1.
B Chhugani; P Pärisch; S Helmling; F Giovannetti
In: Solar Energy Advances, Bd. 3, S. 100031, 2023, ISSN: 2667-1131.
@article{Chhugani2023,
title = {Comparison of PVT - heat pump systems with reference systems for the energy supply of a single-family house},
author = {B Chhugani and P Pärisch and S Helmling and F Giovannetti},
doi = {10.1016/j.seja.2022.100031},
issn = {2667-1131},
year = {2023},
date = {2023-01-01},
urldate = {2023-01-01},
journal = {Solar Energy Advances},
volume = {3},
pages = {100031},
abstract = {Photovoltaic - Thermal (PVT) collectors convert solar radiation into useful heat and electricity simultaneously, and with the same PV area, higher solar energy is harvested; hence PVT can be a key technology for the future supply of buildings. The paper compares different heat supply systems for a single-family house, focusing on PVT and heat pump systems. The results show that the PVT - heat pump achieves a higher seasonal performance factor (SPF) than an air-source heat pump. With 30 m² efficient PVT and the heat pump achieves ≈14% higher SPFbStthan air source heat pump (3.82 for PVT - brine water heat pump to 3.29 air-source heat pump). With the same PVT area, SPFbSt(Grid) including self-consumed PVT electricity by the heat pump system, reaches 4.3 with a demand-based control strategy and 4.97 with a PV-based control strategy. Furthermore, results confirm that by combining PVT collectors and ground-source heat pumps with borehole heat exchangers (BHE), BHEs can be dimensioned 30 to 35% smaller without impacting the system efficiency. The paper also presents the monitoring results of one of the demonstration plants under investigation. The experimental results confirm the good performance of the PVT as a single heat source for heat pumps, with achieved SPFbSt of 3.1 (with 16 m² of the same efficient PVT).},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Photovoltaic - Thermal (PVT) collectors convert solar radiation into useful heat and electricity simultaneously, and with the same PV area, higher solar energy is harvested; hence PVT can be a key technology for the future supply of buildings. The paper compares different heat supply systems for a single-family house, focusing on PVT and heat pump systems. The results show that the PVT - heat pump achieves a higher seasonal performance factor (SPF) than an air-source heat pump. With 30 m² efficient PVT and the heat pump achieves ≈14% higher SPFbStthan air source heat pump (3.82 for PVT - brine water heat pump to 3.29 air-source heat pump). With the same PVT area, SPFbSt(Grid) including self-consumed PVT electricity by the heat pump system, reaches 4.3 with a demand-based control strategy and 4.97 with a PV-based control strategy. Furthermore, results confirm that by combining PVT collectors and ground-source heat pumps with borehole heat exchangers (BHE), BHEs can be dimensioned 30 to 35% smaller without impacting the system efficiency. The paper also presents the monitoring results of one of the demonstration plants under investigation. The experimental results confirm the good performance of the PVT as a single heat source for heat pumps, with achieved SPFbSt of 3.1 (with 16 m² of the same efficient PVT).
2.
M A Green; E D Dunlop; G Siefer; M Yoshita; N Kopidakis; K Bothe; X Hao
Solar cell efficiency tables (Version 61) Artikel
In: Progress in Photovoltaics: Research and Applications, Bd. 31, Nr. 1, S. 3-16, 2023.
@article{Green2023,
title = {Solar cell efficiency tables (Version 61)},
author = {M A Green and E D Dunlop and G Siefer and M Yoshita and N Kopidakis and K Bothe and X Hao},
doi = {10.1002/pip.3646},
year = {2023},
date = {2023-01-01},
urldate = {2023-01-01},
journal = {Progress in Photovoltaics: Research and Applications},
volume = {31},
number = {1},
pages = {3-16},
abstract = {Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined, and new entries since July 2022 are reviewed. Graphs showing progress with each cell technology over the 30-year history of the tables are also included plus an updated list of designated test centres.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined, and new entries since July 2022 are reviewed. Graphs showing progress with each cell technology over the 30-year history of the tables are also included plus an updated list of designated test centres.
3.
T Dullweber; V Mertens; M Stöhr; J Langlois; L Mettner; U Baumann; F Haase; R Brendel; J Libal; A Hähnel; A Müller; V Naumann; A Vogt; N Ambrosius; T Pernau; H Haverkamp
Towards Cost-Effective High-Efficiency POLO IBC Solar Cells with Minimal Conversion Invest for Existing PERC+ Production Lines Konferenzbeitrag
In: Proceedings of the 8th World Conference on Photovoltaic Energy Conversion, S. 35 - 39, Milano, Italy, 2022.
@inproceedings{Dullweber2022b,
title = {Towards Cost-Effective High-Efficiency POLO IBC Solar Cells with Minimal Conversion Invest for Existing PERC+ Production Lines},
author = {T Dullweber and V Mertens and M Stöhr and J Langlois and L Mettner and U Baumann and F Haase and R Brendel and J Libal and A Hähnel and A Müller and V Naumann and A Vogt and N Ambrosius and T Pernau and H Haverkamp},
doi = {10.4229/WCPEC-82022-1AO.6.5},
year = {2022},
date = {2022-12-12},
booktitle = {Proceedings of the 8th World Conference on Photovoltaic Energy Conversion},
pages = {35 - 39},
address = {Milano, Italy},
abstract = {In this paper, we report a novel manufacturing process sequence for POLO IBC solar cells applying a local PECVD SiOxNy/n-a-Si deposition through a glass shadow mask to form the structured carrier selective n-polySi layer in one process step. Using a lab-type single-wafer PECVD tool, the POLO IBC precursors without metal contacts exhibit an excellent implied Voc of 741 mV. A TEM analysis confirms that the N2O in-situ plasma oxidation indeed incorporates N in the interfacial SiOxNy layer which could facilitate the excellent firing stable surface passivation. The laser contact openings and screen-printed Al and Ag rear contacts were successfully aligned to the shadow mask features within ± 20 µm precision. Fully processed POLO IBC solar cells on M2-sized Ga-doped Cz wafers exhibit conversion efficiencies of up to 23.0% with Voc=708 mV, Jsc =41.2 mA/cm2 and FF=78.7%. We attribute the 33 mV difference between implied Voc and Voc to additional J0 contributions of the Ag and Al metal contacts which is subject to future improvements. As next step towards POLO IBC mass production readiness, we transfer the PECVD SiOxNy/n-a-Si process through shadow masks from the single-wafer lab-tool to a massproduction c.plasma PECVD tool from centrotherm, which is installed at the ISFH SolarTeC. Test wafers with double-sided in-situ PECVD SiOxNy/n-a-Si deposition reveal an excellent J0 = 3 fA/cm2 after annealing, SiN capping and firing. We apply the glass shadow mask in the industrial c.plasma PECVD tool in combination with the PECVD SiOxNy/n-a-Si deposition. The first POLO IBC solar cells processed with the c.plasma tool with shadow masks achieve conversion efficiencies up to 22.3% and average Voc values of 710 mV. In the future, we aim at further increasing the conversion efficiency towards 25% and implementing an automated shadow mask loading into the industrial c.plasma tool. },
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
In this paper, we report a novel manufacturing process sequence for POLO IBC solar cells applying a local PECVD SiOxNy/n-a-Si deposition through a glass shadow mask to form the structured carrier selective n-polySi layer in one process step. Using a lab-type single-wafer PECVD tool, the POLO IBC precursors without metal contacts exhibit an excellent implied Voc of 741 mV. A TEM analysis confirms that the N2O in-situ plasma oxidation indeed incorporates N in the interfacial SiOxNy layer which could facilitate the excellent firing stable surface passivation. The laser contact openings and screen-printed Al and Ag rear contacts were successfully aligned to the shadow mask features within ± 20 µm precision. Fully processed POLO IBC solar cells on M2-sized Ga-doped Cz wafers exhibit conversion efficiencies of up to 23.0% with Voc=708 mV, Jsc =41.2 mA/cm2 and FF=78.7%. We attribute the 33 mV difference between implied Voc and Voc to additional J0 contributions of the Ag and Al metal contacts which is subject to future improvements. As next step towards POLO IBC mass production readiness, we transfer the PECVD SiOxNy/n-a-Si process through shadow masks from the single-wafer lab-tool to a massproduction c.plasma PECVD tool from centrotherm, which is installed at the ISFH SolarTeC. Test wafers with double-sided in-situ PECVD SiOxNy/n-a-Si deposition reveal an excellent J0 = 3 fA/cm2 after annealing, SiN capping and firing. We apply the glass shadow mask in the industrial c.plasma PECVD tool in combination with the PECVD SiOxNy/n-a-Si deposition. The first POLO IBC solar cells processed with the c.plasma tool with shadow masks achieve conversion efficiencies up to 22.3% and average Voc values of 710 mV. In the future, we aim at further increasing the conversion efficiency towards 25% and implementing an automated shadow mask loading into the industrial c.plasma tool.
4.
B Min; L Nasebandt; C Hollemann; D Bredemeier; L Thiemann; T Brendemühl; K Bothe; R Peibst; R Brendel
23.1%-Efficient POLO Back Junction Solar Cells Konferenzbeitrag
In: Proceedings of the 8th World Conference on Photovoltaic Energy Conversion, S. 107 - 109, Milano, Italy, 2022.
@inproceedings{Min2022c,
title = {23.1%-Efficient POLO Back Junction Solar Cells},
author = {B Min and L Nasebandt and C Hollemann and D Bredemeier and L Thiemann and T Brendemühl and K Bothe and R Peibst and R Brendel},
doi = {10.4229/WCPEC-82022-1CV.2.13},
year = {2022},
date = {2022-12-12},
booktitle = {Proceedings of the 8th World Conference on Photovoltaic Energy Conversion},
pages = {107 - 109},
address = {Milano, Italy},
abstract = {This work presents the recent progress of all screen-printed p-type back junction (BJ) solar cells featuring Al-front contacts and passivating polysilicon on oxide (POLO) rear contacts. We achieve a new best cell efficiency of 23.1 % on full M2 Cz wafers as independently confirmed by ISFH CalTeC in Germany. We mainly improve the fill factor of our POLO BJ solar cells by increasing the number of Ag fingers at the rear side. This increase of Ag rear contacts does not affect the open-circuit voltage because we apply an Ag paste with less aggressive chemistry, hence the recombination losses at Ag contacts are negligibly small. In addition, we analyze the temperature-dependent cell performance of an in-house fabricated POLO BJ solar cell. We extract −0.2953 %/K as the efficiency temperature coefficient (TC) of the investigated POLO BJ solar cell, which is superior to −0.36 %/K of PERC solar cells in the literature [1], mainly due to the higher open-circuit voltage TC of the POLO BJ device, that amount to −0.2462 %/K. Our study indicates that particular high annual yields are to be expected from POLO BJ cells in the regions with high temperatures such as Middle East and North Africa. },
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
This work presents the recent progress of all screen-printed p-type back junction (BJ) solar cells featuring Al-front contacts and passivating polysilicon on oxide (POLO) rear contacts. We achieve a new best cell efficiency of 23.1 % on full M2 Cz wafers as independently confirmed by ISFH CalTeC in Germany. We mainly improve the fill factor of our POLO BJ solar cells by increasing the number of Ag fingers at the rear side. This increase of Ag rear contacts does not affect the open-circuit voltage because we apply an Ag paste with less aggressive chemistry, hence the recombination losses at Ag contacts are negligibly small. In addition, we analyze the temperature-dependent cell performance of an in-house fabricated POLO BJ solar cell. We extract −0.2953 %/K as the efficiency temperature coefficient (TC) of the investigated POLO BJ solar cell, which is superior to −0.36 %/K of PERC solar cells in the literature [1], mainly due to the higher open-circuit voltage TC of the POLO BJ device, that amount to −0.2462 %/K. Our study indicates that particular high annual yields are to be expected from POLO BJ cells in the regions with high temperatures such as Middle East and North Africa.
5.
M Herz; G Friesen; U Jahn; M Köntges; S Lindig; D Moser
Identify, Analyse, Mitigate – Quantification of Technical Risks in PV Power Systems Konferenzbeitrag
In: Proceedings of the 8th World Conference on Photovoltaic Energy Conversion, S. 1105 - 1111, Milano, Italy, 2022.
@inproceedings{Herz2022b,
title = {Identify, Analyse, Mitigate – Quantification of Technical Risks in PV Power Systems},
author = {M Herz and G Friesen and U Jahn and M Köntges and S Lindig and D Moser},
doi = {10.4229/WCPEC-82022-4DO.4.3},
year = {2022},
date = {2022-12-12},
booktitle = {Proceedings of the 8th World Conference on Photovoltaic Energy Conversion},
pages = {1105 - 1111},
address = {Milano, Italy},
abstract = {Technical risks are important criteria to consider when investing in new and existing PV installations. Quantitative knowledge of these risks is one of the key factors for the different stakeholders, such as asset managers, banks or project developers, to make reliable business decisions before and during the operation of their PV assets. Within the IEA PVPS Task 13 Expert Group, we aim to increase the knowledge on methodologies to assess technical risks and mitigation measures in terms of economic impact and effectiveness. The developed outline provides a reproducible and transparent technique to manage the complexity of risk analysis and processing in order to establish a common practice for professional risk assessment. Semi-quantitative and quantitative methodologies are introduced to assess technical risks in PV power systems and provide examples of common technical risks described and rated in the new created PV failure fact sheets (PVFS). Besides the PVFS based on expert knowledge and expert opinion, an update on the statistics of the PV failure degradation survey is given. With the knowledge acquired and data collected, the risk and cost-benefit analysis is demonstrated in a case study that shows methods for prioritizing decisions from an economic perspective and provided important results for risk managing strategies.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Technical risks are important criteria to consider when investing in new and existing PV installations. Quantitative knowledge of these risks is one of the key factors for the different stakeholders, such as asset managers, banks or project developers, to make reliable business decisions before and during the operation of their PV assets. Within the IEA PVPS Task 13 Expert Group, we aim to increase the knowledge on methodologies to assess technical risks and mitigation measures in terms of economic impact and effectiveness. The developed outline provides a reproducible and transparent technique to manage the complexity of risk analysis and processing in order to establish a common practice for professional risk assessment. Semi-quantitative and quantitative methodologies are introduced to assess technical risks in PV power systems and provide examples of common technical risks described and rated in the new created PV failure fact sheets (PVFS). Besides the PVFS based on expert knowledge and expert opinion, an update on the statistics of the PV failure degradation survey is given. With the knowledge acquired and data collected, the risk and cost-benefit analysis is demonstrated in a case study that shows methods for prioritizing decisions from an economic perspective and provided important results for risk managing strategies.
6.
R Peibst; C Schwarz; Y Larionova; S Wolter; M Rienäcker; T Wietler; M Diederich; R Brendel
Interface between Poly-Si on Oxide Passivated Si Bottom and Perovskite Top Cells – Search for the Leanest and Best Working Layer Stack Konferenzbeitrag
In: Proceedings of the 8th World Conference on Photovoltaic Energy Conversion, S. 255 - 259, Milano, Italy, 2022.
@inproceedings{R Peibst2022,
title = {Interface between Poly-Si on Oxide Passivated Si Bottom and Perovskite Top Cells – Search for the Leanest and Best Working Layer Stack},
author = {R Peibst and C Schwarz and Y Larionova and S Wolter and M Rienäcker and T Wietler and M Diederich and R Brendel },
doi = {10.4229/WCPEC-82022-2CO.1.2},
year = {2022},
date = {2022-12-12},
urldate = {2022-12-12},
booktitle = {Proceedings of the 8th World Conference on Photovoltaic Energy Conversion},
pages = {255 - 259},
address = {Milano, Italy},
abstract = {Regarding the interface between Si bottom cells with poly-Si on oxide (POLO) junctions as the uppermost layer and the lowest layer of a perovskite (Pk) top cell (i.e., the hole-selective layer HTL in pin configuration), many questions are still open, including the one which layers are actually required for low-resistive subcell interconnection. In this work, we compare recombination-layer (RL) and tunneling junction (TJ) - based subcell interconnection schemes, namely spiro-TTB/n+ poly-Si, spiro-TTB/p+ poly-Si/n+ poly-Si, and spiro-TTB/ITO/n+ poly-Si. The first is – to our knowledge for the first time – investigated experimentally. We prepare dedicated Pk/Si test structures, which are opaque co-evaporated MAPbI3 top cells on Si substrates with the uppermost layers of interest. DarkIV and frequency-dependent impedance measurements are applied. We reveal an upper limit for the contact resistance of 14 mΩcm2 for the p+ poly-Si / n poly-Si tunnel junction with Cox&Strack measurements. We observe a reduction of the current densities measured on our Pk/Si test structures upon biasing at more than 1 V, that stabilizes at a factor of ~1/300 for the spiro-TTB/ITO and of ~ 1/10 for both spiro-TTB/poly-Si interfaces as compared to the initial measurement. After stabilization, our IV measurements show that the spiro-TTB/n+ poly-Si recombination junction conducts comparable current densities as the spiro-TTB/p+ poly-Si interface. Within a framework of a three-element equivalent circuit for impedance measurements, the spiro-TTB/X interface affects the voltage dependent parallel resistance. The comparable current densities for the spiro-TTB/n+ poly-Si and the spiro-TTB/p+ poly-Si interface gives hope that n+-type poly-Si can indeed work as a recombination layer itself, although we did not succeed in a quantification of the specific resistance of the spiro-TTB/X interface. This indication has to be verified on full tandem cells. },
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Regarding the interface between Si bottom cells with poly-Si on oxide (POLO) junctions as the uppermost layer and the lowest layer of a perovskite (Pk) top cell (i.e., the hole-selective layer HTL in pin configuration), many questions are still open, including the one which layers are actually required for low-resistive subcell interconnection. In this work, we compare recombination-layer (RL) and tunneling junction (TJ) - based subcell interconnection schemes, namely spiro-TTB/n+ poly-Si, spiro-TTB/p+ poly-Si/n+ poly-Si, and spiro-TTB/ITO/n+ poly-Si. The first is – to our knowledge for the first time – investigated experimentally. We prepare dedicated Pk/Si test structures, which are opaque co-evaporated MAPbI3 top cells on Si substrates with the uppermost layers of interest. DarkIV and frequency-dependent impedance measurements are applied. We reveal an upper limit for the contact resistance of 14 mΩcm2 for the p+ poly-Si / n poly-Si tunnel junction with Cox&Strack measurements. We observe a reduction of the current densities measured on our Pk/Si test structures upon biasing at more than 1 V, that stabilizes at a factor of ~1/300 for the spiro-TTB/ITO and of ~ 1/10 for both spiro-TTB/poly-Si interfaces as compared to the initial measurement. After stabilization, our IV measurements show that the spiro-TTB/n+ poly-Si recombination junction conducts comparable current densities as the spiro-TTB/p+ poly-Si interface. Within a framework of a three-element equivalent circuit for impedance measurements, the spiro-TTB/X interface affects the voltage dependent parallel resistance. The comparable current densities for the spiro-TTB/n+ poly-Si and the spiro-TTB/p+ poly-Si interface gives hope that n+-type poly-Si can indeed work as a recombination layer itself, although we did not succeed in a quantification of the specific resistance of the spiro-TTB/X interface. This indication has to be verified on full tandem cells.
7.
H Schulte-Huxel; R Witteck; S Blankemeyer; M Köntges
From Three Terminal Tandem Solar Cells to Modules Vortrag
Boston, USA, 07.12.2022, (2022 MRS Fall Meeting & Exhibit).
@misc{Schulte-Huxel2022d,
title = {From Three Terminal Tandem Solar Cells to Modules},
author = {H Schulte-Huxel and R Witteck and S Blankemeyer and M Köntges},
year = {2022},
date = {2022-12-07},
address = {Boston, USA},
note = {2022 MRS Fall Meeting & Exhibit},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
8.
H Genath; J Norberg; B Wolpensinger; H J Osten
Investigation of the temperature stability of germanium-rich SiGe layers on Si(111) substrates Artikel
In: Thin Solid Films, Bd. 763, S. 139561, 2022, ISSN: 0040-6090.
@article{Genath2022,
title = {Investigation of the temperature stability of germanium-rich SiGe layers on Si(111) substrates},
author = {H Genath and J Norberg and B Wolpensinger and H J Osten},
doi = {10.1016/j.tsf.2022.139561},
issn = {0040-6090},
year = {2022},
date = {2022-12-01},
urldate = {2022-12-01},
journal = {Thin Solid Films},
volume = {763},
pages = {139561},
abstract = {In this work, we investigated fully relaxed SiGe and pure Ge layers on Si(111) substrates, regarding their temperature stability. The layers were annealed at various temperatures up to 650 °C directly after growth. The Ge content of the Si1−xGex layers was varied between 0.6 and 1. We investigated effects due to surface segregation of Ge in the SiGe layers. During heat treatment, different surface reconstructions were observed. The SiGe layers remained smooth with a root-mean square surface roughness below 0.5 nm up to temperatures of 500 °C and a 7 × 7 surface reconstruction was seen. Annealing at higher temperatures corresponding to a 7 × 7–“1 × 1” phase transition, the surface roughness increased to more than 2 nm and island formation was observed. We measured the in-plane lattice constant of the surface as a function of temperature and confirmed a strong effect of Ge segregation on the surface strain. The Ge accumulation at the surface was confirmed by angle-resolved X-ray photoelectron spectroscopy. The high adatom density of the “1 × 1” reconstruction in combination with compressive strain led to island nucleation when cooling down. Pure Ge layers remained smooth even after annealing up to 650 °C.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In this work, we investigated fully relaxed SiGe and pure Ge layers on Si(111) substrates, regarding their temperature stability. The layers were annealed at various temperatures up to 650 °C directly after growth. The Ge content of the Si1−xGex layers was varied between 0.6 and 1. We investigated effects due to surface segregation of Ge in the SiGe layers. During heat treatment, different surface reconstructions were observed. The SiGe layers remained smooth with a root-mean square surface roughness below 0.5 nm up to temperatures of 500 °C and a 7 × 7 surface reconstruction was seen. Annealing at higher temperatures corresponding to a 7 × 7–“1 × 1” phase transition, the surface roughness increased to more than 2 nm and island formation was observed. We measured the in-plane lattice constant of the surface as a function of temperature and confirmed a strong effect of Ge segregation on the surface strain. The Ge accumulation at the surface was confirmed by angle-resolved X-ray photoelectron spectroscopy. The high adatom density of the “1 × 1” reconstruction in combination with compressive strain led to island nucleation when cooling down. Pure Ge layers remained smooth even after annealing up to 650 °C.
9.
T Wang; F Ehre; T P Weiss; B Veith-Wolf; V Titova; N Valle; M Melchiorre; O Ramírez; J Schmidt; S Siebentritt
Diode Factor in Solar Cells with Metastable Defects and Back Contact Recombination Artikel
In: Advanced Energy Materials, Bd. 12, Ausg. 44, S. 2202076, 2022.
@article{Wang2022,
title = {Diode Factor in Solar Cells with Metastable Defects and Back Contact Recombination},
author = {T Wang and F Ehre and T P Weiss and B Veith-Wolf and V Titova and N Valle and M Melchiorre and O Ramírez and J Schmidt and S Siebentritt},
doi = {10.1002/aenm.202202076},
year = {2022},
date = {2022-11-24},
urldate = {2022-09-22},
journal = {Advanced Energy Materials},
volume = {12},
issue = {44},
pages = {2202076},
abstract = {To achieve a high fill factor, a small diode factor close to 1 is essential. The optical diode factor determined by photoluminescence is the diode factor from the neutral zone of the solar cell and thus a lower bound for the diode factor. Due to metastable defects transitions, the optical diode factor is higher than 1 even at low excitation. Here, the influence of the backside recombination and the doping level on the optical diode factor are studied. First, photoluminescence and solar cell capacitance simulator (SCAPS) simulations are used to determine the back surface recombination velocity of Cu(In, Ga)Se2 with various back contacts and different doping levels. Then, experimental results and simulations show that both back surface recombination and high doping density reduce the optical diode factor. The back surface recombination reduces the optical diode factor with undesirable extra nonradiative recombination. The smaller value achieved by higher doping can increase quasi-Fermi level splitting at the same time. The simulations show that the back surface recombination reduces the optical diode factor due to an illumination-dependent recombination rate. In addition, a higher majority carrier doping reduces the influence of majority carrier gain from metastable defect transitions, thus reducing the optical diode factor.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
To achieve a high fill factor, a small diode factor close to 1 is essential. The optical diode factor determined by photoluminescence is the diode factor from the neutral zone of the solar cell and thus a lower bound for the diode factor. Due to metastable defects transitions, the optical diode factor is higher than 1 even at low excitation. Here, the influence of the backside recombination and the doping level on the optical diode factor are studied. First, photoluminescence and solar cell capacitance simulator (SCAPS) simulations are used to determine the back surface recombination velocity of Cu(In, Ga)Se2 with various back contacts and different doping levels. Then, experimental results and simulations show that both back surface recombination and high doping density reduce the optical diode factor. The back surface recombination reduces the optical diode factor with undesirable extra nonradiative recombination. The smaller value achieved by higher doping can increase quasi-Fermi level splitting at the same time. The simulations show that the back surface recombination reduces the optical diode factor due to an illumination-dependent recombination rate. In addition, a higher majority carrier doping reduces the influence of majority carrier gain from metastable defect transitions, thus reducing the optical diode factor.
10.
V Mertens; U Baumann; S Dorn; R Brendel; N Ambrosius; T Pernau; H Haverkamp; J Vollmer; T Dullweber
Advances in POLO IBC solar cells with shadow mask process Vortrag
Konstanz, Germany, 21.11.2022, (10th workshop on Back contact solar cell and module technology (BCworkshop2022)).
@misc{Mertens2022b,
title = {Advances in POLO IBC solar cells with shadow mask process},
author = {V Mertens and U Baumann and S Dorn and R Brendel and N Ambrosius and T Pernau and H Haverkamp and J Vollmer and T Dullweber},
year = {2022},
date = {2022-11-21},
urldate = {2022-11-21},
address = {Konstanz, Germany},
note = {10th workshop on Back contact solar cell and module technology (BCworkshop2022)},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
11.
G Wetzel; L Salomon; J Krügener; R Peibst
Assessment of required MPPT speed based on measured transient irradiance and dynamic electrical modelling for VIPV applications Vortrag
Nagoya, Japan, 17.11.2022, (33rd International Photovoltaic Science and Engineering Conference (PVSEC-33)).
@misc{Wetzel2022b,
title = {Assessment of required MPPT speed based on measured transient irradiance and dynamic electrical modelling for VIPV applications},
author = {G Wetzel and L Salomon and J Krügener and R Peibst},
year = {2022},
date = {2022-11-17},
address = {Nagoya, Japan},
note = {33rd International Photovoltaic Science and Engineering Conference (PVSEC-33)},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
12.
T Dullweber; V Mertens; U Baumann; T Kosuke; M Dhamrin; R Brendel
High-efficiency low-cost IBC upgrade of existing PERC+ production lines: the POLO IBC with PECVD shadow mask approach Vortrag
Nagoya, Japan, 16.11.2022, (33rd International Photovoltaic Science and Engineering Conference (PVSEC-33)).
@misc{Dullweber2022c,
title = {High-efficiency low-cost IBC upgrade of existing PERC+ production lines: the POLO IBC with PECVD shadow mask approach},
author = {T Dullweber and V Mertens and U Baumann and T Kosuke and M Dhamrin and R Brendel },
year = {2022},
date = {2022-11-16},
address = {Nagoya, Japan},
note = {33rd International Photovoltaic Science and Engineering Conference (PVSEC-33)},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
13.
H Schulte-Huxel; R Witteck; S Blankemeyer; M Köntges
Optimal interconnection of three-terminal tandem solar cells Artikel Geplante Veröffentlichung
In: Progress in Photovoltaics: Research and Applications, Geplante Veröffentlichung.
@article{Schulte-Huxel2022c,
title = {Optimal interconnection of three-terminal tandem solar cells},
author = {H Schulte-Huxel and R Witteck and S Blankemeyer and M Köntges},
doi = {10.1002/pip.3643},
year = {2022},
date = {2022-11-13},
urldate = {2022-11-13},
journal = {Progress in Photovoltaics: Research and Applications},
abstract = {Abstract Three-terminal (3T) tandem solar cells require an adapted module integration scheme in order to explore their full efficiency potential. The three terminals allow to extract the power of the top and bottom cell separately. In a cell string, the wide bandgap top cells are interconnected in parallel to multiple bottom cells resulting in a parallel/series interconnection. This interconnection scheme affects the operation of the subcells, the resulting current path between the subcells, the layout of the cell interconnects, and the system level. Here, we analyze by simulations and experiments the aspects of the module integration of series- and reverse-connected 3T cells with their practical impact on module processes and performance as well as the effect of varying voltage ratios on the string-end losses. If the subcells are connected in series, the module integration requires insulation layers and significantly longer interconnects compared to devices with reverse-connected subcells. Tandem devices with a reverse connection and a voltage ratio between top and bottom cell of 2:1 allow a lean interconnection design and low integration losses. We present an approach for the integration of bypass diodes for the protection against shading effects that allow to minimize string-end and shading losses for a system of modules featuring 3T cells.},
keywords = {},
pubstate = {forthcoming},
tppubtype = {article}
}
Abstract Three-terminal (3T) tandem solar cells require an adapted module integration scheme in order to explore their full efficiency potential. The three terminals allow to extract the power of the top and bottom cell separately. In a cell string, the wide bandgap top cells are interconnected in parallel to multiple bottom cells resulting in a parallel/series interconnection. This interconnection scheme affects the operation of the subcells, the resulting current path between the subcells, the layout of the cell interconnects, and the system level. Here, we analyze by simulations and experiments the aspects of the module integration of series- and reverse-connected 3T cells with their practical impact on module processes and performance as well as the effect of varying voltage ratios on the string-end losses. If the subcells are connected in series, the module integration requires insulation layers and significantly longer interconnects compared to devices with reverse-connected subcells. Tandem devices with a reverse connection and a voltage ratio between top and bottom cell of 2:1 allow a lean interconnection design and low integration losses. We present an approach for the integration of bypass diodes for the protection against shading effects that allow to minimize string-end and shading losses for a system of modules featuring 3T cells.
14.
D Eggert; M Yasin; R Puknat
Effizienzbewertung der Wärmeversorgung von Mehrfamilienhäusern im Bestand Vortrag
11.11.2022, (14. EffizienzTagung klimaneutral Bauen+Modernisieren).
@misc{Eggert2022c,
title = {Effizienzbewertung der Wärmeversorgung von Mehrfamilienhäusern im Bestand},
author = {D Eggert and M Yasin and R Puknat},
year = {2022},
date = {2022-11-11},
note = {14. EffizienzTagung klimaneutral Bauen+Modernisieren},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
15.
B Epp; P Pärisch
PVT-Wärmepumpensysteme: Doppelt Sonne für vierfachen Ertrag Vortrag
Hannover, Germany, 11.11.2022, (14. EffizienzTagung klimaneutral Bauen+Modernisieren).
@misc{Epp2022b,
title = {PVT-Wärmepumpensysteme: Doppelt Sonne für vierfachen Ertrag},
author = {B Epp and P Pärisch},
year = {2022},
date = {2022-11-11},
address = {Hannover, Germany},
note = {14. EffizienzTagung klimaneutral Bauen+Modernisieren},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
16.
B Schiebler; J Jensen; F Giovannetti
Kostengünstige & zuverlässige Solarthermieanlagen: Eine Lösung zur schnellen Reduktion fossiler Heizenergie, Ergebnisse aus dem F&E-Projekt HP-SYS Vortrag
Petershagen, Germany, 10.11.2022, (12. Projektleitungstreffen ENERGIEWENDEBAUEN).
@misc{Schiebler2022e,
title = {Kostengünstige & zuverlässige Solarthermieanlagen: Eine Lösung zur schnellen Reduktion fossiler Heizenergie, Ergebnisse aus dem F&E-Projekt HP-SYS},
author = {B Schiebler and J Jensen and F Giovannetti},
year = {2022},
date = {2022-11-10},
address = {Petershagen, Germany},
note = {12. Projektleitungstreffen ENERGIEWENDEBAUEN},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
17.
R Puknat; M Yasin; D Eggert
Automatisierte Effizienzbewertung der Wärmeversorgung von Mehrfamilienhäusern Vortrag
Petershagen, Germany, 09.11.2022, (12. Projektleitungstreffen ENERGIEWENDEBAUEN).
@misc{Puknat2022c,
title = {Automatisierte Effizienzbewertung der Wärmeversorgung von Mehrfamilienhäusern},
author = {R Puknat and M Yasin and D Eggert},
year = {2022},
date = {2022-11-09},
address = {Petershagen, Germany},
note = {12. Projektleitungstreffen ENERGIEWENDEBAUEN},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
18.
J Schmidt
Wie gewinnt man Strom aus der Sonne? Vortrag
Hannover, Germany, 05.11.2022, (AnsprechBAR: Tag der offenen Tür der Leibniz Universität).
@misc{Schmidt2022c,
title = {Wie gewinnt man Strom aus der Sonne?},
author = {J Schmidt},
year = {2022},
date = {2022-11-05},
address = {Hannover, Germany},
note = {AnsprechBAR: Tag der offenen Tür der Leibniz Universität},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
19.
C Xu; B Min; R Reineke-Koch
In: AIP Advances, Bd. 12, Nr. 11, S. 115007, 2022.
@article{Xu2022,
title = {Extended Tauc--Lorentz model (XTL) with log-normal distributed bandgap energies for optical permittivity in polycrystalline semiconductors},
author = {C Xu and B Min and R Reineke-Koch},
doi = {10.1063/5.0119256},
year = {2022},
date = {2022-11-01},
urldate = {2022-11-01},
journal = {AIP Advances},
volume = {12},
number = {11},
pages = {115007},
publisher = {American Institute of Physics},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
20.
F Haase; C Hollemann; N Wehmeier; K Bothe; B Min; H Schulte-Huxel; R Brendel; R Peibst
In: Solar RRL, Bd. 6, Ausg. 11, S. 2200583, 2022.
@article{Haase2022,
title = {Design of Large Poly-Si on Oxide Interdigitated Back Contact Silicon Solar Cells with Local Al–p+ Contacts in the Constraints of Measurement and Module Integration},
author = {F Haase and C Hollemann and N Wehmeier and K Bothe and B Min and H Schulte-Huxel and R Brendel and R Peibst},
doi = {10.1002/solr.202200583},
year = {2022},
date = {2022-11-01},
urldate = {2022-09-15},
journal = {Solar RRL},
volume = {6},
issue = {11},
pages = {2200583},
abstract = {Interdigitated back contact (IBC) silicon solar cells with a passivating n-type poly-Si on oxide emitter and an aluminum-doped p+ base contact on M2-sized Ga-doped p-type Cz wafers are reported. The Al-doped base contact forms during the firing of the printed contacts and allows for a lean process flow. The device optimization balances recombination at the base contacts against resistive losses and respects constraints set by the need of interconnecting cells in a module and contacting the cells temporally by a measurement chuck. A special sample holder is designed for measuring the Isc–Voc curve of the IBC cell with a busbar-less metal grid. The pseudo-efficiency is 24.7%. All fingers of each polarity are connected with wires and an efficiency of 22.3% is measured. The comparison of simulations and measurements reveals that the cell has 23.4% efficiency without the series resistance losses due to the wires. A huge part of the resistive losses in the cell are the transport losses of the majorities in the base dissipating a power that corresponds to 0.76%abs efficiency and the resistive losses at the Al-doped base contact (0.29%abs).},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Interdigitated back contact (IBC) silicon solar cells with a passivating n-type poly-Si on oxide emitter and an aluminum-doped p+ base contact on M2-sized Ga-doped p-type Cz wafers are reported. The Al-doped base contact forms during the firing of the printed contacts and allows for a lean process flow. The device optimization balances recombination at the base contacts against resistive losses and respects constraints set by the need of interconnecting cells in a module and contacting the cells temporally by a measurement chuck. A special sample holder is designed for measuring the Isc–Voc curve of the IBC cell with a busbar-less metal grid. The pseudo-efficiency is 24.7%. All fingers of each polarity are connected with wires and an efficiency of 22.3% is measured. The comparison of simulations and measurements reveals that the cell has 23.4% efficiency without the series resistance losses due to the wires. A huge part of the resistive losses in the cell are the transport losses of the majorities in the base dissipating a power that corresponds to 0.76%abs efficiency and the resistive losses at the Al-doped base contact (0.29%abs).