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Christophe Ballif

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Publications associées (427)

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Understanding of photocurrent enhancement in real thin film solar cells: towards optimal onedimensional gratings

Christophe Ballif, Hans Peter Herzig, Toralf Scharf, Vincent Paeder, Ali Naqavi, Karin Söderström

Despite the progress in the engineering of structures to enhance photocurrent in thin film solar cells, there are few comprehensive studies which provide general and intuitive insight into the problem of light trapping. Also, lack of theoretical propositio ...

Optical Society of America2011

A New View of Microcrystalline Silicon: The Role of Plasma Processing in Achieving a Dense and Stable Absorber Material for Photovoltaic Applications

Christophe Ballif, Matthieu Despeisse, Jakub Holovsky, Grégory Bugnon, Peter Cuony, Gaetano Parascandolo, Simon Hänni

To further lower production costs and increase conversion efficiency of thin-film silicon solar modules, challenges are the deposition of high-quality microcrystalline silicon (μc-Si:H) at an increased rate and on textured substrates that guarantee efficie ...

2012

Facile preparation of micron- and nano-scale textured master for nano-imprinting front electrode in thin-film silicon tandem cells with improved light trapping

Christophe Ballif, Franz-Josef Haug, Etienne Antoine Julien Moulin

This paper reports a facile method to prepare a textured surface with combined micron- and nano-scale surface features, which is used as master for nano-imprinting process to obtain transparent front electrodes in thin-film silicon tandem cells. The micron ...

Elsevier2015

Reinforcement Learning for Joint Design and Control of Battery-PV Systems

Christophe Ballif, Nicolas Würsch, Laure-Emmanuelle Perret Aebi, Marine Dominique Cauz

The decentralisation and unpredictability of new renewable energy sources require rethinking our energy system. Data-driven approaches, such as reinforcement learning (RL), have emerged as new control strategies for operating these systems, but they have n ...

2023

Wire-sawing processes: parametrical study and modeling

Christophe Ballif, Mathijs Pieter van der Meer

Reducing the wafer breakage rate without changing the wafer thickness and sawing thinner wafers while maintaining constant breakage rate are two possibilities to decrease the costs of solar cells. They are similar in the sense that both require stronger wa ...

Elsevier2015

From PV to EV: Mapping the Potential for Electric Vehicle Charging with Solar Energy in Europe

Christophe Ballif, Nicolas Würsch, Alejandro Pena Bello, Noémie Alice Yvonne Ségolène Jeannin, Jérémy Dumoulin

The electrification of the transport sector is a key element in decarbonizing our societies. However, energy systems will have to cope with additional electricity demand due to the charging needs of electric vehicles (EVs) together with the integration of ...

2024

FINAL RESULTS OF THE EUROPEAN PROJECT FLEXCELLENCE ROLL TO ROLL TECHNOLOGY FOR THE PRODUCTION OF HIGH EFFICIENCY LOW COST THIN FILM SOLAR CELLS

Christophe Ballif, Franz-Josef Haug, Vanessa Terrazzoni-Daudrix

This paper reports on the final main results of the Flexcellence project. The project was running for 3 years and its goal was the development of equipments and processes for cost-effective roll-to-roll production of high-efficiency flexible thin-film sili ...

2009

TEM characterization of textured silicon heterojunction solar cells

Christophe Ballif, Aïcha Hessler-Wyser, Christian Monachon

Increasing the efficiency of crystalline silicon (c-Si) solar cells requires the reduction of both bulk and interface recombination. Even if bulk recombination is almost suppressed, the symmetry of the crystal lattice is disturbed at the surface and hence, ...

Springer2008

In-Situ Monitoring of Moisture Ingress in PV Modules Using Digital Humidity Sensors

Christophe Ballif, Laure-Emmanuelle Perret Aebi, Hengyu Li, Eleonora Annigoni, Fanny Sculati-Meillaud

A new in-situ moisture monitoring technique for photovoltaic (PV) modules is proposed using miniature digital humidity and temperature sensors. The sensors were embedded in three different ethylene-vinyl-acetate (EVA) stacks and proved to be resistant to l ...

Ieee-Inst Electrical Electronics Engineers Inc2016

Light trapping in solar cells: can periodic beat random?

Christophe Ballif, Franz-Josef Haug, Matthieu Despeisse, Mathieu Gérard Boccard, Marco Cantoni, Duncan Thomas Lindsay Alexander, Corsin Battaglia, Jordi Escarre Palou, Karin Söderström

Theory predicts that periodic photonic nanostructures should outperform their random counterparts in trapping light in solar cells. However, the current certified world-record conversion efficiency for amorphous silicon thin-film solar cells, which strongl ...

2012

Distributed flexibility as a cost-effective alternative to grid reinforcement

Christophe Ballif, Nicolas Würsch, Jordan Holweger, Alejandro Pena Bello, Noémie Alice Yvonne Ségolène Jeannin

The deployment of distributed photovoltaics (PV) in low-voltage networks may cause technical issues such as voltage rises, line ampacity violations, and transformer overloading for distribution system operators (DSOs). These problems may induce grid reinfo ...

ELSEVIER2023

The effect of partial shading on the reliability of photovoltaic modules in the built-environment

Christophe Ballif, Alessandro Francesco Aldo Virtuani, Ebrar Özkalay

Residential photovoltaic systems often experience partial shading from chimneys, trees or other structures, which can induce hot-spots in the modules. If the temperature and frequency of these hot-spots are high, the module's reliability and safety may be ...

Edp Sciences S A2024

Impact of the Oxygen Flow during the Magnetron Sputtering Deposition on the Indium Tin Oxide thin films for Silicon Heterojunction Solar Cell

Christophe Ballif, Mathieu Gérard Boccard, Jan Haschke, Jean Cattin, Akshath Raghu Shetty

We report on the optoelectronic properties of ITO layers deposited by DC sputtering, using different oxygen to total flow ratios [r(O-2) = O-2/Ar, ranging from 1% to 8%], for silicon heterojunction (SHJ) solar cell application. The depth profiling of the v ...

IEEE2019

Bulk Defects and Hydrogenation Kinetics in Crystalline Silicon Solar Cells With Fired Passivating Contacts

Christophe Ballif, Franz-Josef Haug, Andrea Ingenito, Mario Joe Lehmann, Philippe Wyss, Audrey Marie Isabelle Morisset

In this article, the effect of the various processing steps during the fabrication of c-Si/SiOx/SiCx fired passivating contacts on the silicon bulk lifetime is studied, and the kinetics of defect deactivation by hydrogenation is investigated. It is found t ...

2022

Mechanical integrity of hybrid indium-free electrodes for flexible devices

Christophe Ballif, Yves Leterrier, Monica Morales Masis, Ali Dabirian, Fabien Paul Jacques Dauzou

Maintaining electrical conductivity, optical transparency, and mechanical integrity against bending and stretching are key requirements for flexible transparent electrodes. Transparent conducting oxides (TCOs) are widely used thin film electrodes in optoel ...

Elsevier2016

The effect of storage conditions on the long-term stability of ethylene-vinyl-acetate (EVA) copolymer used in glass/glass modules

Christophe Ballif, Alessandro Francesco Aldo Virtuani, Eleonora Annigoni, Andrew Wayne Fairbrother, Luca Gnocchi

We evaluate the effect of storage conditions of uncured encapsulant rolls and the potential consequences on photovoltaic (PV) module performance. We show the impact of residual water trapped inside laminated double glass PV modules after lamination and dur ...

ELSEVIER2023

Light-induced Voc increase and decrease in high-efficiency amorphous silicon solar cells

Christophe Ballif, Franz-Josef Haug, Matthieu Despeisse, Michael Elias Stückelberger, Yannick Samuel Riesen, Jan-Willem Alexander Schüttauf

High-efficiency amorphous silicon (a-Si:H) solar cells were deposited with different thicknesses of the p-type amorphous silicon carbide layer on substrates of varying roughness. We observed a light-induced open-circuit voltage (Voc) increase upon light so ...

American Institute of Physics2014

Organometallic Halide Perovskites: Sharp Optical Absorption Edge and Its Relation to Photovoltaic Performance

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

Solar cells based on organometallic halide perovskite absorber layers are emerging as a high-performance photovoltaic technology. Using highly sensitive photothermal deflection and photocurrent spectroscopy, we measure the absorption spectrum of CH3NH3PbI3 ...

Amer Chemical Soc2014

Integrated thinking for photovoltaics in buildings

Christophe Ballif, Emmanuel Rey, Sophie Lufkin, Laure-Emmanuelle Perret Aebi

Recent developments in photovoltaic technologies enable stimulating architectural integration into building façades and rooftops. Upcoming policies and a better coordination of all stakeholders will transform how we approach building-integrated photovoltai ...

2018

Optical Evaluation of the Rear Contacts of Crystalline Silicon Solar Cells by Coupled Electromagnetic and Statistical Ray-Optics Modeling

Christophe Ballif, Franz-Josef Haug, Stefaan De Wolf, Monica Morales Masis, Ali Dabirian

High-efficiency crystalline silicon (c-Si) solar cells increasingly feature sophisticated electron and hole contacts aimed at minimizing electronic losses. At the rear of photovoltaic devices, such contacts-usually consisting of stacks of functional layers ...

Ieee-Inst Electrical Electronics Engineers Inc2017