase. We implement our optimized ALD-TiOx layers as electron-selective full-area rear contacts into n-type silicon solar cells and reach efficiencies up to 20.3% after low-temperature annealing in our first batch. The surface recombination velocity Srear at the cell rear, as extracted from the measured spectral internal quantum efficiency, is (52±20) cm/s. Interestingly, the fabricated solar cells show a much better thermal stability compared to the lifetime test structures, which seems to be a fundamental difference. The main difference of the finished solar cells to our lifetime test structures is that the TiOx layer is fully covered with aluminum in the solar cells. This suggests an interaction of Al with the ultrathin TiOx layer, resulting in an improved thermal stability.}, note = {SILICONPV 2018, THE 8TH INTERNATIONAL CONFERENCE ON CRYSTALLINE SILICON PHOTOVOLTAICS}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } Atomic-layer-deposited titanium oxide (TiOx) is examined for the application as electron-selective full-area contact to n−type silicon solar cells. Although the surface passivation quality of TiOx-passivated n−type silicon wafers is quite poor directly after deposition of the TiOx, we demonstrate that annealing in ambient environment at only 250°C reduces the surface recombination velocity to values below 10 cm/s over the entire cell-relevant injection range. By combining lifetime measurements with X-ray diffraction (XRD) characterization we demonstrate that the degradation of the passivation by TiOx during annealing at increased temperature is due to the crystallization of the amorphous TiOx into the crystalline anatase phase. We implement our optimized ALD-TiOx layers as electron-selective full-area rear contacts into n-type silicon solar cells and reach efficiencies up to 20.3% after low-temperature annealing in our first batch. The surface recombination velocity Srear at the cell rear, as extracted from the measured spectral internal quantum efficiency, is (52±20) cm/s. Interestingly, the fabricated solar cells show a much better thermal stability compared to the lifetime test structures, which seems to be a fundamental difference. The main difference of the finished solar cells to our lifetime test structures is that the TiOx layer is fully covered with aluminum in the solar cells. This suggests an interaction of Al with the ultrathin TiOx layer, resulting in an improved thermal stability.
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C. Gemmel, J. Hensen, N. Folchert, F. Haase, R. Peibst, S. Kajari-Schröder, and R. Brendel 9 ms carrier lifetime in kerfless epitaxial wafers by n-type POLO gettering Inproceedings AIP (Hrsg.): AIP Conference Proceedings 1999 (1), 130005 Lausanne, Switzerland, (2018), (SILICONPV 2018, THE 8TH INTERNATIONAL CONFERENCE ON CRYSTALLINE SILICON PHOTOVOLTAICS). Abstract | Links | BibTeX | Schlagwörter: @inproceedings{Gemmel2018b,
title = {9 ms carrier lifetime in kerfless epitaxial wafers by n-type POLO gettering}, author = {C Gemmel and J Hensen and N Folchert and F Haase and R Peibst and S Kajari-Schröder and R Brendel}, editor = {AIP}, doi = {10.1063/1.5049324}, year = {2018}, date = {2018-08-10}, booktitle = {AIP Conference Proceedings 1999 (1)}, journal = {AIP Conference Proceedings}, volume = {1999}, number = {1}, pages = {130005}, address = {Lausanne, Switzerland}, abstract = {The bulk lifetime of epitaxially grown silicon wafers increases significantly after phosphorous diffusion gettering. A strong diffusion is advantageous for gettering but is not ideal for highest solar cell efficiencies. We find that gettering with an n-type polycrystalline silicon on oxide (POLO) junction increases the bulk lifetime of epitaxial wafers from originally 2.3 to 4.3 ms to finally up to 8 ms at an injection level Δp = 1015 cm−3. This lifetime increase as large as for phosphorous-diffusion gettering. However, POLO junctions have a superior surface passivation when compared to diffused junctions. This offers a novel gettering process that not only increase the charge carrier lifetime of epitaxial wafers but can also be effectively integrated into a solar cell processes employing POLO junctions.}, note = {SILICONPV 2018, THE 8TH INTERNATIONAL CONFERENCE ON CRYSTALLINE SILICON PHOTOVOLTAICS}, keywords = {}, pubstate = {published}, tppubtype = {inproceedings} } The bulk lifetime of epitaxially grown silicon wafers increases significantly after phosphorous diffusion gettering. A strong diffusion is advantageous for gettering but is not ideal for highest solar cell efficiencies. We find that gettering with an n-type polycrystalline silicon on oxide (POLO) junction increases the bulk lifetime of epitaxial wafers from originally 2.3 to 4.3 ms to finally up to 8 ms at an injection level Δp = 1015 cm−3. This lifetime increase as large as for phosphorous-diffusion gettering. However, POLO junctions have a superior surface passivation when compared to diffused junctions. This offers a novel gettering process that not only increase the charge carrier lifetime of epitaxial wafers but can also be effectively integrated into a solar cell processes employing POLO junctions.
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