1.
M Winter; D C Walter; B Min; R Peibst; R Brendel; J Schmidt
In: Scientific Reports, Bd. 12, S. 8089, 2022, ISSN: 2045-2322.
@article{Winter2022b,
title = {Light and elevated temperature induced degradation and recovery of gallium-doped Czochralski-silicon solar cells},
author = {M Winter and D C Walter and B Min and R Peibst and R Brendel and J Schmidt},
doi = {10.1038/s41598-022-11831-3},
issn = {2045-2322},
year = {2022},
date = {2022-05-16},
urldate = {2022-05-16},
journal = {Scientific Reports},
volume = {12},
pages = {8089},
abstract = {The fast-firing step commonly applied at the end of solar cell production lines is known to trigger light-induced degradation effects on solar cells made on different silicon materials. In this study, we examine degradation phenomena on high-efficiency solar cells with poly-Si passivating contacts made on Ga-doped Czochralski-grown silicon (Cz-Si) base material under one-sun illumination at elevated temperatures ranging from 80 to 160 textdegreeC. The extent of degradation is demonstrated to increase with the applied temperature up to 140 textdegreeC. Above 140 textdegreeC, the degradation extent decreases with increasing temperature. The degradation of the energy conversion efficiency can be ascribed foremost to a reduction of the short-circuit current and the fill factor and to a lesser extent to a reduction of the open-circuit voltage. The extent of degradation at 140 textdegreeC amounts to 0.4%abs of the initial conversion efficiency of 22.1% compared to 0.15%abs at 80 textdegreeC. The extent of the efficiency degradation in the examined solar cells is significantly lower (by a factor of textasciitildethinspace5) compared to solar cells made on B-doped Cz-Si wafers. Importantly, through prolonged illumination at elevated temperatures (e.g. 5 h, 1 sun, 140 textdegreeC), an improvement of the conversion efficiency by up to 0.2%abs compared to the initial value is achievable in combination with a permanent regeneration resulting in long-term stable conversion efficiencies above 22%.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The fast-firing step commonly applied at the end of solar cell production lines is known to trigger light-induced degradation effects on solar cells made on different silicon materials. In this study, we examine degradation phenomena on high-efficiency solar cells with poly-Si passivating contacts made on Ga-doped Czochralski-grown silicon (Cz-Si) base material under one-sun illumination at elevated temperatures ranging from 80 to 160 textdegreeC. The extent of degradation is demonstrated to increase with the applied temperature up to 140 textdegreeC. Above 140 textdegreeC, the degradation extent decreases with increasing temperature. The degradation of the energy conversion efficiency can be ascribed foremost to a reduction of the short-circuit current and the fill factor and to a lesser extent to a reduction of the open-circuit voltage. The extent of degradation at 140 textdegreeC amounts to 0.4%abs of the initial conversion efficiency of 22.1% compared to 0.15%abs at 80 textdegreeC. The extent of the efficiency degradation in the examined solar cells is significantly lower (by a factor of textasciitildethinspace5) compared to solar cells made on B-doped Cz-Si wafers. Importantly, through prolonged illumination at elevated temperatures (e.g. 5 h, 1 sun, 140 textdegreeC), an improvement of the conversion efficiency by up to 0.2%abs compared to the initial value is achievable in combination with a permanent regeneration resulting in long-term stable conversion efficiencies above 22%.
2.
M R Vogt; S Riechelmann; A M Gracia-Amillo; A Driesse; A Kokka; K Maham; P Kärhä; R Kenny; C Schinke; K Bothe; J C Blakesley; E Music; F Plag; G Friesen; G Corbellini; N Riedel-Lyngskær; R Valckenborg; M Schweiger; W Herrmann
In: IEEE Journal of Photovoltaics, Bd. 12, Ausg. 3, S. 844-852, 2022.
@article{Vogt2022,
title = {PV Module Energy Rating Standard IEC 61853-3 Intercomparison and Best Practice Guidelines for Implementation and Validation},
author = {M R Vogt and S Riechelmann and A M Gracia-Amillo and A Driesse and A Kokka and K Maham and P Kärhä and R Kenny and C Schinke and K Bothe and J C Blakesley and E Music and F Plag and G Friesen and G Corbellini and N Riedel-Lyngskær and R Valckenborg and M Schweiger and W Herrmann},
doi = {10.1109/JPHOTOV.2021.3135258},
year = {2022},
date = {2022-05-01},
urldate = {2022-03-10},
journal = {IEEE Journal of Photovoltaics},
volume = {12},
issue = {3},
pages = {844-852},
abstract = {The IEC 61853 standard series aims to provide a standardized measure for photovoltaic (PV) module energy rating, namely the Climate Specific Energy Rating (CSER). For this purpose, it defines procedures for the experimental determination of input data and algorithms for calculating the CSER. However, some steps leave room for interpretation regarding the specific implementation. To analyze the impact of these ambiguities, the comparability of results, and the clarity of the algorithm for calculating the CSER in Part 3 of the standard, an intercomparison is performed among research organizations with ten different implementations of the algorithm. We share the same input data, obtained by measurement of a commercial crystalline silicon PV module, among the participating organizations. Each participant then uses their individual implementations of the algorithm to calculate the resulting CSER values. The initial blind comparison reveals differences of 0.133 (14.7%) in CSER. After several comparison phases, a best practice approach is defined, which reduces the difference by a factor of 210 to below 0.001 (0.1%) in CSER for two independent PV modules. The best practice presented in this article establishes clear guidelines for the numerical treatment of the spectral correction and power matrix extrapolation, where the methods in the standard are not clearly defined. Additionally, we provide input data and results for the PV community to test their implementations of the standard's algorithm. To identify the source of the deviations, we introduce a climate data diagnostic set. Based on our experiences, we give recommendations for the future development of the standard.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The IEC 61853 standard series aims to provide a standardized measure for photovoltaic (PV) module energy rating, namely the Climate Specific Energy Rating (CSER). For this purpose, it defines procedures for the experimental determination of input data and algorithms for calculating the CSER. However, some steps leave room for interpretation regarding the specific implementation. To analyze the impact of these ambiguities, the comparability of results, and the clarity of the algorithm for calculating the CSER in Part 3 of the standard, an intercomparison is performed among research organizations with ten different implementations of the algorithm. We share the same input data, obtained by measurement of a commercial crystalline silicon PV module, among the participating organizations. Each participant then uses their individual implementations of the algorithm to calculate the resulting CSER values. The initial blind comparison reveals differences of 0.133 (14.7%) in CSER. After several comparison phases, a best practice approach is defined, which reduces the difference by a factor of 210 to below 0.001 (0.1%) in CSER for two independent PV modules. The best practice presented in this article establishes clear guidelines for the numerical treatment of the spectral correction and power matrix extrapolation, where the methods in the standard are not clearly defined. Additionally, we provide input data and results for the PV community to test their implementations of the standard's algorithm. To identify the source of the deviations, we introduce a climate data diagnostic set. Based on our experiences, we give recommendations for the future development of the standard.
3.
M Köntges; J Wagner; M Siebert; S Bordihn; C Schinke
In: IEEE Journal of Photovoltaics, Bd. 12, Ausg. 3, S. 805-814, 2022.
@article{Köntges2022,
title = {Applicability of Light Induced Luminescence for Characterization of Internal Series-Parallel Connected Photovoltaic Modules},
author = {M Köntges and J Wagner and M Siebert and S Bordihn and C Schinke},
doi = {10.1109/JPHOTOV.2022.3156727},
year = {2022},
date = {2022-05-01},
urldate = {2022-03-23},
journal = {IEEE Journal of Photovoltaics},
volume = {12},
issue = {3},
pages = {805-814},
abstract = {In this article, we present a new method to measure electroluminescence (EL) images of current half-cell PV modules without opening electrical contacts. The method uses the series parallel interconnection of the substrings in the module to power one module half (luminescence part) by illumination of the other module half (generator part). The defect interpretation of the resulting images changes slightly compared to usual EL images. Module defects in the generator part of the module influence the working point of the EL of the luminescence part. The new method has a practical limitation, as an electrical power of about 12.4 kW would be required for bringing the luminescent part into the operating point of the rated short-circuit current. Using infrared light emitting diodes and a working point of half of the nominal short-circuit power brings the needed power down to about 2.4 kW for a 144-cell module. For current Si-based PV modules, the method allows image acquisition times below 1 s per image with conventional silicon sensor-based cameras.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In this article, we present a new method to measure electroluminescence (EL) images of current half-cell PV modules without opening electrical contacts. The method uses the series parallel interconnection of the substrings in the module to power one module half (luminescence part) by illumination of the other module half (generator part). The defect interpretation of the resulting images changes slightly compared to usual EL images. Module defects in the generator part of the module influence the working point of the EL of the luminescence part. The new method has a practical limitation, as an electrical power of about 12.4 kW would be required for bringing the luminescent part into the operating point of the rated short-circuit current. Using infrared light emitting diodes and a working point of half of the nominal short-circuit power brings the needed power down to about 2.4 kW for a 144-cell module. For current Si-based PV modules, the method allows image acquisition times below 1 s per image with conventional silicon sensor-based cameras.
4.
S Bordihn; A Fladung; J Schlipf; M Köntges
In: IEEE Journal of Photovoltaics, Bd. 12, Ausg. 3, S. 827-832, 2022.
@article{Bordihn2022,
title = {Machine Learning Based Identification and Classification of Field-Operation Caused Solar Panel Failures Observed in Electroluminescence Images},
author = {S Bordihn and A Fladung and J Schlipf and M Köntges},
doi = {10.1109/JPHOTOV.2022.3150725},
year = {2022},
date = {2022-05-01},
urldate = {2022-02-28},
journal = {IEEE Journal of Photovoltaics},
volume = {12},
issue = {3},
pages = {827-832},
abstract = {Failure or degradation effects lead to power losses in solar panels during their field operation and are identified commonly by electroluminescence (EL) imaging. Some failures like potential-induced degradation (PID) and light and enhanced temperature induced degradation (LeTID) require an identification of the EL pattern over the entire solar panel. As the manual process of analyzing patterns is prone to error, we seek for an automatic detection of these failure types. We predict automatically the failure types PID and LeTID by adopting the principal component analysis (PCA) method in combination with a k-nearest neighbor (kNN) classifier. We increase the explained variance of the PCA by 4 %abs using a Gaussian blurring preprocessing step and gain insights into the basic mechanism of the machine learning algorithm by analyzing schematic EL images. The kNN classifier predicts the failure classes in the same way as the expert. Finally, we work with a larger test dataset of 40 similar images to mimic a field-typical user case and meet again the expert classification.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Failure or degradation effects lead to power losses in solar panels during their field operation and are identified commonly by electroluminescence (EL) imaging. Some failures like potential-induced degradation (PID) and light and enhanced temperature induced degradation (LeTID) require an identification of the EL pattern over the entire solar panel. As the manual process of analyzing patterns is prone to error, we seek for an automatic detection of these failure types. We predict automatically the failure types PID and LeTID by adopting the principal component analysis (PCA) method in combination with a k-nearest neighbor (kNN) classifier. We increase the explained variance of the PCA by 4 %abs using a Gaussian blurring preprocessing step and gain insights into the basic mechanism of the machine learning algorithm by analyzing schematic EL images. The kNN classifier predicts the failure classes in the same way as the expert. Finally, we work with a larger test dataset of 40 similar images to mimic a field-typical user case and meet again the expert classification.
5.
R Peibst; M Rienäcker; Y Larionova; N Folchert; F Haase; C Hollemann; S Wolter; J Krügener; P Bayerl; J Bayer; M Dzinnik; R J Haug; R Brendel
In: Solar Energy Materials and Solar Cells, Bd. 238, S. 111560, 2022, ISSN: 0927-0248.
@article{Peibst2022,
title = {Towards 28 %-efficient Si single-junction solar cells with better passivating POLO junctions and photonic crystals},
author = {R Peibst and M Rienäcker and Y Larionova and N Folchert and F Haase and C Hollemann and S Wolter and J Krügener and P Bayerl and J Bayer and M Dzinnik and R J Haug and R Brendel},
doi = {10.1016/j.solmat.2021.111560},
issn = {0927-0248},
year = {2022},
date = {2022-05-01},
urldate = {2022-01-20},
journal = {Solar Energy Materials and Solar Cells},
volume = {238},
pages = {111560},
abstract = {We conduct numerical device simulations to study to what extend poly-Si on oxide (POLO)2 IBC solar cells can be optimized. In particular, we evaluate the benefit of the concept of photonic crystals (PCs) for “standard” cell thicknesses compatible with industrial wafer handling. We find that for our current surface passivation quality, implementing PCs and decreasing the wafer thickness down to 15 μm would increase the efficiency by „only“ 1% absolute due to limiting surface recombination losses. We deduce a high c-Si/SiOx interface state density Dit of 2.9 × 1012 eV−1cm−2 by analyzing special two-terminal IV measurements on small pads that contact the intact interfacial oxide between pinholes with our MarcoPOLO model. Consequently, we improve the hydrogenation process of our POLO junctions by an Al2O3/SiNx/Al2O3 rear-side dielectric layer stack. For n-type POLO (p-type POLO) J0 is reduced from 4 (10) fA/cm2 down to 0.5 ± 0.3 (3.3 ± 0.7) fA/cm2. For this improved surface passivation, our numerical device simulations predict an efficiency potential of 29.1% (27.8%) for POLO2 IBC cells with (without) PCs for a standard thickness of 150 μm. This shows that the “practical limit” for Si solar cells with poly-Si on oxide-based passivating contact schemes is above 27%, and, in general, that the efficiency potential of Si single-junction cells is still far from being exhausted. The first implementation of the improved POLO junctions into cell precursors confirms the predicted improvement on the level of suns - implied open-circuit voltage curves.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We conduct numerical device simulations to study to what extend poly-Si on oxide (POLO)2 IBC solar cells can be optimized. In particular, we evaluate the benefit of the concept of photonic crystals (PCs) for “standard” cell thicknesses compatible with industrial wafer handling. We find that for our current surface passivation quality, implementing PCs and decreasing the wafer thickness down to 15 μm would increase the efficiency by „only“ 1% absolute due to limiting surface recombination losses. We deduce a high c-Si/SiOx interface state density Dit of 2.9 × 1012 eV−1cm−2 by analyzing special two-terminal IV measurements on small pads that contact the intact interfacial oxide between pinholes with our MarcoPOLO model. Consequently, we improve the hydrogenation process of our POLO junctions by an Al2O3/SiNx/Al2O3 rear-side dielectric layer stack. For n-type POLO (p-type POLO) J0 is reduced from 4 (10) fA/cm2 down to 0.5 ± 0.3 (3.3 ± 0.7) fA/cm2. For this improved surface passivation, our numerical device simulations predict an efficiency potential of 29.1% (27.8%) for POLO2 IBC cells with (without) PCs for a standard thickness of 150 μm. This shows that the “practical limit” for Si solar cells with poly-Si on oxide-based passivating contact schemes is above 27%, and, in general, that the efficiency potential of Si single-junction cells is still far from being exhausted. The first implementation of the improved POLO junctions into cell precursors confirms the predicted improvement on the level of suns - implied open-circuit voltage curves.
6.
G Wetzel; L Salomon; J Krügener; D Bredemeier; R Peibst
In: Progress in Photovoltaics: Research and Applications, Bd. 30, Ausg. 5, Nr. 543-551, 2022.
@article{Wetzel2021,
title = {High time resolution measurement of solar irradiance onto driving car body for vehicle integrated photovoltaics},
author = {G Wetzel and L Salomon and J Krügener and D Bredemeier and R Peibst},
doi = {10.1002/pip.3526},
year = {2022},
date = {2022-05-01},
urldate = {2021-12-20},
journal = {Progress in Photovoltaics: Research and Applications},
volume = {30},
number = {543-551},
issue = {5},
abstract = {Abstract Vehicle integrated photovoltaic (VIPV) systems have much different requirements on maximum power tracking compared to stationary setups. The occurrence of fast changes between full irradiance and shading are demanding. To evaluate the specific impact of these conditions on the specifications of VIPV systems, we conduct high resolution measurements of the incident irradiance onto a car body while driving. We investigate the influence of environmental conditions like weather, season and building density in an urban environment on measured irradiance on the roof and the sides of a vehicle. We find that weather conditions have the highest impact on the measured irradiance on the roof, while the relative irradiance on the side depends more heavily on the season. We also find that changes in irradiance occur predominantly at frequencies below 1 Hz, but changes with 100 Hz or more can occur in certain situations, with a tendency toward higher frequencies for sunny weather. This must be considered in maximum power point tracker design.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract Vehicle integrated photovoltaic (VIPV) systems have much different requirements on maximum power tracking compared to stationary setups. The occurrence of fast changes between full irradiance and shading are demanding. To evaluate the specific impact of these conditions on the specifications of VIPV systems, we conduct high resolution measurements of the incident irradiance onto a car body while driving. We investigate the influence of environmental conditions like weather, season and building density in an urban environment on measured irradiance on the roof and the sides of a vehicle. We find that weather conditions have the highest impact on the measured irradiance on the roof, while the relative irradiance on the side depends more heavily on the season. We also find that changes in irradiance occur predominantly at frequencies below 1 Hz, but changes with 100 Hz or more can occur in certain situations, with a tendency toward higher frequencies for sunny weather. This must be considered in maximum power point tracker design.
7.
D C Walter; V V Voronkov; R Falster; D Bredemeier; J Schmidt
In: Journal of Applied Physics, Bd. 131, Nr. 16, S. 165702, 2022, ISSN: 0021-8979.
@article{Walter2022,
title = {On the kinetics of the exchange of hydrogen between hydrogen--boron pairs and hydrogen dimers in crystalline silicon},
author = {D C Walter and V V Voronkov and R Falster and D Bredemeier and J Schmidt},
doi = {10.1063/5.0086307},
issn = {0021-8979},
year = {2022},
date = {2022-04-28},
urldate = {2022-04-28},
journal = {Journal of Applied Physics},
volume = {131},
number = {16},
pages = {165702},
publisher = {American Institute of Physics},
abstract = {Silicon samples after fast-firing with a hydrogen-rich silicon nitride layer on their surfaces can contain high concentrations of hydrogen (up to 6 × 1015 cm−3 in this study). Directly after fast-firing, this hydrogen is mostly present in a neutral dimeric state. Subsequent dark annealing applied in a temperature range between 140 and 175 °C leads to a conversion of dimers into HB pairs, which means that a significant number of boron acceptors are electrically inactive. The concentration of inactive boron, the hydrogen–boron (HB) pair concentration [HB], can thus be determined by measuring the change in specific resistivity before and after annealing. In our study, after the initial anneal for HB pair formation, the same samples are subsequently annealed at stepwise increasing higher temperatures, which leads to a partial backward conversion of HB pairs into neutral hydrogen dimers. This is indicated by a gradual reduction of the resistivity upon increasing the annealing temperature. By measuring the transient curves [HB](t) during each temperature step on samples with different boron content, we extract the parameters for the exchange between the HB pairs and the hydrogen dimers within the framework of our presented physical model. Apart from the backward formation of hydrogen dimers, from HB pairs upon increasing temperature, prolonged annealing at the same temperature leads to a transition of HB pairs into a more stable form of hydrogen dimers, compared to the initial form after fast-firing. This transition is also included in our proposed defect model.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Silicon samples after fast-firing with a hydrogen-rich silicon nitride layer on their surfaces can contain high concentrations of hydrogen (up to 6 × 1015 cm−3 in this study). Directly after fast-firing, this hydrogen is mostly present in a neutral dimeric state. Subsequent dark annealing applied in a temperature range between 140 and 175 °C leads to a conversion of dimers into HB pairs, which means that a significant number of boron acceptors are electrically inactive. The concentration of inactive boron, the hydrogen–boron (HB) pair concentration [HB], can thus be determined by measuring the change in specific resistivity before and after annealing. In our study, after the initial anneal for HB pair formation, the same samples are subsequently annealed at stepwise increasing higher temperatures, which leads to a partial backward conversion of HB pairs into neutral hydrogen dimers. This is indicated by a gradual reduction of the resistivity upon increasing the annealing temperature. By measuring the transient curves [HB](t) during each temperature step on samples with different boron content, we extract the parameters for the exchange between the HB pairs and the hydrogen dimers within the framework of our presented physical model. Apart from the backward formation of hydrogen dimers, from HB pairs upon increasing temperature, prolonged annealing at the same temperature leads to a transition of HB pairs into a more stable form of hydrogen dimers, compared to the initial form after fast-firing. This transition is also included in our proposed defect model.
8.
M Firat; L Wouters; P Lagrain; F Haase; J-I Polzin; A Chaudhary; G Nogay; T Desrues; J Krügener; R Peibst; L Tous; H Sivaramakrishnan Radhakrishnan; J Poortmans
Local Enhancement of Dopant Diffusion from Polycrystalline Silicon Passivating Contacts Artikel
In: ACS Applied Materials & Interfaces, 2022, ISSN: 1944-8244.
@article{Fırat2022,
title = {Local Enhancement of Dopant Diffusion from Polycrystalline Silicon Passivating Contacts},
author = {M Firat and L Wouters and P Lagrain and F Haase and J-I Polzin and A Chaudhary and G Nogay and T Desrues and J Krügener and R Peibst and L Tous and H Sivaramakrishnan Radhakrishnan and J Poortmans},
doi = {10.1021/acsami.2c01801},
issn = {1944-8244},
year = {2022},
date = {2022-04-05},
urldate = {2022-04-05},
journal = {ACS Applied Materials & Interfaces},
publisher = {American Chemical Society},
abstract = {Passivating contacts consisting of heavily doped polycrystalline silicon (poly-Si) and ultrathin interfacial silicon oxide (SiOx) films enable the fabrication of high-efficiency Si solar cells. The electrical properties and working mechanism of such poly-Si passivating contacts depend on the distribution of dopants at their interface with the underlying Si substrate of solar cells. Therefore, this distribution, particularly in the vicinity of pinholes in the SiOx film, is investigated in this work. Technology computer-aided design (TCAD) simulations were performed to study the diffusion of dopants, both phosphorus (P) and boron (B), from the poly-Si film into the Si substrate during the annealing process typically applied to poly-Si passivating contacts. The simulated 2D doping profiles indicate enhanced diffusion under pinholes, yielding deeper semicircular regions of increased doping compared to regions far removed from the pinholes. Such regions with locally enhanced doping were also experimentally demonstrated using high-resolution (5--10 nm/pixel) scanning spreading resistance microscopy (SSRM) for the first time. The SSRM measurements were performed on a variety of poly-Si passivating contacts, fabricated using different approaches by multiple research institutes, and the regions of doping enhancement were detected on samples where the presence of pinholes had been reported in the related literature. These findings can contribute to a better understanding, more accurate modeling, and optimization of poly-Si passivating contacts, which are increasingly being introduced in the mass production of Si solar cells.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Passivating contacts consisting of heavily doped polycrystalline silicon (poly-Si) and ultrathin interfacial silicon oxide (SiOx) films enable the fabrication of high-efficiency Si solar cells. The electrical properties and working mechanism of such poly-Si passivating contacts depend on the distribution of dopants at their interface with the underlying Si substrate of solar cells. Therefore, this distribution, particularly in the vicinity of pinholes in the SiOx film, is investigated in this work. Technology computer-aided design (TCAD) simulations were performed to study the diffusion of dopants, both phosphorus (P) and boron (B), from the poly-Si film into the Si substrate during the annealing process typically applied to poly-Si passivating contacts. The simulated 2D doping profiles indicate enhanced diffusion under pinholes, yielding deeper semicircular regions of increased doping compared to regions far removed from the pinholes. Such regions with locally enhanced doping were also experimentally demonstrated using high-resolution (5--10 nm/pixel) scanning spreading resistance microscopy (SSRM) for the first time. The SSRM measurements were performed on a variety of poly-Si passivating contacts, fabricated using different approaches by multiple research institutes, and the regions of doping enhancement were detected on samples where the presence of pinholes had been reported in the related literature. These findings can contribute to a better understanding, more accurate modeling, and optimization of poly-Si passivating contacts, which are increasingly being introduced in the mass production of Si solar cells.
9.
F Peterssen; M Schlemminger; C Lohr; R Niepelt; A Bensmann; R Hanke-Rauschenbach; R Brendel
Hydrogen supply scenarios for a climate neutral energy system in Germany Artikel
In: International Journal of Hydrogen Energy, Bd. 47, Ausg. 28, S. 13515-13523, 2022, ISSN: 0360-3199.
@article{Peterssen2022,
title = {Hydrogen supply scenarios for a climate neutral energy system in Germany},
author = {F Peterssen and M Schlemminger and C Lohr and R Niepelt and A Bensmann and R Hanke-Rauschenbach and R Brendel},
doi = {10.1016/j.ijhydene.2022.02.098},
issn = {0360-3199},
year = {2022},
date = {2022-04-01},
urldate = {2022-01-01},
journal = {International Journal of Hydrogen Energy},
volume = {47},
issue = {28},
pages = {13515-13523},
abstract = {A climate neutral energy system in Germany will most likely require green hydrogen. Two important factors, that determine whether the hydrogen will be imported or produced locally from renewable energy are still uncertain though - the import price for green hydrogen and the upper limit for photovoltaic installations. To investigate the impact of these two factors, the authors calculate cost optimized climate neutral energy systems while varying the import price from 1.25 €/kg to 5 €/kg with unlimited import volume and the photovoltaic limit from 300 GW to unlimited. In all scenarios, hydrogen plays a significant role. At a medium import price of 3.75 €/kg and photovoltaic limits of 300–900 GW the hydrogen supply is around 1200 to 1300 TWh with import shares varying from 60 to 85%. In most scenarios the electrolysis profile is highly correlated with the photovoltaic power, which leads to full load hours of 1870 h–2770 h.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A climate neutral energy system in Germany will most likely require green hydrogen. Two important factors, that determine whether the hydrogen will be imported or produced locally from renewable energy are still uncertain though - the import price for green hydrogen and the upper limit for photovoltaic installations. To investigate the impact of these two factors, the authors calculate cost optimized climate neutral energy systems while varying the import price from 1.25 €/kg to 5 €/kg with unlimited import volume and the photovoltaic limit from 300 GW to unlimited. In all scenarios, hydrogen plays a significant role. At a medium import price of 3.75 €/kg and photovoltaic limits of 300–900 GW the hydrogen supply is around 1200 to 1300 TWh with import shares varying from 60 to 85%. In most scenarios the electrolysis profile is highly correlated with the photovoltaic power, which leads to full load hours of 1870 h–2770 h.
10.
S Mariotti; K Jäger; M Diederich; M S Härtel; B Li; K Sveinbjörnsson; S Kajari-Schröder; R Peibst; S Albrecht; L Korte; T Wietler
In: Solar RRL, Bd. 6, Ausg. 4, S. 2101066, 2022.
@article{Mariotti2022,
title = {Monolithic Perovskite/Silicon Tandem Solar Cells Fabricated Using Industrial p-Type Polycrystalline Silicon on Oxide/Passivated Emitter and Rear Cell Silicon Bottom Cell Technology},
author = {S Mariotti and K Jäger and M Diederich and M S Härtel and B Li and K Sveinbjörnsson and S Kajari-Schröder and R Peibst and S Albrecht and L Korte and T Wietler},
doi = {10.1002/solr.202101066},
year = {2022},
date = {2022-04-01},
urldate = {2022-02-08},
journal = {Solar RRL},
volume = {6},
issue = {4},
pages = {2101066},
abstract = {Combining a perovskite top cell with a conventional passivated emitter and rear cell (PERC) silicon bottom cell in a monolithically integrated tandem device is an economically attractive solution to boost the power conversion efficiency (PCE) of silicon single-junction technology. Proof-of-concept perovskite/silicon tandem solar cells using high-temperature stable bottom cells featuring a polycrystalline silicon on oxide (POLO) front junction and a PERC-type passivated rear side with local aluminum-p+ contacts are reported. For this PERC/POLO cell, a process flow that is compatible with industrial, mainstream PERC technology is implemented. Top and bottom cells are connected via a tin-doped indium oxide recombination layer. The recombination layer formation on the POLO front junction of the bottom cell is optimized by postdeposition annealing and mitigation of sputter damage. The perovskite top cell is monolithically integrated in a p−i−n junction device architecture. Proof-of-concept tandem cells demonstrate a PCE of up to 21.3%. Based on the experimental findings and supporting optical simulations, major performance enhancements by process and layer optimization are identified and a PCE potential of 29.5% for these perovskite/silicon tandem solar cells with PERC-like bottom cell technology is estimated.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Combining a perovskite top cell with a conventional passivated emitter and rear cell (PERC) silicon bottom cell in a monolithically integrated tandem device is an economically attractive solution to boost the power conversion efficiency (PCE) of silicon single-junction technology. Proof-of-concept perovskite/silicon tandem solar cells using high-temperature stable bottom cells featuring a polycrystalline silicon on oxide (POLO) front junction and a PERC-type passivated rear side with local aluminum-p+ contacts are reported. For this PERC/POLO cell, a process flow that is compatible with industrial, mainstream PERC technology is implemented. Top and bottom cells are connected via a tin-doped indium oxide recombination layer. The recombination layer formation on the POLO front junction of the bottom cell is optimized by postdeposition annealing and mitigation of sputter damage. The perovskite top cell is monolithically integrated in a p−i−n junction device architecture. Proof-of-concept tandem cells demonstrate a PCE of up to 21.3%. Based on the experimental findings and supporting optical simulations, major performance enhancements by process and layer optimization are identified and a PCE potential of 29.5% for these perovskite/silicon tandem solar cells with PERC-like bottom cell technology is estimated.
11.
P Pärisch
Hocheffiziente Wärmepumpenkonzepte mit Wohnungsstationen im Neubau - Projekt WoSta4.0 Vortrag
Leer, Germany, 29.03.2022, (Technikausschuss des vdw Niedersachsen Bremen sowie des VNW Verband Norddeutscher Wohnungsunternehmen).
@misc{Pärisch2022b,
title = {Hocheffiziente Wärmepumpenkonzepte mit Wohnungsstationen im Neubau - Projekt WoSta4.0},
author = {P Pärisch},
year = {2022},
date = {2022-03-29},
address = {Leer, Germany},
note = {Technikausschuss des vdw Niedersachsen Bremen sowie des VNW Verband Norddeutscher Wohnungsunternehmen},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
12.
B Epp; P Pärisch
Gefördert und gefordert: Neue Lösung zur Gebäude-Energieversorgung über PVT-Kollektoren in Verbindung mit Wärmepumpen Vortrag
Leer, Germany, 29.03.2022, (Technikausschuss des vdw Niedersachsen Bremen sowie des VNW Verband Norddeutscher Wohnungsunternehmen).
@misc{Epp2022,
title = {Gefördert und gefordert: Neue Lösung zur Gebäude-Energieversorgung über PVT-Kollektoren in Verbindung mit Wärmepumpen},
author = {B Epp and P Pärisch},
year = {2022},
date = {2022-03-29},
address = {Leer, Germany},
note = {Technikausschuss des vdw Niedersachsen Bremen sowie des VNW Verband Norddeutscher Wohnungsunternehmen},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
13.
M Winter
Performance Degradation and Recovery of Ga-doped Cz-Si Solar Cells Vortrag
Konstanz, Germany, 28.03.2022, (SiliconPV 2022 - 12th International Conference on Silicon Photovoltaics).
@misc{Winter2022,
title = {Performance Degradation and Recovery of Ga-doped Cz-Si Solar Cells},
author = {M Winter},
year = {2022},
date = {2022-03-28},
address = {Konstanz, Germany},
note = {SiliconPV 2022 - 12th International Conference on Silicon Photovoltaics},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
14.
R Niepelt
H2-Wegweiser Niedersachsen Vortrag
Online Event, 15.03.2022, (Wasserstoffnetzwerk Schaumburg).
@misc{Niepelt2022d,
title = {H2-Wegweiser Niedersachsen},
author = {R Niepelt},
year = {2022},
date = {2022-03-15},
address = {Online Event},
note = {Wasserstoffnetzwerk Schaumburg},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
15.
R Niepelt
Wärmepumpen für Niedersachsen: Eine Initiative zur Beschleunigung der Energiewende Vortrag
Online Event, 15.03.2022, (Projektsteuerungskreis Wärmewende Nordwest).
@misc{Niepelt2022c,
title = {Wärmepumpen für Niedersachsen: Eine Initiative zur Beschleunigung der Energiewende},
author = {R Niepelt},
year = {2022},
date = {2022-03-15},
address = {Online Event},
note = {Projektsteuerungskreis Wärmewende Nordwest},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
16.
A Dittrich; F Heinemeyer; C Xu; R Reineke-Koch
In: AIP Advances, Bd. 12, Nr. 3, S. 035118, 2022.
@article{Dittrich2022,
title = {Realization of a cost-effective thermochromic solar absorber with a high emittance change based on VO2 and an infrared transparent intermediate layer},
author = {A Dittrich and F Heinemeyer and C Xu and R Reineke-Koch},
doi = {10.1063/5.0063702},
year = {2022},
date = {2022-03-01},
urldate = {2022-01-01},
journal = {AIP Advances},
volume = {12},
number = {3},
pages = {035118},
abstract = {In this study, we present a thermochromic solar absorber coating that reaches a high thermal emittance change by using a thin, optically switching VOx film located on an infrared transparent interlayer (spacer) of Si or Ge with an optical thickness of λ/4 (for λ = 7 μm). Using this so-called “lambda/4-concept,” temperature-dependent reflection measurements in the spectral range between 2500 and 50 000 nm from an absorber with a 450 nm Si spacer and a VOx film oxidized from a 30-nm-thick V display an overall increase in emittance from ε(25 °C) = 12.2% to ε(150 °C) = 55.1%, resulting in a change of Δε = 42.9%. In addition, using an absorber with a 400 nm Ge spacer in combination with a VOx film oxidized from 17.5-nm-thick V, an increase in emittance from ε(25 °C) = 8.2% to ε(150 °C) = 49.2% with a change of Δε = 41.0% was achieved. In addition, the optical properties of Ge and Si thin films over a wide spectral range of 250–38 000 nm were determined using spectroscopic ellipsometry. Using this optical data and a simple optical model of the VOx film, reflectance simulations could be performed by using the ellipsometry analysis software WVASE©. It was shown by x-ray diffraction measurements that the optically switching VOx films oxidized from V in a belt furnace consist of the VO2 and the V2O5 phases. Using scanning electron microscopy images, the surface morphology of optically switching VOx films was compared with over-oxidized VOx films. A correlation between the surface morphology and the crystalline phases was revealed and applied to search for the optimal furnace parameters. This method could significantly reduce the time cost to achieve optically switching VOx coatings using an oxidation process.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In this study, we present a thermochromic solar absorber coating that reaches a high thermal emittance change by using a thin, optically switching VOx film located on an infrared transparent interlayer (spacer) of Si or Ge with an optical thickness of λ/4 (for λ = 7 μm). Using this so-called “lambda/4-concept,” temperature-dependent reflection measurements in the spectral range between 2500 and 50 000 nm from an absorber with a 450 nm Si spacer and a VOx film oxidized from a 30-nm-thick V display an overall increase in emittance from ε(25 °C) = 12.2% to ε(150 °C) = 55.1%, resulting in a change of Δε = 42.9%. In addition, using an absorber with a 400 nm Ge spacer in combination with a VOx film oxidized from 17.5-nm-thick V, an increase in emittance from ε(25 °C) = 8.2% to ε(150 °C) = 49.2% with a change of Δε = 41.0% was achieved. In addition, the optical properties of Ge and Si thin films over a wide spectral range of 250–38 000 nm were determined using spectroscopic ellipsometry. Using this optical data and a simple optical model of the VOx film, reflectance simulations could be performed by using the ellipsometry analysis software WVASE©. It was shown by x-ray diffraction measurements that the optically switching VOx films oxidized from V in a belt furnace consist of the VO2 and the V2O5 phases. Using scanning electron microscopy images, the surface morphology of optically switching VOx films was compared with over-oxidized VOx films. A correlation between the surface morphology and the crystalline phases was revealed and applied to search for the optimal furnace parameters. This method could significantly reduce the time cost to achieve optically switching VOx coatings using an oxidation process.
17.
T Ohrdes
Erneuerbar betriebene Wärmepumpen - eine Herausforderung für die Stromnetze? Vortrag
Online Event, 22.02.2022, (1. Niedersächsischer Wärmepumpentag).
@misc{Ohrdes2022,
title = {Erneuerbar betriebene Wärmepumpen - eine Herausforderung für die Stromnetze?},
author = {T Ohrdes},
year = {2022},
date = {2022-02-22},
address = {Online Event},
note = {1. Niedersächsischer Wärmepumpentag},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
18.
R Niepelt
Wärmepumpenforschung als Motor der Energiewende Vortrag
Online Event, 22.02.2022, (1. Niedersächsischer Wärmepumpentag).
@misc{Niepelt2022,
title = {Wärmepumpenforschung als Motor der Energiewende},
author = {R Niepelt},
year = {2022},
date = {2022-02-22},
address = {Online Event},
note = {1. Niedersächsischer Wärmepumpentag},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
19.
P Pärisch
Wichtige Eigenschaften von zentralen Durchfluss-Trinkwassererwärmern für solare Kombisysteme Vortrag
Online Event, 21.02.2022, (Fokustreffen Zukunft der Trink(warm)wasserinstallation und –bereitstellung; Begleitforschung Energiewendebauen).
@misc{Pärisch2022,
title = {Wichtige Eigenschaften von zentralen Durchfluss-Trinkwassererwärmern für solare Kombisysteme},
author = {P Pärisch},
year = {2022},
date = {2022-02-21},
address = {Online Event},
note = {Fokustreffen Zukunft der Trink(warm)wasserinstallation und –bereitstellung; Begleitforschung Energiewendebauen},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
20.
R Peibst; F Haase; B Min; C Hollemann; T Brendemühl; K Bothe; R Brendel
On the chances and challenges of combining electron-collecting nPOLO and hole-collecting Al-p+ contacts in highly efficient p-type c-Si solar cells Artikel Geplante Veröffentlichung
In: Progress in Photovoltaics: Research and Applications, Geplante Veröffentlichung.
@article{Peibst2022b,
title = {On the chances and challenges of combining electron-collecting nPOLO and hole-collecting Al-p+ contacts in highly efficient p-type c-Si solar cells},
author = {R Peibst and F Haase and B Min and C Hollemann and T Brendemühl and K Bothe and R Brendel},
doi = {10.1002/pip.3545},
year = {2022},
date = {2022-02-21},
urldate = {2022-02-21},
journal = {Progress in Photovoltaics: Research and Applications},
abstract = {ISFH is following a distinct cell development roadmap, which comprises—as a short-term concept—the combination of an n-type doped electron-collecting poly-Si on oxide (POLO) junction with an Al-alloyed p+ junction for hole collection. This combination can be integrated either in front- and back-contacted back junction cells (POLO-BJ) or in interdigitated back-contacted cells (POLO-IBC). Here, we present recent progress with these two cell concepts. We report on a certified M2-sized 22.9% efficient POLO-BJ cell with a temperature coefficient TCη of only −(0.3 ± 0.02) %rel/K and a certified 23.7% (4 cm2 d.a.) efficient POLO-IBC cell. We discuss various specific conceptual aspects of this technology and present a simulation-based sensitivity analysis for quantities related to the quality of the hole-collecting alloyed Al-p+ junction which are subject to continuous improvement and thus hard to predict exactly. We report that the measured pseudo fill factor values decrease more due to metallization than would be expected from recombination in the metallized regions with an ideality factor of one only. The gap to pseudo fill factor values that are theoretically achievable at the respective open-circuit voltages is 1.1%abs (Ga-doped wafer) for POLO-IBC and 1.4%abs (B-doped wafer) to 2%abs (Ga-doped wafer) for POLO-BJ. With an embedded blocking layer for Ag crystallites in the poly-Si, we present a concept to reduce this gap.},
keywords = {},
pubstate = {forthcoming},
tppubtype = {article}
}
ISFH is following a distinct cell development roadmap, which comprises—as a short-term concept—the combination of an n-type doped electron-collecting poly-Si on oxide (POLO) junction with an Al-alloyed p+ junction for hole collection. This combination can be integrated either in front- and back-contacted back junction cells (POLO-BJ) or in interdigitated back-contacted cells (POLO-IBC). Here, we present recent progress with these two cell concepts. We report on a certified M2-sized 22.9% efficient POLO-BJ cell with a temperature coefficient TCη of only −(0.3 ± 0.02) %rel/K and a certified 23.7% (4 cm2 d.a.) efficient POLO-IBC cell. We discuss various specific conceptual aspects of this technology and present a simulation-based sensitivity analysis for quantities related to the quality of the hole-collecting alloyed Al-p+ junction which are subject to continuous improvement and thus hard to predict exactly. We report that the measured pseudo fill factor values decrease more due to metallization than would be expected from recombination in the metallized regions with an ideality factor of one only. The gap to pseudo fill factor values that are theoretically achievable at the respective open-circuit voltages is 1.1%abs (Ga-doped wafer) for POLO-IBC and 1.4%abs (B-doped wafer) to 2%abs (Ga-doped wafer) for POLO-BJ. With an embedded blocking layer for Ag crystallites in the poly-Si, we present a concept to reduce this gap.