Publications by Arnaud Walter | EPFL Graph Search

Rear textured p-type high temperature passivating contacts and their implementation in perovskite/silicon tandem cells

Christophe Ballif, Antoine Descoeudres, Sylvain Nicolay, Quentin Thomas Jeangros, Philippe Wyss, Soo-Jin Moon, Arnaud Walter, Andrea Ingenito

Silicon solar cells based on high temperature passivating contacts are becoming mainstream in the photovoltaic industry. Here, we developed a high-quality boron-doped poly-silicon hole contact. When combined with a co-processed phosphorus-doped poly-silico ...

Royal Soc Chemistry2023

Instability of p-i-n perovskite solar cells under reverse bias

Christophe Ballif, Laura Ding, Sylvain Nicolay, Quentin Thomas Jeangros, Arnaud Walter, Florent Sahli, Peter Joseph Fiala, Chien-Jen Yang, Fan Fu, Marion Solange Madeleine Dussouillez, Ricardo Augusto Zanotto Razera, Daniel Anthony Jacobs

Partial shading can trigger permanent damage in photovoltaic modules because the illuminated solar cells drive the shaded cells into reverse bias. Under reverse bias conditions, perovskite solar cells have been shown to degrade quickly due to processes tha ...

Royal Society of Chemistry2020

Low-Temperature Screen-Printed Metallization for the Scale-Up of Two-Terminal Perovskite-Silicon Tandems

Christophe Ballif, Nicolas Badel, Antonin Faes, Jacques Levrat, Laura Ding, Sylvain Nicolay, Gabriel Christmann, Soo-Jin Moon, Arnaud Walter, Adriana Paracchino, Matthieu Despeisse, Bertrand Yves Paul Paviet-Salomon

Tandem photovoltaic devices based on perovskite and crystalline silicon (PK/c-Si) absorbers have the potential to push commercial silicon single junction devices beyond their current efficiency limit. However, their scale-up to industrially relevant sizes ...

AMER CHEMICAL SOC2019

Perovskite/Perovskite/Silicon Monolithic Triple-Junction Solar Cells with a Fully Textured Design

Christophe Ballif, Sylvain Nicolay, Quentin Thomas Jeangros, Arnaud Walter, Jérémie Werner, Florent Sahli, Björn Niesen, Fan Fu

High efficiency triple-junction solar cells are currently made of III−V semiconductors using expensive deposition methods. Perovskite/perovskite/silicon monolithic triple-junction solar cells could be a lower-cost alternative as no epitaxial growth is requ ...

2018

Complex Refractive Indices of Cesium–Formamidinium-Based Mixed-Halide Perovskites with Optical Band Gaps from 1.5 to 1.8 eV

Christophe Ballif, Sylvain Nicolay, Quentin Thomas Jeangros, Gabriel Christmann, Arnaud Walter, Jérémie Werner, Florent Sahli, Björn Niesen, Gizem Nogay, Philipp Friedrich Hermann Löper, Matthias Wolfgang Bräuninger, Peter Joseph Fiala, Chien-Jen Yang

Cesium-formamidinium-based mixed-halide perovskite materials with optical band gaps ranging from 1.5 to 1.8 eV are investigated by variable-angle spectroscopic ellipsometry. The determined complex refractive indices are shown to depend on the fabrication p ...

2018

Hybrid sequential deposition process for fully textured perovskite/silicon tandem solar cells

Christophe Ballif, Laura Ding, Sylvain Nicolay, Quentin Thomas Jeangros, Soo-Jin Moon, Arnaud Walter, Davide Sacchetto, Mathieu Gérard Boccard, Matthieu Despeisse, Jérémie Werner, Florent Sahli, Loris Barraud, Raphaël Monnard, Monica Morales Masis, Gianluca Cattaneo, Bertrand Yves Paul Paviet-Salomon, Björn Niesen, Gizem Nogay, Oscar Esteban Rucavado Leandro, Matthias Wolfgang Bräuninger, Peter Joseph Fiala, Chien-Jen Yang, Fan Fu

Tandem solar cells that feature a high-bandgap perovskite cell on top of a lower bandgap silicon cell have the potential to reach efficiencies > 30%. Here, we present a versatile hybrid deposition method that yields conformal perovskite cells directly on t ...

IEEE2018

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

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

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

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

The Role of Transport Agents in MoS2 Single Crystals

Helmuth Berger, László Forró, Arnaud Magrez, Bálint Náfrádi, Arnaud Walter, Jacim Jacimovic, Andrea Pisoni

We report resistivity, thermoelectric power, and thermal conductivity of MoS2 single crystals prepared by the chemical vapor transport (CVT) method using I-2, Br-2, and TeCl4 as transport agents. The material presents low-lying donor and acceptor levels, w ...

Amer Chemical Soc2015

Laser-Scribing Patterning for the Production of Organometallic Halide Perovskite Solar Modules

Christophe Ballif, Laurent Fabien Hubert Sansonnens, Sylvain Nicolay, Jun Ho Yum, Soo-Jin Moon, Arnaud Walter, Mustapha Benkhaira, Julien Claude Bailat

Efficiencies of solar cells based on organometallic halide perovskite absorber material have dramatically increased over the past few years. Most of efficiencies reported so far have, however, been obtained on solar cells with very small lab-scale area of ...

Ieee-Inst Electrical Electronics Engineers Inc2015

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

Functionalized graphene grown by oxidative dehydrogenation chemistry

László Forró, Daniel Oberli, Arnaud Magrez, Arnaud Walter, Jacim Jacimovic, Massimo Spina, Endre Horvath, Laurent Syavoch Bernard

We report on a highly efficient growth of graphene using dehydrogenation of acetylene by an oxidative reaction with carbon dioxide. In few seconds, large-area of copper foil used as catalyst of the reaction is fully covered with graphene. The yield of the ...

Pergamon-Elsevier Science Ltd2014