@article{Schulte-Huxel2018b,
title = {String-Level Modeling of Two, Three, and Four Terminal Si-Based Tandem Modules},
author = {H Schulte-Huxel and D J Friedman and A C Tamboli},
doi = {10.1109/JPHOTOV.2018.2855104},
year = {2018},
date = {2018-09-01},
journal = {IEEE Journal of Photovoltaics},
volume = {8},
number = {5},
pages = {1370-1375},
abstract = {III-V/Si tandem solar cells have demonstrated efficiencies exceeding the theoretical efficiency limit of silicon solar cells. On the cell level, device modeling shows that three-terminal tandem (3T) devices with rear contacted bottom Si cells perform as well as operating the subcells independently (4T). However, integrating these 3T devices in a module requires voltage matching of the top and the bottom cell. Here, we investigate the robustness of parallel/series-interconnected 3T III-V/Si tandem devices in comparison with series-interconnected two terminal (2T) and independently operated (4T) devices with respect to spectral, thermal, and resistive effects. Under most conditions, interconnected 3T devices are able to perform as well as those with independent operation of the top and bottom cell, and 3T devices significantly outperform 2T devices.},
keywords = {module interconnection, Multijunction solar cells, Silicon solar cell, tandem device},
pubstate = {published},
tppubtype = {article}
}

@article{SCHULTEHUXEL2016743,
title = {Impact of Ag Pads on the Series Resistance of PERC Solar Cells},
author = {H Schulte-Huxel and R Witteck and P van Laak and T Brendemühl and D Hinken and K Bothe and R Brendel},
doi = {10.1016/j.egypro.2016.07.053},
issn = {1876-6102},
year = {2016},
date = {2016-08-01},
journal = {Energy Procedia},
volume = {92},
pages = {743-749},
abstract = {Screen-printed passivated emitter and rear cells (PERC) require Ag pads on the rear side to enable solderable connections for module integration. These Ag pads are separated from the silicon by a dielectric layer to avoid recombination of minority charge carriers. The drawback of this configuration is an elongated transport path for the majority charge carriers generated above the pads. This results in an increase in series resistance. The strength of this effect depends on charge carrier generation above the Ag pads that critically depends on shading of the cell's front side. Ag pads are usually wider than the busbars or the interconnector ribbons and thus are only partially shaded. We build PERC test structures with various rear side configurations of Ag and Al screen printing as well as with and without laser contact openings (LCO). Using experiments and finite element simulations we investigate the impact of shading the Ag pads by the busbars and other means. While fully shaded regions do not increase the lumped solar cell's series resistance, unshaded Ag pads lead to an increase of about 37%.},
note = {Proceedings of the 6th International Conference on Crystalline Silicon Photovoltaics (SiliconPV 2016)},
keywords = {laser fiered contacts, laser welding, module interconnection, PERC solar cells},
pubstate = {published},
tppubtype = {article}
}

@article{Schulte-Huxel2016c,
title = {Simultaneous Contacting and Interconnection of Passivated Emitter and Rear Solar Cells},
author = {H Schulte-Huxel and J -H Petermann and S Blankemeyer and V Steckenreiter and S Kajari-Schröder and R Brendel},
doi = {10.1016/j.egypro.2016.07.135},
issn = {1876-6102},
year = {2016},
date = {2016-08-01},
journal = {Energy Procedia},
volume = {92},
pages = {515-522},
abstract = {The back end process of passivated emitter and rear cells (PERC) consists of at least one laser process and three screen-printing steps followed by the stringing and tabbing of the cells. To reduce the number of steps we have developed a process that metallizes the rear side including contact formation and simultaneously interconnects the cells. We attach an Al foil to an encapsulant layer. By laser processing we form ‘laser-fired and bonding contacts’ (LFBC) on the passivated rear side of the solar cells. The Al foil contacting the rear is laser welded to the Ag screen-printed front side metallization of the next cell and thus forms the cell interconnection. The laser contacts on the rear show a surface recombination velocity Scont for the contact regions of cm/s and a contact resistivity of 3.52 mΩcm2. We present a first proof-of concept module combining the in-laminate Ag-Al laser welding and the LFBC reaching an efficiency of 18.4%. In accelerated aging test modules show no degradation (< 1% in efficiency) after 100 humidity-free cycles.},
note = {Proceedings of the 6th International Conference on Crystalline Silicon Photovoltaics (SiliconPV 2016)},
keywords = {laser fiered contacts, laser welding, module interconnection, PERC solar cells},
pubstate = {published},
tppubtype = {article}
}

@article{Schulte-Huxel2015c,
title = {Interconnection of busbar-free back contacted solar cells by laser welding},
author = {H Schulte-Huxel and S Blankemeyer and A Merkle and V Steckenreiter and S Kajari-Schröder and R Brendel},
doi = {10.1002/pip.2514},
year = {2015},
date = {2015-08-01},
journal = {Progress in Photovoltaics: Research and Applications},
volume = {23},
number = {8},
pages = {1057-1065},
keywords = {Al metallization, back-junction back-contact solar cell, laser welding, module interconnection, multilevel metallization, photovoltaic module, silver-free},
pubstate = {published},
tppubtype = {article}
}

@inproceedings{Petermann2013,
title = {Module interconnection of both sides-contacted silicon solar cells by screen-printing},
author = {J H Petermann and H Schulte-Huxel and V Steckenreiter and R Gogolin and S Eidelloth and T Dullweber and S Kajari-Schröder and R Brendel},
editor = {IEEE},
doi = {10.1109/PVSC.2013.6745190},
isbn = {978-1-4799-3299-3},
year = {2013},
date = {2013-06-16},
booktitle = {2013 IEEE 39th Photovoltaic Specialists Conference (PVSC) },
journal = {Proceedings of the 39th IEEE Photovoltaic Specialists Conference},
pages = {3448-3453},
address = {Tampa, FL, USA},
keywords = {Glass, heterojunction, Hybrid silicon, Integrated circuit interconnections, Lasers, module interconnection, module level processing, passivation, Photovoltaic cells, Resistance, screen-printing, silicon},
pubstate = {published},
tppubtype = {inproceedings}
}