Publications de Andrea Tomasi | EPFL Graph Search

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

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

The impact of silicon solar cell architecture and cell interconnection on energy yield in hot & sunny climates

Christophe Ballif, Jacques Levrat, Stefaan De Wolf, Matthieu Despeisse, Jean Cattin, Yannick Samuel Riesen, Johannes Peter Seif, Andrea Tomasi, Jan Haschke, Brahim Aissa

Extensive knowledge of the dependence of solar cell and module performance on temperature and irradiance is essential for their optimal application in the field. Here we study such dependencies in the most common high-efficiency silicon solar cell architec ...

Royal Soc Chemistry2017

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

Impact of organic overlayers on a-Si:H/c-Si surface potential

Christophe Ballif, Stefaan De Wolf, Johannes Peter Seif, Andrea Tomasi, Björn Niesen

Bilayers of intrinsic and doped hydrogenated amorphous silicon, deposited on crystalline silicon (c-Si) surfaces, simultaneously provide contact passivation and carrier collection in silicon heterojunction solar cells. Recently, we have shown that the pres ...

American Institute of Physics2017

Profilometry of thin films on rough substrates by Raman spectroscopy

Christophe Ballif, Stefaan De Wolf, Matthieu Despeisse, Jonas Geissbühler, Andrea Tomasi, Bertrand Yves Paul Paviet-Salomon, Martin Ledinsky

Thin, light-absorbing films attenuate the Raman signal of underlying substrates. In this article, we exploit this phenomenon to develop a contactless thickness profiling method for thin films deposited on rough substrates. We demonstrate this technique by ...

Nature Research2016

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

Back-Contacted Silicon Heterojunction Solar Cells

Andrea Tomasi

Wood/timber has been widely used for house and bridge construction. It is a widely available natural material that necessitates low energy for the production, following simple processes. The environmentally friendliness, together with the low cost of raw m ...

EPFL2016

Nanocrystalline Silicon Carrier Collectors for Silicon Heterojunction Solar Cells and Impact on Low-Temperature Device Characteristics

Christophe Ballif, Quentin Thomas Jeangros, Stefaan De Wolf, Nicolas Würsch, Franz-Josef Haug, Yannick Samuel Riesen, Johannes Peter Seif, Andrea Tomasi, Gizem Nogay

Silicon heterojunction solar cells typically use stacks of hydrogenated intrinsic/doped amorphous silicon layers as carrier selective contacts. However, the use of these layers may cause parasitic optical absorption losses and moderate fill factor (FF) val ...

Ieee-Inst Electrical Electronics Engineers Inc2016

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

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

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

Back-Contacted Silicon Heterojunction Solar Cells With Efficiency >21%

Christophe Ballif, Antoine Descoeudres, Stefaan De Wolf, Jonas Geissbühler, Andrea Tomasi, Bertrand Yves Paul Paviet-Salomon, Silvia Martin de Nicolas Agut

We report on the fabrication of back-contacted silicon heterojunction solar cells with conversion efficiencies above 21%. Our process technology relies solely on simple and size-scalable patterning methods, with no high-temperature steps. Using in situ sha ...

Ieee-Inst Electrical Electronics Engineers Inc2014