M Siebert; A Morlier; M Köntges
Temperature effect on UV fluorescence Vortrag
Emmerthal, Germany, 12.10.2018, (Workshop on UV Fluorescence Measurement for Damage Assessment of PV Modules).
@misc{Siebert2018,
title = {Temperature effect on UV fluorescence},
author = {M Siebert and A Morlier and M Köntges},
url = {https://isfh.de/publikationen/isfh-workshops-proceedings/uv-fluorescence-workshop/},
year = {2018},
date = {2018-10-12},
address = {Emmerthal, Germany},
note = {Workshop on UV Fluorescence Measurement for Damage Assessment of PV Modules},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
M Koehl; S Saile; K-A Weiß; S Fischer; M Meir; G Wallner; Y Louvet; F Giovannetti; F Veynandt; D Mugnier; D Philippen; A Thür
Price reduction of solar thermal system – Results of IEA SHC Task 54 Proceedings Article
In: AEE, (Hrsg.): Proceedings 1st International Sustainable Energy Conference (ISEC), S. 429-436, Graz, Austria, 2018.
@inproceedings{Koehl2018,
title = {Price reduction of solar thermal system – Results of IEA SHC Task 54},
author = {M Koehl and S Saile and K-A Weiß and S Fischer and M Meir and G Wallner and Y Louvet and F Giovannetti and F Veynandt and D Mugnier and D Philippen and A Thür},
editor = {AEE},
year = {2018},
date = {2018-10-05},
booktitle = {Proceedings 1st International Sustainable Energy Conference (ISEC)},
pages = {429-436},
address = {Graz, Austria},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
N Folchert; M Rienäcker; A A Yeo; B Min; R Peibst; R Brendel
Temperature-dependent contact resistance of carrier selective Poly-Si on oxide junctions Artikel
In: Solar Energy Materials and Solar Cells, Bd. 185, S. 425-430, 2018, ISSN: 0927-0248.
@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 = {},
pubstate = {published},
tppubtype = {article}
}
L Helmich; D C Walter; D Bredemeier; R Falster; V V Voronkov; J Schmidt
In-situ characterization of electron-assisted regeneration of Cz-Si solar cells Artikel
In: Solar Energy Materials and Solar Cells, Bd. 185, S. 283-286, 2018, ISSN: 0927-0248.
@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 = {},
pubstate = {published},
tppubtype = {article}
}
C Klamt; M Rienäcker; F Haase; N Folchert; R Brendel; R Peibst; V Krausse; J Krügener
Intrinsic Poly-Crystalline Silicon Region in between the p+ and n+ POLO Contacts of an 26.1%-Efficient IBC Solar Cell Vortrag
Brussels, Belgium, 26.09.2018, (35th European Photovoltaic Solar Energy Conference and Exhibition).
@misc{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 = {2018-09-26},
booktitle = {Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition},
address = {Brussels, Belgium},
abstract = {We investigate the impact of an intrinsic poly-crystalline silicon (i poly-Si) region between p+-type poly-Si and n+- type poly-Si regions in interdigitated back contacted solar cells with poly Si on oxide (POLO) passivating contacts. The purpose of these i poly-Si regions is to avoid a lateral pn poly-Si junction between the BSF and emitter fingers, which would mediate a high recombination current. Regarding this aspect, large i poly-Si region widths are preferable. On the other hand, we observe on full-area lifetime test structures a poor passivation of the crystalline Si absorber by the intrinsic poly-Si, corresponding to saturation current density of 309 fA/cm2. Regarding this aspect, small i poly-Si region widths are preferable. In order to find an optimum between these counteracting requirements, we perform a systematic investigation on poly-Si pin diode test structures with varying i poly-Si region widths from dgap = 0 to 380 μm. We indeed observe a strong decrease of the pin diode recombination current density J with increasing i region width, especially in the range between 30 and 40 μm where J changes over four orders of magnitude. Already for an i region width of 20 μm, the recombination current density of the pin diode is one order of magnitude smaller than the total recombination current density of our cells and is therefore not limiting the device performance any more. We consequently apply an i poly-Si width of 30 μm to a POLO interdigitated back contacted (IBC) solar cell and achieve an independently confirmed energy conversion efficiency of 26.1% [2]. Puzzlingly, the area-weighted J0 value of the 30 μm small i region (41.2 fA/cm2) is not consistent with the total J01 value measured on our cell (21 fA/cm2). Obviously, the passivation of the crystalline absorber by the intrinsic poly-Si areas embedded in the pin diodes is much better than on full-area lifetime test structures. Our hypothesis explaining this observation is that during the high-temperature POLOjunction formation step a lateral diffusion of the p+-type and n+-type dopants into the initially intrinsic region takes place. We confirm experimentally that this significantly reduces the actual width of the intrinsic poly-Si region.},
note = {35th European Photovoltaic Solar Energy Conference and Exhibition},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
V Titova; J Schmidt
Implementation of full-area-deposited electron-selective TiOx layers into silicon solar cells Vortrag
Brussels, Belgium, 26.09.2018, (35th European Photovoltaic Solar Energy Conference and Exhibition).
@misc{Titova2018b,
title = {Implementation of full-area-deposited electron-selective TiOx layers into silicon solar cells},
author = {V Titova and J Schmidt},
year = {2018},
date = {2018-09-26},
address = {Brussels, Belgium},
abstract = {We present results of crystalline silicon solar cells with an electron-selective contact provided by ultrathin titanium oxide (TiOx) films deposited by atomic layer deposition (ALD). We combine a SiOy/TiOx/Al electron-selective rear contact and a boron-diffused emitter passivated by an Al2O3/SiNx stack at the cell front on an n-type Cz-Si wafer. An open-circuit voltage of 661 mV is achieved for a solar cell with a 3 nm thick TiOx layer. For thinner TiOx layers the passivation quality is reduced, however, the solar cells still show open-circuit voltage exceeding 650 mV. An effective surface passivation of the cell rear is an important prerequisite for obtaining high efficiencies. In a first cell run, we demonstrate the feasibility of this concept, however, the actual cell efficiency of 20.3% is not limited by the TiOx layer selectivity, but by a reduced short-circuit current density Jsc and an increased series resistance Rs. By varying the metallization grid design on the front side, a series resistance of only 0.3 Ωcm2 was achieved, which directly correlates with a significant improvement in fill factor to 81.2%, clearly demonstrating that the ultrathin TiOx layer allows a good transport of majority carriers (electrons) and an effective blocking of minority carriers.},
note = {35th European Photovoltaic Solar Energy Conference and Exhibition},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
A Merkle; B Min; R Brendel; R Peibst; S Seren; H Knauss; R Nissler; J Steffens; B Terheiden
Atmospheric Pressure Chemical Vapor Deposition of in-Situ Doped Amorphous Silicon Layers for Passivating Contacts Proceedings Article
In: WIP, (Hrsg.): Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition, S. 785-791, Brussels, Belgium, 2018.
@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},
doi = {10.4229/35thEUPVSEC20182018-2DV.3.49},
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},
pages = {785-791},
address = {Brussels, Belgium},
abstract = {Atmospheric Pressure Chemical Vapor Deposition (APCVD) is so far used for the deposition of doped and undoped oxides. We upgrade an industrial in-line APCVD tool from Schmid Thermal Systems and develop potential cost-effective APCVD processes for deposition of intrinsic and in-situ-doped amorphous silicon (a-Si) layers. In this work we report for the first time on in-situ phosphorus-doped n+-type and boron-doped p+-type APCVD silicon layers. For n+-type and p+-type polysilicon on oxide (POLO) junctions based on these layers we demonstrate saturation current densities J0 < 6 fA/cm², implied open circuit voltages iVoc of 721 mV and 730 mV respectively, and simultaneously low junction resistivity c of 18 mΩcm². These properties enable the implementation of these layers as carrier-selective passivating contacts in solar cells. First industrial proof-of-concept solar cells using boron-doped p+- type APCVD layers are presented. We show that the p+-type APCVD POLO junction formation is possible by firing only and present an industrial feasible cell process for its drop-in implementation in current passivated emitter and rear cell (PERC) process flow.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
C N Kruse; K Bothe; B Lim; T Dullweber; R Brendel
Synergistic Efficiency Gain Analyses for the Photovoltaic Community: An Easy to Use SEGA Simulation Tool for Silicon Solar Cells Proceedings Article
In: WIP, (Hrsg.): Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition, S. 249-253, Brussels, Belgium, 2018.
@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},
doi = {10.4229/35thEUPVSEC20182018-2AO.4.3},
year = {2018},
date = {2018-09-24},
booktitle = {Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition},
pages = {249-253},
address = {Brussels, Belgium},
abstract = {A synergistic efficiency gain analysis (SEGA) determines the efficiency gain to be expected when idealizing a certain cell property. Moreover, it provides valuable information about synergistic effects due to the coupling of loss mechanisms, e.g. various recombination losses. Here we introduce an easy to use simulation tool to the PV community for performing a SEGA for PERC, PERC+, PERT, and IBC silicon solar cells. The simulation tool comes with a graphical user interface. This SEGA-GUI creates the required set of input files after entering all experimental parameters, e. g. the sheet resistance and recombination current of an emitter. The SEGA-GUI then performs the simulations by running Quokka 2 and analyzes the results. Programming knowledge is not required. The SEGA-GUI is designed to help the user in finding options for efficiency improvements. In this work we analyze our 22.1%-efficient PERC+ solar cell. The SEGA-GUI can be downloaded for free from the ISFH website.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
R Brendel; C Kruse; A Merkle; R Peibst
Screening Selective Contact Material Combinations for Novel Crystalline Si Cell Structures Proceedings Article
In: WIP, (Hrsg.): Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition, S. 39-46, Brussels, Belgium, 2018.
@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},
doi = {10.4229/35thEUPVSEC20182018-1AO.2.6},
year = {2018},
date = {2018-09-24},
booktitle = {Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition},
pages = {39-46},
address = {Brussels, Belgium},
abstract = {High efficiency crystalline Si solar cells require contacts with high carrier selectivity. This is ensured for contacts having low recombination currents as well as low contact resistances. A large variety of material systems for electron- and hole-selective contacts were measured in the literature. We screen a subset of electron- and hole-selective contacts to find promising combinations in terms of efficiency potential on the one hand and in terms of practical processes on the other hand. We use modelling of ideal Si cells with non-ideal experimental contact properties to determine the maximum efficiency and the optimized areal contact fractions for many contact combinations. Cells using a-Si and/or poly-Si contacts have the highest contact-limited efficiencies. Such cells are, however, quite different from today’s PERC technology. We therefore also look for contact combinations that have one contact type equal to the current PERC technology and identify cell structures that combine a poly-Si(n) contact with a screen-printed Al-doped contacts (PAL cells) as an attractive upgrade for the PERC technology. We also report on experimental work on building blocks for various types of PAL cells.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
M R Vogt; T Gewohn; K Bothe; R Brendel
Impact of Using Spectrally Resolved Ground Albedo Data for Performance Simulations of Bifacial Modules Proceedings Article
In: WIP, (Hrsg.): Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition, S. 1011-1016, Brussels, Belgium, 2018.
@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},
doi = {10.4229/35thEUPVSEC20182018-5BO.9.5},
year = {2018},
date = {2018-09-24},
booktitle = {Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition},
pages = {1011-1016},
address = {Brussels, Belgium},
abstract = {We simulate the average annual current gain fbif,spe of bifacial PV modules versus monofacial PV modules for various ground albedos and mounting conditions. Our in-house developed ray tracing framework DAIDALOS is used to compute various spectrally resolved rear and front side photon flux. We demonstrate that the annual current gain fbif,spe and as a consequence the energy yield of a bifacial module may vary by up to 35%abs when considering different ground albedos and by up to 10%abs when considering different mounting heights. Considering the difference between using spectrally resolved albedo data and averaged albedo data with respect to wavelength, we find relative deviations in the bifacial gain of up to 19.5%rel. We find that the deviation is reduced to 2.6%rel by weighting the albedo with both the external quantum efficiency of the photovoltaic module and the spectrum.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
D Bredemeier; D C Walter; J Schmidt
Production Compatible Remedy Against LeTID in High-Performance Multicrystalline Silicon Solar Cells Proceedings Article
In: WIP, (Hrsg.): Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition, S. 406-409, Brussels, Belgium, 2018.
@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},
doi = {10.4229/35thEUPVSEC20182018-2CO.9.4},
year = {2018},
date = {2018-09-24},
booktitle = {Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition},
pages = {406-409},
address = {Brussels, Belgium},
abstract = {We examine the ‘LeTID’ (Light and elevated Temperature Induced Degradation) effect and the subsequent regeneration in high-performance multicrystalline silicon (mc-Si). We treat lifetime samples and PERC solar cells with a production-compatible inline regeneration furnace (c.REG) from centrotherm international AG and demonstrate that this industrial-type regeneration treatment is capable of effectively suppressing LeTID. On lifetime samples, we observe an increase in the lifetime by one order of magnitude compared to the untreated and fully degraded samples. On finished industrial-type PERC solar cells, the c.REG treatment results in a gain of 6 to 14 mV in the open-circuit voltage at the point of maximum degradation compared to untreated reference solar cells. This compares to a relative gain in conversion efficiency of up to 6.8%.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
D C Walter; L Helmich; D Bredemeier; J Schmidt; R Falster; V V Voronkov
Lifetime Evolution during Regeneration in Boron-Doped Czochralski-Silicon Proceedings Article
In: WIP, (Hrsg.): Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition, S. 522-526, Brussels, Belgium, 2018.
@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},
doi = {10.4229/35thEUPVSEC20182018-2AV.1.29},
year = {2018},
date = {2018-09-24},
booktitle = {Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition},
pages = {522-526},
address = {Brussels, Belgium},
abstract = {We measure the evolution of the carrier lifetime in boron-doped Czochralski-grown silicon wafers for the first time in-situ during permanent deactivation of the boron-oxygen defect under the applied conditions, i.e. illumination with a halogen lamp at elevated temperatures. Applying illumination intensities ≥1 sun on standard 1.5 Ωcm p-type Cz-Si, the lifetime (measured at the regeneration temperature) changes only negligibly during this regeneration process. As expected, in this case, the time dependence of the defect concentration (measured at room temperature) follows a single-exponential decay function during regeneration. For light intensities << 1 sun on the same material, the lifetime shows a significant change during the regeneration conditions and the evolution of the defect concentration does no longer follow a single-exponential decay curve. In addition, on 0.5 Ωcm p-type Cz-Si we observe a non-exponential decay of the defect concentration for a regeneration treatment performed at 1 sun illumination intensity and a single-exponential decay for a higher illumination intensity of 2.9 suns. These observations are well compatible with a deactivation rate increasing proportionally with the excess carrier concentration.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
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; 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 Proceedings Article
In: WIP, (Hrsg.): Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition, S. 229-232, Brussels, Belgium, 2018.
@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},
doi = {10.4229/35thEUPVSEC20182018-2BP.1.4},
year = {2018},
date = {2018-09-24},
booktitle = {Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition},
pages = {229-232},
address = {Brussels, Belgium},
abstract = {The DISC project addresses the development of key technologies for the next generation of high-performance photovoltaic solar cells and modules. Our approach is to fully exploit the potential of silicon to its maximum by the use of passivating contacts or carrier selective contacts and junctions. Such contacts allow for simple, non-patterned double-side contacted device architecture and an enhancement of the energy yield, which will be key elements for achieving very low levelized costs of electricity. In this paper, selected highlights are presented concerning the first 18 months in the development of cell and module components such as In-free transparent conductive oxide layers with low sputtering damage. The synergies and results created within DISC will be also interesting for a drop-in combination with other solar cell and module technologies.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
B Lim; A Merkle; R Peibst; T Dullweber; Y Wang; R Zhou
LID - Free PERC+ Solar Cells with Stable Efficiencies Up to 22.1% Proceedings Article
In: WIP, (Hrsg.): Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition, S. 359-365, Brussels, Belgium, 2018.
@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},
doi = {10.4229/35thEUPVSEC20182018-2BO.3.2},
year = {2018},
date = {2018-09-24},
booktitle = {Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition},
pages = {359-365},
publisher = {Brussels, Belgium},
abstract = {e evaluate the potential of advanced B-doped Cz-Si with extremely low oxygen concentration ([Oi]) of 2.6 ppma as well as Ga-doped Cz-Si to avoid light-induced degradation (LID) in state-of-the-art bifacial PERC+ solar cells. We compare these materials to current industry standard B-doped Cz-Si with [Oi] between 12 and 16 ppma.. We measure the solar cell efficiency and the lifetime of samples processed in parallel to the solar cells in three important states: as-processed, after illumination at room temperature (degraded), and after illumination at elevated temperature (regenerated). In the as-processed state, the low [Oi] as well as the Ga-doped solar cells yield 0.2%abs to 0.3%abs higher efficiencies than the industrial B-doped Cz-Si. In addition, their efficiency is stable under illumination at room temperature. Furthermore, the measured bulk lifetimes are used as input parameters in a device simulation. Subsequently, we compare the simulated solar cell efficiencies to the measured efficiencies. For the industry standard B-doped Cz-Si, the simulation predicts 0.7%abs loss due to LID, which fits to the experimental result. After regeneration, the device simulation predicts an increase by 0.4%abs compared to the as-processed state, whereas the measured PERC+ efficiency improves only to the as-processed level. We discuss possible reasons for this discrepancy.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
J A Tsanakas; U Jahn; M Herz; M Köntges; D Parlevliet; M Paggi; J S Stein; K A Berger; B Kubicek; S Ranta; R French; M Richter; T Tanahashi
Infrared and Electroluminescence Imaging for PV Field Applications: An Overview of the Latest Report by IEA PVPS Task 13 Proceedings Article
In: WIP, (Hrsg.): Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition, S. 1440-1447, Brussels, Belgium, 2018.
@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 B Kubicek and S Ranta and R French and M Richter and T Tanahashi},
editor = {WIP},
doi = {10.4229/35thEUPVSEC20182018-6DP.2.4},
year = {2018},
date = {2018-09-24},
booktitle = {Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition},
pages = {1440-1447},
address = {Brussels, Belgium},
abstract = {This paper presents an overview of the latest research and technical reporting activity of TASK13 participants, within the Subtask 3.3 (“Characterization of PV Module Condition in the Field”); and particularly, key findings of the new “Review on Infrared (IR) and Electroluminescence (EL) Imaging for PV Field Applications” TASK13 Report. Goal of the latter is to provide guidelines and recommendations for using IR and EL imaging, in order to identify and assess specific failure modes of PV modules and systems in field applications. As such, the paper provides first a discussion on the relevant state-of-the-art and particularly the new IEC standards, Technical Specifications (TS) and guidelines. It also describes current practices for IR and EL imaging of PV modules and systems, looking at environmental and device requirements and the interpretation of sample patterns with abnormalities. In addition, examples of typical inspection results are given, showing characteristic IR/thermal and EL signatures of different failure modes occurring in fielded PV modules and arrays.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
T Gewohn; S Blankemeyer; M R Vogt; H Schulte-Huxel; M Köntges; B Lim; C Schinke; R. Brendel
Laminated Textiles Enabling Custom Appearance of Building Integrated Photovoltaic Modules Proceedings Article
In: WIP, (Hrsg.): Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition, S. 1842-1844, Brussels, Belgium, 2018.
@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},
doi = {10.4229/35thEUPVSEC20182018-6BV.1.58},
year = {2018},
date = {2018-09-24},
booktitle = {Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition},
pages = {1842-1844},
address = {Brussels, Belgium},
abstract = {We present a new technique to alter the appearance of photovoltaic (PV) modules for building integration by laminating textiles and other customary materials onto the front of PV modules. This approach is highly customizable, since we can use virtually any thin UV-stable textile, whether it is a plain colored or a patterned textile. The short-circuit current density loss caused by the textile laminate is 6% to 11% for a whitish appearance. Textiles can be laminated to any standard PV module. Using commercially available materials and machines, this method is likely to be cost-efficient and readily available.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
J Ulbikas; V Ulbikaite; J Denafas; R Witteck; M Köntges; M Topic; F Frontini; P Bonomo; P Macé; P J Bolt; A G Ulyashin; T Haarberg; W Palitzsch; B Terheiden; I Weiss
Introducing the Super PV Project - Cost Reduction and Enhanced Performance of PV Systems Proceedings Article
In: WIP, (Hrsg.): Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition, S. 2164-2168, Brussels, Belgium, 2018.
@inproceedings{Ulbikas2018,
title = {Introducing the Super PV Project - Cost Reduction and Enhanced Performance of PV Systems},
author = {J Ulbikas and V Ulbikaite and J Denafas and R Witteck and M Köntges and M Topic and F Frontini and P Bonomo 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},
doi = {10.4229/35thEUPVSEC20182018-7DV.2.8},
year = {2018},
date = {2018-09-24},
booktitle = {Proceedings of the 35th European Photovoltaic Solar Energy Conference and Exhibition},
pages = {2164-2168},
address = {Brussels, Belgium},
abstract = {Today photovoltaics (PV) has become one of the most cost-effective forms of electricity production globally and in some regions is already the most competitive unsubsidised form of electricity. Despite positive cost and growing developments, European PV manufacturers are facing a decline in production due to competition from third countries. This decrease in the competitiveness of European PV actors is due to several factors, including a greater fragmentation of the value chain compared to competing actors. Chinese manufacturers have in particular been able to achieve synergies, economies of scale and information sharing throughout the value chain. SUPER PV is a collaborative European-funded project initiated in 2018 by 26 partners in reaction to this trend. Together, they target a significant LCOE reduction (26%-37%) for European-made PV by adopting a hybrid approach combining technological innovations and data management methods.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
S Brötje; M Kirchner; T Schabbach; F Giovannetti
Performance Assessment of a Photovoltaic-Thermal Roof with Modular Heat Exchanger Proceedings Article
In: ISES, (Hrsg.): Proceedings 12th International Conference on Solar Energy for Buildings and Industry (EuroSun), S. 743-754, Rapperswil, Switzerland, 2018.
@inproceedings{Brötje2018c,
title = {Performance Assessment of a Photovoltaic-Thermal Roof with Modular Heat Exchanger},
author = {S Brötje and M Kirchner and T Schabbach and F Giovannetti},
editor = {ISES},
doi = {10.18086/eurosun2018.02.10},
year = {2018},
date = {2018-09-13},
booktitle = {Proceedings 12th International Conference on Solar Energy for Buildings and Industry (EuroSun)},
pages = {743-754},
address = {Rapperswil, Switzerland},
abstract = {Performance Assessment of a Photovoltaic-Thermal Roof with Modular Heat ExchangerSteffen Brötje1, Maik Kirchner1, Thomas Schabbach2and Federico Giovannetti11Institute for Solar Energy Research GmbH Hamelin (ISFH), Am Ohrberg 1, 31860 EmmerthalTel.: +495151/999-501; E-Mail: giovannetti@isfh.de2Hochschule Nordhausen, Institut für Regenerative Energietechnik, Weinberghof 4, 99734 NordhausenAbstractThispaper presents the thermal performance of a novel photovoltaic-thermal (PV/T) system conceived for roof integration. The methods of prototype design are described briefly. Main feature of the system is the modular assembly of the metallic heat exchanger, which also serves as self-supporting mounting device for the photovoltaic modules and assumes a static function. The design of the heat exchanger has been optimized by using numerical FEM simulations withregard toboth energetic and economic requirements. We investigate the performance of the system by means of long-term measurements on a large-sized PV/T roof prototype equipped with thin film CdTe photovoltaic modules under real weather conditions and at different operation conditions. The evaluation iscarried out according to the Standard ISO 9806, focusing on thequasi-dynamic test method. The experimental results (η0},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
S Müller; F Giovannetti; B Hafner; R Reineke-Koch
Experimental Investigations on the Stagnation Behavior of Thermochromic Flat Plate Collectors Proceedings Article
In: ISES, (Hrsg.): Proceedings 12th International Conference on Solar Energy for Buildings and Industry (EuroSun), S. 1032-1042, Rapperswil, Switzerland, 2018.
@inproceedings{Müller2018b,
title = {Experimental Investigations on the Stagnation Behavior of Thermochromic Flat Plate Collectors},
author = {S Müller and F Giovannetti and B Hafner and R Reineke-Koch},
editor = {ISES},
doi = {10.18086/eurosun2018.10.03},
year = {2018},
date = {2018-09-13},
booktitle = {Proceedings 12th International Conference on Solar Energy for Buildings and Industry (EuroSun)},
pages = {1032-1042},
address = {Rapperswil, Switzerland},
abstract = {A thermochromic absorber coating in a solar thermal flat plate collector switches its emissivity for long wave radiation depending on the absorber temperature. Thus, the stagnation temperature can be reduced by 30 K compared to a standard flat plate collector and an overheating of the heat transfer fluid can be prevented. On the basis of 58 selected stagnation events we analyze and compare the stagnation behavior of solar thermal systems with standard and thermochromic collectors. We have carried out well defined stagnation experiments to deter¬mine the steam expansion, steam volume and steam producing power for both solar thermal systems with unfa¬vorable system hydraulics. By the use of thermochromic collectors at a standard system overpressure (1.0 bar) the steam expansion can be halved, the overall steam volume can be lowered by 33 % and the stagnation time can be reduced by 20 %. The steam expansion and the vaporization of the heat transfer fluid can be prevented at system overpressures above 3.4 bar and 4.1 bar, respectively. The steam producing power can be limited to 40 W·m-2},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
B Schiebler; S Jack; H Dieckmann; F Giovannetti
In: Solar Energy, Bd. 171, S. 271-278, 2018, ISSN: 0038-092X.
@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 = {},
pubstate = {published},
tppubtype = {article}
}