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Björn Niesen

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Related publications (44)

Imaging the Spatial Evolution of Degradation in Perovskite/Si Tandem Solar Cells After Exposure to Humid Air

Christophe Ballif, Stefaan De Wolf, Jérémie Werner, Florent Sahli, Björn Niesen, Randall Ellingson

Monolithically integrated two-terminal perovskite/Si tandem solar cells promise to achieve high power conversion efficiency. However, there is a concern that the stability of the perovskite top cell will limit the long-term performance of tandem devices. T ...

Ieee-Inst Electrical Electronics Engineers Inc2017

Tuning the Optoelectronic Properties of ZnO:Al by Addition of Silica for Light Trapping in High-Efficiency Crystalline Si Solar Cells

Christophe Ballif, Aïcha Hessler-Wyser, Ali Dabirian, Stefaan De Wolf, Monica Morales Masis, Björn Niesen

Highly transparent electrodes with a well-tuned refractive index are essential for a wide range of optoelectronic devices, such as light emitting diodes and solar cells. Here, it is shown that the transparency of ZnO:Al can be improved and its refractive i ...

Wiley-Blackwell2016

Progression towards high efficiency perovskite solar cells via optimisation of the front electrode and blocking layer

Christophe Ballif, Sylvain Nicolay, Soo-Jin Moon, Arnaud Walter, Davide Sacchetto, Björn Niesen, Matthias Wolfgang Bräuninger

The effects of a fluorine doped tin oxide (FTO) electrode, titanium dioxide (TiO2-x) blocking layer (BL) and perovskite (methyl ammonium lead triiodide) preparation on the overall properties of the photovoltaic cells have been studied. The FTO electrode wa ...

Royal Society of Chemistry2016

Transparent Electrodes in Silicon Heterojunction Solar Cells: Influence on Contact Passivation

Christophe Ballif, Sylvain Nicolay, Stefaan De Wolf, Florent Sahli, Loris Barraud, Johannes Peter Seif, Lorenzo Fanni, Andrea Tomasi, Bertrand Yves Paul Paviet-Salomon, Björn Niesen, Silvia Martin de Nicolas Agut

Charge carrier collection in silicon heterojunction solar cells occurs via intrinsic/doped hydrogenated amorphous silicon layer stacks deposited on the crystalline silicon wafer surfaces. Usually, both the electron and hole collecting stacks are externally ...

Ieee-Inst Electrical Electronics Engineers Inc2016

Parasitic Absorption Reduction in Metal Oxide-Based Transparent Electrodes: Application in Perovskite Solar Cells

Christophe Ballif, Sylvain Nicolay, Ali Dabirian, Stefaan De Wolf, Jérémie Werner, Monica Morales Masis, Björn Niesen

Transition metal oxides (TMOs) are commonly used in a wide spectrum of device applications, thanks to their interesting electronic, photochromic, and electrochromic properties. Their environmental sensitivity, exploited for gas and chemical sensors, is how ...

Amer Chemical Soc2016

Efficient Monolithic Perovskite/Silicon Tandem Solar Cell with Cell Area >1 cm

Christophe Ballif, Arnaud Walter, Stefaan De Wolf, Luc Fesquet, Jérémie Werner, Johannes Peter Seif, Björn Niesen, Ching-Hsun Weng

Monolithic perovskite/crystalline silicon tandem solar cells hold great promise for further performance improvement of well-established silicon photovoltaics; however, monolithic tandem integration is challenging, evidenced by the modest performances and s ...

Amer Chemical Soc2016

Efficient Near-Infrared-Transparent Perovskite Solar Cells Enabling Direct Comparison of 4-Terminal and Monolithic Perovskite/Silicon Tandem Cells

Christophe Ballif, Sylvain Nicolay, Soo-Jin Moon, Arnaud Walter, Davide Sacchetto, Nicolas Tétreault, Stefaan De Wolf, Matthieu Despeisse, Jérémie Werner, Florent Sahli, Loris Barraud, Bertrand Yves Paul Paviet-Salomon, Björn Niesen, Matthias Wolfgang Bräuninger

Combining market-proven silicon solar cell technology with an efficient wide band gap top cell into a tandem device is an attractive approach to reduce the cost of photovoltaic systems. For this, perovskite solar cells are promising high-efficiency top cel ...

Amer Chemical Soc2016

In Situ TEM Analysis of Organic-Inorganic Metal-Halide Perovskite Solar Cells under Electrical Bias

Christophe Ballif, Aïcha Hessler-Wyser, Quentin Thomas Jeangros, Martial Duchamp, Jérémie Werner, Björn Niesen

Changes in the nanostructure of methylammonium lead iodide (MAPbI(3)) perovskite solar cells are assessed as a function of current-voltage stimulus by biasing thin samples in situ in a transmission electron microscope. Various degradation pathways are iden ...

American Chemical Society2016

Zinc tin oxide as high-temperature stable recombination layer for mesoscopic perovskite/silicon monolithic tandem solar cells

Christophe Ballif, Sylvain Nicolay, Soo-Jin Moon, Arnaud Walter, Davide Sacchetto, Stefaan De Wolf, Xavier Niquille, Jérémie Werner, Monica Morales Masis, Björn Niesen, Philipp Friedrich Hermann Löper, Oscar Esteban Rucavado Leandro

Perovskite/crystalline silicon tandem solar cells have the potential to reach efficiencies beyond those of silicon single-junction record devices. However, the high-temperature process of 500 °C needed for state-of-the-art mesoscopic perovskite cells has, ...

American Institute of Physics2016

Probing Photocurrent Nonuniformities in the Subcells of Monolithic Perovskite/Silicon Tandem Solar Cells

Christophe Ballif, Stefaan De Wolf, Jérémie Werner, Florent Sahli, Björn Niesen, Randall Ellingson

Perovskite/silicon tandem solar cells with high power conversion efficiencies have the potential to become a commercially viable photovoltaic option in the near future. However, device design and optimization is challenging because conventional characteriz ...

Amer Chemical Soc2016

Cyanine tandem and triple-junction solar cells

Frank Nüesch, Hui Zhang, Björn Niesen, Roland Hany, Lei Wang, René Uwe Schneider

Ultrathin bilayer heterojunction solar cells using cyanine electron donors and electron acceptor C-60 are used to fabricate monolithically stacked tandem and triple junction devices. Sub-cell stack sequences as well as C-60 layer thicknesses are optimized ...

Elsevier2016

Amorphous silicon-germanium for triple and quadruple junction thin-film silicon based solar cells

Christophe Ballif, Grégory Bugnon, Franz-Josef Haug, Mathieu Gérard Boccard, Matthieu Despeisse, Michael Elias Stückelberger, Maximilien Joseph Marie Bonnet-Eymard, Björn Niesen

We study amorphous silicon-germanium (a-SiGe:H) as intrinsic absorber material for thin-film silicon-based triple and quadruple junction solar cells. First, we present the development of a-SiGe:H single junction devices, in particular the Ge-content gradin ...

Elsevier2015

Solar Hydrogen Production by Amorphous Silicon Photocathodes Coated with a Magnetron Sputter Deposited Mo

Christophe Ballif, Xile Hu, Laurent Liardet, Carlos Gilberto Morales Guio, Björn Niesen

Coupling of Earth-abundant hydrogen evolution catalysts to photoabsorbers is crucial for the production of hydrogen fuel using sunlight. In this work, we demonstrate the use of magnetron sputtering to deposit Mo2C as an efficient hydrogen evolution reactio ...

Amer Chemical Soc2015

Organic-inorganic halide perovskite/crystalline silicon four-terminal tandem solar cells

Christophe Ballif, Sylvain Nicolay, Jun Ho Yum, Soo-Jin Moon, Stefaan De Wolf, Julien Claude Bailat, Björn Niesen, Martin Ledinsky

Tandem solar cells constructed from a crystalline silicon (c-Si) bottom cell and a low-cost top cell offer a promising way to ensure long-term price reductions of photovoltaic modules. We present a four-terminal tandem solar cell consisting of a methyl amm ...

Royal Society of Chemistry2015

Complex Refractive Index Spectra of CH3NH3PbI3 Perovskite Thin Films Determined by Spectroscopic Ellipsometry and Spectrophotometry

Christophe Ballif, Jun Ho Yum, Soo-Jin Moon, Stefaan De Wolf, Michael Elias Stückelberger, Jérémie Werner, Björn Niesen

The complex refractive index (dielectric function) of planar CH3NH3PbI3 thin films at room temperature is investigated by variable angle spectroscopic ellipsometry and spectrophotometry. Knowledge of the complex refractive index is essential for designing ...

Amer Chemical Soc2015

22.5% efficient silicon heterojunction solar cell with molybdenum oxide hole collector

Christophe Ballif, Aïcha Hessler-Wyser, Sylvain Nicolay, Stefaan De Wolf, Matthieu Despeisse, Jérémie Werner, Loris Barraud, Andrea Tomasi, Björn Niesen

Substituting the doped amorphous silicon films at the front of silicon heterojunction solar cells with wide-bandgap transition metal oxides can mitigate parasitic light absorption losses. This was recently proven by replacing p-type amorphous silicon with ...

American Institute of Physics2015

Raman Spectroscopy of Organic-Inorganic Halide Perovskites

Christophe Ballif, Jun Ho Yum, Soo-Jin Moon, Stefaan De Wolf, Jakub Holovsky, Björn Niesen, Martin Ledinsky

Micro-Raman spectroscopy provides laterally resolved microstructural information for a broad range of materials. In this Letter, we apply this technique to tri-iodide (CH3NH3PbI3), tribromide (CH3NH3PbBr3), and mixed iodide-bromide (CH3NH3PbI3-xBrx) organi ...

Amer Chemical Soc2015

CH3NH3PbI3 perovskite/silicon tandem solar cells: characterization based optical simulations

Christophe Ballif, Stefaan De Wolf, Björn Niesen

In this study we analyze and discuss the optical properties of various tandem architectures: mechanically stacked (four-terminal) and monolithically integrated (two-terminal) tandem devices, consisting of a methyl ammonium lead triiodide (CH3NH3PbI3) perov ...

Optical Society of America2015

Tuning the porosity of zinc oxide electrodes: from dense to nanopillar films

Christophe Ballif, Sylvain Nicolay, Lorenzo Fanni, Monica Morales Masis, Benoît Florent Paul Delaup, Björn Niesen

Thin films with tunable porosity are of high interest in applications such as gas sensing and antireflective coatings. We report a facile and scalable method to fabricate ZnO electrodes with tuneable porosity. By adjusting the substrate temperature and rat ...

2015

Sputtered rear electrode with broadband transparency for perovskite solar cells

Christophe Ballif, Guy Joseph Günter Dubuis, Sylvain Nicolay, Soo-Jin Moon, Arnaud Walter, Stefaan De Wolf, Jérémie Werner, Monica Morales Masis, Björn Niesen, Philipp Friedrich Hermann Löper

Due to their high efficiencies combined with simple and cost-effective device fabrication, perovskite solar cells are promising candidates as top cells in tandem devices. For this application, the perovskite solar cell must be highly transparent at near-in ...

Elsevier2015

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