@article{Witteck2016b,
title = {Optimized interconnection of passivated emitter and rear cells by experimentally verified modeling},
author = {R Witteck and D Hinken and M R Vogt and J Müller and S Blankemeyer and H Schulte-Huxel and M Köntges and K Bothe and R Brendel},
doi = {10.1109/JPHOTOV.2016.2514706},
year = {2016},
date = {2016-03-01},
journal = {IEEE Journal of Photovoltaics},
volume = {6},
number = {2},
pages = {432-439},
abstract = {Recent reports about new cell efficiency records are highlighting the continuing development of passivated emitter and rear cells (PERC). Additionally, volume production has started, forming the basis for cutting edge solar modules. However, transferring the high efficiency of the cells into a module requires an adaptation of the conventional front metallization and of the cell interconnection design. This paper studies and compares the module output of various cell interconnection technologies, including conventional cell interconnection ribbons and wires. We fabricate solar cells and characterize their electrical and optical properties. From the cells, we build experimental modules with various cell interconnection technologies. We determine the optical and electrical characteristics of the experimental modules. Based on our experimental results, we develop an analytical model that reproduces the power output of the experimental modules within the measurement uncertainty. The analytical model is then applied to simulate various cell interconnection technologies employing halved cells, optical enhanced cell interconnectors, and multiwires. We also consider the effect of enhancing the cell-to-cell spacing. Based on the experimentally verified simulations, we propose an optimized cell interconnection for a 60-PERC module that achieves a power output of 323 W. Our simulations reveal that wires combined with halved cells show the best module performance. However, applying light-harvesting structures to the cell interconnection ribbons is an attractive alternative for upgrading existing production lines.},
keywords = {cell interconnection, Conductivity, Optical device fabrication, Optical variables measurement, passivated emitter and rear cells (PERC), Photovoltaic cells, Resistance, Silicon solar cell, solar module, Thyristors, Wires},
pubstate = {published},
tppubtype = {article}
}

@article{Schäfer2016,
title = {Light trapping and surface passivation of micron-scaled macroporous blind holes},
author = {S Schäfer and C Gemmel and S Kajari-Schröder and R Brendel},
doi = {10.1109/JPHOTOV.2015.2505179},
year = {2016},
date = {2016-03-01},
journal = {IEEE Journal of Photovoltaics},
volume = {6},
number = {2},
pages = {397-403},
abstract = {We fabricate a blind hole surface texture by anodic etching of macroporous Si. The blind holes, i.e., pores that do not penetrate the wafer completely, have an average diameter of 2.7 μm, a distance of 4 μm, and a depth of 9 μm. This texture is capable of reducing the AM1.5G photon flux-weighted front reflectance to 1.5% without depositing an antireflection coating. The μm-feature size makes it a less fragile alternative to common nm-sized black silicon structures. We passivate the blind holes by atomic layer deposited AlOx. The blind hole texture allows for a carrier lifetime of (2.2 ± 0.25) ms corresponding to an effective surface recombination velocity of (8 ± 1.5) cm/s with respect to the macroscopic front surface. A direct comparison of the optical performance and the surface passivation quality with a standard SiNx-coated random pyramid surface shows that blind holes allow for a relative efficiency gain of (3 ± 0.2)% when applied, e.g., in an otherwise perfect back-contacted solar cell.},
keywords = {Absorption, charge carrier lifetime, Current density, Etching, Optical losses, optical reflectivity, Optical variables measurement, silicon, Surface texture},
pubstate = {published},
tppubtype = {article}
}