Publications by Mathieu Gérard Boccard

Synergetic substrate and additive engineering for over 30%-efficient perovskite-Si tandem solar cells

Christophe Ballif, Mounir Driss Mensi, Quentin Thomas Jeangros, Mathieu Gérard Boccard, Daniel Anthony Jacobs, Kerem Artuk, Xin Yu Chin, Deniz Türkay, Christian Michael Wolff

Perovskite-silicon (Si) tandem solar cells are the most prominent contenders to succeed single-junction Si cells that dominate the market today. Yet, to justify the added cost of inserting a perovskite cell on top of Si, these devices should first exhibit ...

2024

Loss Analysis of a 24.4%-Efficient Front-Junction Silicon Heterojunction Solar Cell and Opportunity for Localized Contacts

Christophe Ballif, Mathieu Gérard Boccard, Jean Cattin, Luca Massimiliano Antognini, Vincent Philippe Paratte, Julie Amandine Dreon, Deniz Türkay

Silicon heterojunction (SHJ) solar cells have recently reached power conversion efficiencies above 25% with various device architectures and with industrial size (>200 cm(2)) wafers. Yet, for an accurate assessment of the efficiency potential and further d ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2023

Carrier-selective contacts using metal compounds for crystalline silicon solar cells

Mathieu Gérard Boccard, Julie Amandine Dreon

Solar cells rely on the efficient generation of electrons and holes and the subsequent collection of these photoexcited charge carriers at spatially separated electrodes. High wafer quality is now commonplace for crystalline silicon (c-Si) based solar cell ...

WILEY2023

Interface passivation for 31.25%-efficient perovskite/silicon tandem solar cells

Christophe Ballif, Mounir Driss Mensi, Quentin Thomas Jeangros, Mathieu Gérard Boccard, Peter Joseph Fiala, Quentin Jean-Marie Armand Guesnay, Daniel Anthony Jacobs, Kerem Artuk, Xin Yu Chin, Deniz Türkay, Christian Michael Wolff

Silicon solar cells are approaching their theoretical efficiency limit of 29%. This limitation can be exceeded with advanced device architectures, where two or more solar cells are stacked to improve the harvesting of solar energy. In this work, we devise ...

American Association for the Advancement of Science2023

Bandgap engineering of indium gallium nitride layers grown by plasma-enhanced chemical vapor deposition

Christophe Ballif, Aïcha Hessler-Wyser, Nicolas Würsch, Franz-Josef Haug, Mathieu Gérard Boccard, Jonathan Emanuel Thomet

This paper reports on the fabrication of In xGa 1 - xN (InGaN) layers with various compositions ranging from InN to GaN using a cost-effective low-temperature plasma-enhanced chemical vapor deposition (PECVD) method and analyzes the influence of deposition ...

2022

Monocrystalline 1.7-eV MgCdTe solar cells

Mathieu Gérard Boccard

Monocrystalline 1.7 eV Mg0.13Cd0.87Te/MgxCd1-xTe (x > 0.13) double heterostructure (DH) solar cells with varying Mg compositions in the barrier layers are grown by molecular beam epitaxy. A Mg0.13Cd0.87Te/Mg0.37Cd0.63Te DH solar cell featuring abrupt inter ...

AIP Publishing2022

Status and perspectives of crystalline silicon photovoltaics in research and industry

Christophe Ballif, Franz-Josef Haug, Mathieu Gérard Boccard

Crystalline silicon (c-Si) photovoltaics has long been considered energy intensive and costly. Over the past decades, spectacular improvements along the manufacturing chain have made c-Si a low-cost source of electricity that can no longer be ignored. Over ...

2022

Integration of thin n-type nc-Si:H layers in the window-multilayer stack of heterojunction solar cells

Christophe Ballif, Mathieu Gérard Boccard, Luca Massimiliano Antognini, Vincent Philippe Paratte, Laurie-Lou Senaud, Julie Amandine Dreon, Corentin Yann Sthioul

N-type nanocrystalline silicon (nc-Si:H(n)) layers are good candidates to improve current and transport properties in heterojunction solar cells. In this work, we perform thickness series alongside PH3 doping series to unravel the desirable characteristics ...

ELSEVIER2022

Contact Resistivity Measurements and their Applicability for Accurate Series Resistance Breakdown in Heterojunction Solar Cell

Christophe Ballif, Mathieu Gérard Boccard, Matthieu Despeisse, Luca Massimiliano Antognini, Laurie-Lou Senaud, Bertrand Yves Paul Paviet-Salomon, Lison Sylou Marthey, Julie Amandine Dreon, Deniz Türkay

In this work, we use several approaches to perform accurate Series Resistance (R-S) breakdown of a state of the art 2 cm x 2 cm screen-printed solar cell reaching 82.5% FF. On the one hand, Haschke et al.'s model for the lateral transport through the cell, ...

AMER INST PHYSICS2022

New metric for carrier selective contacts for silicon heterojunction solar cells

Mathieu Gérard Boccard, Jakub Holovsky

Heterojunction carrier selective contacts for solar cells have gained great attention because of the ability of these contacts to efficiently collect majority carriers while hindering the recombination of minority carriers, thus resulting in the highest re ...

PERGAMON-ELSEVIER SCIENCE LTD2022

Bottom-Up and Top-Down Approaches for Identifying and Mitigating Electrical Losses in Silicon Heterojunction Solar Cells

Christophe Ballif, Mathieu Gérard Boccard, Luca Massimiliano Antognini

Electrical losses in silicon heterojunction (SHJ) solar cells are difficult to identify and to control as multiple material layers and several entangled physical phenomena are involved. In this context, this contribution aims to accurately investigate and ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2022

Influence of the Dopant Gas Precursor in P-Type Nanocrystalline Silicon Layers on the Performance of Front Junction Heterojunction Solar Cells

Christophe Ballif, Quentin Thomas Jeangros, Mathieu Gérard Boccard, Jean Cattin, Luca Massimiliano Antognini, Mario Joe Lehmann, Vincent Philippe Paratte, Laurie-Lou Senaud, Jan Haschke, Julie Amandine Dreon

Silicon heterojunction solar cells can employ p-type hydrogenated nanocrystalline silicon nc-Si:H(p) on their front side, since these can provide better transparency and contact resistance compared to hydrogenated p-type amorphous silicon layers. We invest ...

2021

ZnSnxGe1-xN2 as electron-selective contact for silicon heterojunction solar cells

Christophe Ballif, Mathieu Gérard Boccard, Jonathan Emanuel Thomet, Luca Massimiliano Antognini, Vincent Philippe Paratte, Julie Amandine Dreon, Julien Hurni, Davi Marcelo Fébba

This work reports the electrical characterization of ZnSnxGe1-xN2 (ZTGN) layers deposited on glass by sputtering and further assesses for the first time the performance of SHJ solar cells featuring them as electron-selective contacts. Bandgap, conductivity ...

IEEE2021

Advanced method for electrical characterization of carrier-selective passivating contacts using transfer-length-method measurements under variable illumination

Christophe Ballif, Antoine Descoeudres, Nicolas Badel, Sylvain Nicolay, Gabriel Christmann, Mathieu Gérard Boccard, Matthieu Despeisse, Jonas Geissbühler, Laurie-Lou Senaud, Bertrand Yves Paul Paviet-Salomon

2021

Effects of work function and electron affinity on the performance of carrier-selective contacts in silicon solar cells using $ZnSn_{x}Ge_{1-x}N_{2}$ as a case study

Christophe Ballif, Mathieu Gérard Boccard, Jonathan Emanuel Thomet, Luca Massimiliano Antognini, Vincent Philippe Paratte, Julie Amandine Dreon, Julien Hurni, Davi Marcelo Fébba

2021

Temperature‐dependent performance of silicon heterojunction solar cells with transition‐metal‐oxide‐based selective contacts

Mathieu Gérard Boccard, Julie Amandine Dreon

The temperature coefficient (TC) is an essential figure of merit to accurately evaluate solar cell performance at various operating temperatures and hence enabling the comparison between different cell technologies. Recently, solar cells that use passivati ...

2021

Influence of Light Soaking on Silicon Heterojunction Solar Cells With Various Architectures

Christophe Ballif, Mathieu Gérard Boccard, Matthieu Despeisse, Jean Cattin, Laurie-Lou Senaud, Bertrand Yves Paul Paviet-Salomon, Jan Haschke

In this article, we investigate the effect of prolonged light exposure on silicon heterojunction solar cells. We show that, although light exposure systematically improves solar cell efficiency in the case of devices using intrinsic and p-type layers with ...

2021

Palliating the efficiency loss due to shunting in perovskite/silicon tandem solar cells through modifying the resistive properties of the recombination junction

Christophe Ballif, Sylvain Nicolay, Gabriel Christmann, Mathieu Gérard Boccard

As the efficiency of commercial crystalline silicon solar cells approaches its maximum theoretical value, tandem architectures are becoming increasingly popular to continue the push to higher photovoltaic performances. Thin-film materials are particularly ...

2021

Dopant-Free Bifacial Silicon Solar Cells

Christophe Ballif, Mathieu Gérard Boccard, Jean Cattin, Luca Massimiliano Antognini, Vincent Philippe Paratte, Julie Amandine Dreon, Sihua Zhong, Wenjie Lin, Hui Shen

Herein, challenges in the fabrication of full dopant-free bifacial silicon solar cells are discussed and efficient devices utilizing a MoO3/ indium tin oxide (ITO)/Ag hole-selective contact and ZnO/LiFx/Al electron-selective contacts with up to 79% short-c ...

2021

Effects of Work Function and Electron Affinity on the Performance of Carrier-Selective Contacts in Silicon Solar Cells Using ZnSnx Ge-1 (-) N-x(2) as a Case Study

Christophe Ballif, Mathieu Gérard Boccard, Jonathan Emanuel Thomet, Luca Massimiliano Antognini, Vincent Philippe Paratte, Julie Amandine Dreon, Julien Hurni

This work reports the electrical characterization of ZnSnx Ge1 - xN2 (ZTGN) layers (10% < x < 90%) deposited on glass by combinatorial sputtering and further assesses the performance of silicon heterojunction (SHJ) solar cells featuring them as electron-se ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2021