71 research outputs found
Cross-contamination in single-chamber processes for thin-film silicon solar cells
No full textWoerdenweber J, Merdzhanova T, Zimmermann T, et al. Cross-contamination in single-chamber processes for thin-film silicon solar cells. Journal of Non-Crystalline Solids. 2012;358(17):2183-2186
Single-chamber processes for a-Si:H solar cell deposition
No full textMerdzhanova T, Woerdenweber J, Zimmermann T, et al. Single-chamber processes for a-Si:H solar cell deposition. Solar Energy Materials and Solar Cells. 2011;98:146-153
Critical oxygen concentration in hydrogenated amorphous silicon solar cells dependent on the contamination source
No full textWoerdenweber J, Merdzhanova T, Stiebig H, Beyer W, Gordijn A. Critical oxygen concentration in hydrogenated amorphous silicon solar cells dependent on the contamination source. Appl. Phys. Lett. Submitted;96(10): 103505
Incorporation and critical concentration of oxygen in a-Si:H solar cells
No full textWoerdenweber J, Merdzhanova T, Gordijn A, Stiebig H, Beyer W. Incorporation and critical concentration of oxygen in a-Si:H solar cells. Solar Energy Materials and Solar Cells. 2011;95(10):2811-2815
High critical oxygen concentration in microcrystalline silicon solar cells
No full textMerdzhanova T, Woerdenweber J, Beyer W, Zastrow U, Stiebig H, Gordijn A. High critical oxygen concentration in microcrystalline silicon solar cells. Physica Status Solidi - Rapid Res. Lett. 2010;4(11):323-325
Impurities in thin-film silicon: Influence on material properties and solar cell performance
No full textMerdzhanova T, Woerdenweber J, Beyer W, et al. Impurities in thin-film silicon: influence on material properties and solar cell performance. Journal of Non-Crystalline Solids. 2012;358(17):2171-2178
Influence of base pressure and atmospheric contaminants on a-Si:H solar cell properties
No full textWoerdenweber J, Merdzhanova T, Schmitz R, et al. Influence of base pressure and atmospheric contaminants on a-Si:H solar cell properties. Journal of Applied Physics. 2008;104(9): 94507
SiGe wet chemical etchants with high compositional selectivity and low strain sensitivity
No full textBattery storage to keep the artificial leaf running during the night : Implications and impact of direct battery coupling to solar electrolysers
No full textSolar based hydrogen power is promising as a renewable fuel that can be generated anywhere there is sunshine and water. Many attempts have been made to integrate a water electrolyser and solar cell into one seamless package (a so-called artificial leaf) to take advantage of the cooling provided by the water to the solar cell, reduced losses from the lack of wiring and the increased portability afforded by an integrated unit 1. However, in literature, much less attention is payed to the need for a minimum current across the electrolyser under insufficient illumination to prevent excessive catalyst degradation and dissolution2. Attaching an appropriately sized, voltage matched battery to an artificial leaf could address this need and in theory could also increase efficiency of the setup across one diurnal cycle. We experimentally show that this can be achieved without any power electronics and, as is theorized, the presence of the battery also has a positive effect on the operation of the electrolyser and improves solar-to-hydrogen efficiency by reducing the current density across the electrolyser. A 7 cell silicon heterojunction module , two bifunctional NiFeMo electrolysers in series and a commercial Li-ion NMC battery were selected to provide the same amount of solar output power despite different working voltages and tested in a series of simulated diurnal cycles. The increased average solar to hydrogen efficiency per cycle (11.4% vs 10.5% without the battery) is analyzed and discussed with implications for future integrated artificial leaf design and implementation. 1. M. Lee, B. Turan, J.-P. Becker, K. Welter, B. Klingebiel, E. Neumann, Y. J. Sohn, T. Merdzhanova, T. Kirchartz, F. Finger, U. Rau and S. Haas, Advanced Sustainable Systems, 2020, 4, 2000070. 2. A. Weiß, A. Siebel, M. Bernt, T. H. Shen, V. Tileli and H. A. Gasteiger, Journal of The Electrochemical Society, 2019, 166, F487-F497
Modeling of photoluminescence spectra and quasi-Fermi level splitting in μc-Si:H solar cells
No full textWe developed a model describing the photoluminescence spectra from hydrogenated microcrystalline silicon (μc-Si:H). From the model we derived analytical relations between the separation of the quasi-Fermi levels and PL-peak energy and intensity. These relations may be useful when photoluminescence or electroluminescence based methods are applied for characterization of μc-Si:H solar cells and modules. We compared the model with experimental PL spectra from a μc-Si:H solar cell. Our model can consistently explain the relation between the measured PL-peak intensity, energy and the measured open circuit voltage of the μc-Si:H solar cell
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