R Brendel
In: Solar RRL, Bd. 7, Ausg. 17, S. 2300279, 2023.
@article{Brendel2023,
title = {Analytic Efficiency Optimization of Solar Cells under Light Concentration in the Framework of the Single-Diode Model},
author = {R Brendel},
doi = {10.1002/solr.202300279},
year = {2023},
date = {2023-09-01},
urldate = {2023-09-01},
journal = {Solar RRL},
volume = {7},
issue = {17},
pages = {2300279},
abstract = {Herein, concentrating solar cells are modeled with two recombination active contacts and a recombination active light absorber in the framework of the one-diode model. The two contacts and the absorber contribute to a lumped series resistance and to a lumped recombination current. It is proven that varying the light concentration can be interpreted as iso-selectivity scaling of the cell's resistance and the cell's recombination. As a consequence of that, the optimal efficiency of a concentrator cell is found at maximum combined selectivity of the two contacts and the absorber. Herein, analytic formulas are derived that calculate the optimal contact areas and the optimal light concentration level for achieving an optimum efficiency. The resulting formulas express the efficiency in terms of the selectivities of each contact and the selectivity of the absorber. These equations are used to calculate the optimum contact area fractions and the optimum light concentration level for Si solar cells of various material qualities with screen-printed Al-doped contacts and n-type poly-Si contacts on oxide. The efficiency results of the novel analytic and a conventional numeric optimization agree to the expected level of accuracy.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
M Rienäcker
Measuring Selectivity and Extraction Efficiency: the Three-Terminal Suns-VOC Method Applied to an n-c-Si/SiOy/TiOx/Al Junction Vortrag
Online Event, 20.04.2021, (SiliconPV 2021 - 11th International Conference on Silicon Photovoltaics).
@misc{Rienäcker2021,
title = {Measuring Selectivity and Extraction Efficiency: the Three-Terminal Suns-VOC Method Applied to an n-c-Si/SiOy/TiOx/Al Junction},
author = {M Rienäcker},
year = {2021},
date = {2021-04-20},
address = {Online Event},
note = {SiliconPV 2021 - 11th International Conference on Silicon Photovoltaics},
keywords = {},
pubstate = {published},
tppubtype = {presentation}
}
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 Rienäcker; M Bossmeyer; A Merkle; U Römer; F Haase; J Krügener; R Brendel; R Peibst
In: IEEE Journal of Photovoltaics, Bd. 7, Nr. 1, S. 11-18, 2017, ISSN: 2156-3381.
@article{Rienäcker2017b,
title = {Junction resistivity of carrier-selective polysilicon on oxide junctions and its impact on solar cell performance},
author = {M Rienäcker and M Bossmeyer and A Merkle and U Römer and F Haase and J Krügener and R Brendel and R Peibst},
doi = {10.1109/JPHOTOV.2016.2614123},
issn = {2156-3381},
year = {2017},
date = {2017-01-01},
journal = {IEEE Journal of Photovoltaics},
volume = {7},
number = {1},
pages = {11-18},
abstract = {We investigate the junction resistivity of high-quality carrier-selective polysilicon on oxide (POLO) junctions with the transfer length method. We demonstrate n+ POLO junctions with a saturation current density JC,poly of 6.2 fA/cm2 and a junction resistivity ρc of 0.6 mΩcm2, counterdoped n+ POLO junctions with 2.7 fA/cm2 and 1.3 mΩcm2, and p+ POLO junctions with 6.7 fA/cm2 and 0.2 mΩcm2. Such low junction resistivities and saturation current densities correspond to excellent selectivities S10 of up to 16.2. The efficiency potential for back-junction back-contact solar cells with these POLO junctions was determined to be larger than 25 % by numerical device simulations. We demonstrate experimentally a back-junction back-contact solar cell with p-type and n-type POLO junctions with an independently confirmed efficiency of 24.25 %.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
R Brendel; M Rienaecker; R Peibst
A quantitative measure for the carrier selectivity of contacts to solar cells Proceedings Article
In: WIP, (Hrsg.): Proceedings of the 32nd European Photovoltaic Solar Energy Conference, S. 447-451, Munich, Germany, 2016, ISBN: 3-936338-41-8.
@inproceedings{Brendel2016,
title = {A quantitative measure for the carrier selectivity of contacts to solar cells},
author = {R Brendel and M Rienaecker and R Peibst},
editor = {WIP},
doi = {10.4229/EUPVSEC20162016-2CO.4.1},
isbn = {3-936338-41-8},
year = {2016},
date = {2016-09-01},
booktitle = {Proceedings of the 32nd European Photovoltaic Solar Energy Conference},
journal = {Proceedings of the 32nd European Photovoltaic Solar Energy Conference},
pages = {447-451},
address = {Munich, Germany},
abstract = {We discuss a physically motivated definition for a quantitative measure of the selectivity of electron and hole contacts. We define the selectivity S10 = log10(Vth /(c ×Jc)) to depend on the contact resistance c, the recombination current density Jc of the contact, and the thermal voltage Vth. A high selectivity relies on a highly asymmetric equilibrium carrier concentration of majority and minority carriers in the contact. The maximum efficiency max increases with the selectivity S10. This increase is linear until the efficiency starts to be limited by radiative recombination. We give analytic equations for calculating the maximum efficiency max(S10) of a crystalline Si cell that is ideal except for either one or two contacts. Achieving the maximum efficiency max requires optimized areal fractions fe,max and fh,max for the electron and the hole contacts, respectively . We give analytic equations for these contact fractions.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}