Publications by Loris Barraud | EPFL Graph Search

Rear-emitter silicon heterojunction solar cells with atomic layer deposited ZnO:Al serving as an alternative transparent conducting oxide to In2O3:Sn

Christophe Ballif, Antoine Descoeudres, Nicolas Badel, Sylvain Nicolay, Gabriel Christmann, Matthieu Despeisse, Loris Barraud

Here high-efficiency (above 21%) large-area silicon heterojunction solar cells with atomic layer deposited ZnO:Al as front- or back-side transparent conducting oxide are demonstrated. Photoconductance decay measurements indicate that the excellent chemical ...

2019

Highly Conductive and Broadband Transparent Zr-Doped In2O3 as Front Electrode for Solar Cells (vol 8, pg 1202, 2018)

Christophe Ballif, Mathieu Gérard Boccard, Matthieu Despeisse, Loris Barraud, Raphaël Monnard, Jakub Holovsky, Monica Morales Masis, Oscar Esteban Rucavado Leandro

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2019

Silicon Heterojunction Solar Cells on Quasi-mono Wafers

Christophe Ballif, Antoine Descoeudres, Mathieu Gérard Boccard, Matthieu Despeisse, Loris Barraud, Raphaël Monnard, Jan Haschke, Brahim Aissa

We applied hydrogen passivation, gettering and a combination of both to quasi-mono (qm) wafer material to enhance its bulk lifetime and prepared silicon heterojunction (SHJ) solar cells. We find that while our applied hydrogen passivation alone seems not t ...

IEEE2018

Fully textured monolithic perovskite/silicon tandem solar cells with 25.2% power conversion efficiency

Christophe Ballif, Laura Ding, Sylvain Nicolay, Quentin Thomas Jeangros, Davide Sacchetto, Mathieu Gérard Boccard, Matthieu Despeisse, Jérémie Werner, Florent Sahli, Loris Barraud, Raphaël Monnard, Gianluca Cattaneo, Bertrand Yves Paul Paviet-Salomon, Björn Niesen, Matthias Wolfgang Bräuninger

Tandem devices combining perovskite and silicon solar cells are promising candidates to achieve power conversion efficiencies above 30% at reasonable costs. State-of-the-art monolithic two-terminal perovskite/silicon tandem devices have so far featured sil ...

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

Interdigitated back contact silicon heterojunction solar cells featuring an interband tunnel junction enabling simplified processing

Christophe Ballif, Antoine Descoeudres, Nicolas Badel, Benjamin Strahm, Antonin Faes, Sylvain Nicolay, Quentin Thomas Jeangros, Gabriel Christmann, Stefaan De Wolf, Matthieu Despeisse, Loris Barraud, Jonas Geissbühler, Johannes Peter Seif, Andrea Tomasi, Bertrand Yves Paul Paviet-Salomon

This paper reports on the development of an innovative back-contacted crystalline silicon solar cell with passivating contacts featuring an interband tunnel junction at its electron-collecting contacts. In this novel architecture, named "tunnel-IBC", both ...

2018

Highly Conductive and Broadband Transparent Zr-Doped In2O3 as Front Electrode for Solar Cells

Christophe Ballif, Mathieu Gérard Boccard, Matthieu Despeisse, Loris Barraud, Raphaël Monnard, Jakub Holovsky, Monica Morales Masis, Oscar Esteban Rucavado Leandro

2018

Improved Optics in Monolithic Perovskite/Silicon Tandem Solar Cells with a Nanocrystalline Silicon Recombination Junction

Christophe Ballif, Aïcha Hessler-Wyser, Sylvain Nicolay, Quentin Thomas Jeangros, Stefaan De Wolf, Matthieu Despeisse, Jérémie Werner, Florent Sahli, Loris Barraud, Raphaël Monnard, Johannes Peter Seif, Andrea Tomasi, Bertrand Yves Paul Paviet-Salomon, Björn Niesen, Matthias Wolfgang Bräuninger

Perovskite/silicon tandem solar cells are increasingly recognized as promi-sing candidates for next-generation photovoltaics with performance beyond the single-junction limit at potentially low production costs. Current designs for monolithic tandems rely ...

2017

Raising the one-sun conversion efficiency of III-V/Si solar cells to 32.8% for two junctions and 35.9% for three junctions

Christophe Ballif, Antoine Descoeudres, Matthieu Despeisse, Loris Barraud, Stephanie Essig

Today's dominant photovoltaic technologies rely on single-junction devices, which are approaching their practical efficiency limit of 25-27%. Therefore, researchers are increasingly turning to multi-junction devices, which consist of two or more stacked su ...

Nature Publishing Group2017

ITO/MoOx/a-Si:H(i) Hole-Selective Contacts for Silicon Heterojunction Solar Cells: Degradation Mechanisms and Cell Integration

Christophe Ballif, Aïcha Hessler-Wyser, Antoine Descoeudres, Sylvain Nicolay, Quentin Thomas Jeangros, Gabriel Christmann, Davide Sacchetto, Matthieu Despeisse, Loris Barraud, Jonas Geissbühler

Molybdenum oxide is an efficient hole collector for silicon solar cells. However, its optoelectronic properties deteriorate during cell manufacturing. To assess this issue, the optoelectronic properties and microstructure of molybdenum oxide-based hole con ...

2017

Simple processing of back-contacted silicon heterojunction solar cells using selective-area crystalline growth

Christophe Ballif, Antoine Descoeudres, Sylvain Nicolay, Quentin Thomas Jeangros, Gabriel Christmann, Stefaan De Wolf, Matthieu Despeisse, Loris Barraud, Johannes Peter Seif, Andrea Tomasi, Bertrand Yves Paul Paviet-Salomon, Jan Haschke

For crystalline-silicon solar cells, voltages close to the theoretical limit are nowadays readily achievable when using passivating contacts. Conversely, maximal current generation requires the integration of the electron and hole contacts at the back of t ...

Nature Publishing Group2017

Asymmetric band offsets in silicon heterojunction solar cells: Impact on device performance

Christophe Ballif, Antoine Descoeudres, Stefaan De Wolf, Loris Barraud, Johannes Peter Seif, Ugur Deneb Menda

Amorphous/crystalline silicon interfaces feature considerably larger valence than conduction band offsets. In this article, we analyze the impact of such band offset asymmetry on the performance of silicon heterojunction solar cells. To this end, we use si ...

Amer Inst Physics2016

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

Realization of GaInP/Si Dual-Junction Solar Cells With 29.8% 1-Sun Efficiency

Christophe Ballif, Antoine Descoeudres, Nicolas Badel, Antonin Faes, Jacques Levrat, Matthieu Despeisse, Loris Barraud, Bertrand Yves Paul Paviet-Salomon, Stephanie Essig

Combining a Si solar cell with a high-bandgap top cell reduces the thermalization losses in the short wavelength and enables theoretical 1-sun efficiencies far over 30%. We have investigated the fabrication and optimization of Si-based tandem solar cells w ...

Ieee-Inst Electrical Electronics Engineers Inc2016

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

Back-Contacted Silicon Heterojunction Solar Cells: Optical-Loss Analysis and Mitigation

Christophe Ballif, Antoine Descoeudres, Sylvain Nicolay, Stefaan De Wolf, Matthieu Despeisse, Loris Barraud, Andrea Tomasi, Bertrand Yves Paul Paviet-Salomon

We analyze the optical losses that occur in interdigitated back-contacted amorphous/crystalline silicon heterojunction solar cells. We show that in our devices, the main loss mechanisms are similar to those of two-side contacted heterojunction solar cells. ...

Ieee-Inst Electrical Electronics Engineers Inc2015

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

Silicon Heterojunction Solar Cells With Copper-Plated Grid Electrodes: Status and Comparison With Silver Thick-Film Techniques

Christophe Ballif, Antoine Descoeudres, Nicolas Badel, Antonin Faes, Quentin Thomas Jeangros, Stefaan De Wolf, Matthieu Despeisse, Loris Barraud, Jonas Geissbühler, Andrea Tomasi

Copper electroplating is investigated and compared with common silver printing techniques for the front metallization of silicon heterojunction solar cells. We achieve smaller feature sizes by electroplating, significantly reducing optical shadowing losses ...

Ieee-Inst Electrical Electronics Engineers Inc2014

Hydrogen-doped indium oxide/indium tin oxide bilayers for high-efficiency silicon heterojunction solar cells

Christophe Ballif, Antoine Descoeudres, Nicolas Badel, Stefaan De Wolf, Corsin Battaglia, Loris Barraud

The front transparent conductive oxide layer is a source of significant optical and electrical losses in silicon heterojunction solar cells because of the trade-off between free-carrier absorption and sheet resistance. We demonstrate that hydrogen-doped in ...

Elsevier2013

Amorphous/crystalline silicon interface defects induced by hydrogen plasma treatments

Christophe Ballif, Bénédicte Demaurex, Duncan Thomas Lindsay Alexander, Stefaan De Wolf, Loris Barraud, Jonas Geissbühler, Johannes Peter Seif

Excellent amorphous/crystalline silicon interface passivation is of extreme importance for high-efficiency silicon heterojunction solar cells. This can be obtained by inserting hydrogen-plasma treatments during deposition of the amorphous silicon passivati ...

American Institute of Physics2013