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Christophe Ballif

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Publications associées (443)

Compressive-shear adhesion characterization of polyvinyl-butyral and ethylene-vinyl acetate at different curing times before and after exposure to damp-heat conditions

Christophe Ballif, Valentin Chapuis, Hengyu Li, Laure-Emmanuelle Perret Aebi

Photovoltaic (PV) module efficiency and reliability are two factors that have an important impact on the final cost of the PV electricity production. It is widely accepted that a good adhesion between the encapsulant and the different substrates of a PV mo ...

Wiley-Blackwell2012

Light trapping in solar cells: can periodic beat random?

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

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

Time evolution of surface defect states in hydrogenated amorphous silicon studied by photothermal and photocurrent spectroscopy and optical simulation

Christophe Ballif, Matthieu Despeisse, Michael Elias Stückelberger, Jakub Holovsky

The time evolution of surface defect density and width of space charge region in thin layer of amorphous silicon is observed experimentally by Fourier transform photocurrent spectroscopy. This work reviews the assumption that photocurrent is insensitive to ...

Elsevier Science Bv2012

UV imprinting for thin film solar cell application

Christophe Ballif, Céline Pahud, Franz-Josef Haug, Corsin Battaglia, Jordi Escarre Palou, Rémi Biron

UV imprinting is an interesting, low cost technique to produce large area thin film solar cells incorporating nanometric textures. Here, we review and present new results confirming that replicas of the most common textures used in photovoltaics can be obt ...

2012

Insights into the encapsulation process of photovoltaic modules: GC-MS analysis on the curing step of Poly (ethylene-co-vinyl acetate) (EVA) encapsulant

Christophe Ballif, Yun Luo, Hengyu Li, Laure-Emmanuelle Perret Aebi

Appropriate encapsulation schemes are essential in protecting the active components of the photovoltaic (PV) module against weathering and to ensure long term reliability. For crystalline cells, Poly (ethylene-co-vinyl acetate) (EVA) is the most commonly u ...

Ismithers2012

Highly transparent ZnO bilayers by LP-MOCVD as front electrodes for thin-film micromorph silicon solar cells

Christophe Ballif, Laura Ding, Sylvain Nicolay, Grégory Bugnon, Mathieu Gérard Boccard, Matthieu Despeisse, Mustapha Benkhaira

ZnO bilayer films were deposited by a low-pressure metalorganic chemical vapor deposition technique in a single process step, by doping with boron only the nucleation stage of the growth. The resulting 2 pm thick layers are characterized by low free carrie ...

Elsevier2012

Improvement of the open circuit voltage by modifying the transparent ITO front electrode in amorphous n-i-p solar cells

Christophe Ballif, Jonathan Besuchet, Gilles Kratzer, Frank Jonathan Leresche, Franz-Josef Haug, Rémi Biron

At the front contact of thin film silicon solar cells, the junction between the p-doped window layer and the n-type transparent electrode results in a barrier that must be surmounted by the charge carriers. The barrier height is governed by the work functi ...

Wiley-Blackwell2012

Kinetics of a-Si:H bulk defect and a-Si:H/c-Si interface-state reduction

Christophe Ballif, Stefaan De Wolf

Low-temperature annealing of hydrogenated amorphous silicon (a-Si:H) is investigated. An identical energy barrier is found for the reduction of deep defects in the bulk of a-Si:H films and at the interface such layers form with crystalline Si (c-Si) surfac ...

2012

Geometric light trapping for high efficiency thin film silicon solar cells

Christophe Ballif, Laura Ding, Sylvain Nicolay, Grégory Bugnon, Franz-Josef Haug, Matthieu Despeisse, Corsin Battaglia, Jordi Escarre Palou

The imprinting of random square based pyramidal textures with micrometric scale at the air/glass interface of thin film silicon solar cells is presented as an efficient alternative to anti-reflective coatings to minimize reflection losses at the cell entra ...

Elsevier2012

Diffraction and absorption enhancement from textured back reflectors of thin film solar cells

Christophe Ballif, Franz-Josef Haug, Ali Naqavi

We study light scattering and absorption in thin film solar cells, using a model system of a sinusoidally textured silver reflector and dielectric layers of ZnO and amorphous silicon. Experimental results are compared to a theoretical model based on a Rayl ...

American Institute of Physics2012

Stencil-nanopatterned back reflectors for thin-film amorphous silicon n-i-p solar cells

Christophe Ballif, Céline Pahud, Jürgen Brugger, Oscar Vazquez Mena, Andreea Veronica Savu, Mona Julia Katharina Klein, Franz-Josef Haug

We fabricated amorphous silicon n-i-p solar cells with two types of nanopatterned back reflectors using stencil lithography. One reflector type has a plasmonic grating that is embedded in the ZnO layer; the other one has a metallic grating patterned on top ...

Ieee2012

Multiple-junction photoelectric device and its production process

Christophe Ballif, Peter Cuony, Gaetano Parascandolo, Matthieu Despeisse

The present invention relates to a multiple-junction photoelectric device comprising, in sequence, a substrate (4), a first conducting layer (2), at least two elementary photoelectric devices (6, 10), at least one of said elementary photoelectric devices ( ...

2012

High-Efficiency Amorphous Silicon Solar Cell on a Periodic Nanocone Back Reflector

Christophe Ballif, Céline Pahud, Franz-Josef Haug, Corsin Battaglia

An amorphous silicon solar cell on a periodic nanocone back reflector with a high 9.7% initial conversion efficiency is presented. The optimized back-reflector morphology provides powerful light trapping and enables excellent electrical cell performance. U ...

2012

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

Christophe Ballif, Thomas Söderström, Peter Cuony, Gaetano Parascandolo, Grégory Bugnon, Matthieu Despeisse, Jakub Holovsky, 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

New challenges in solar architectural innovation

Christophe Ballif, Yves Leterrier, Christian Roecker, Jean-Louis Scartezzini, Andreas Schueler, Valentin Chapuis, Krista Susan Lumsden Friedli

Among the century’s main challenges, climate change and the need for energy sources diversification are of great importance. In this context, renewable energies undoubtedly have an important role to play. Photovoltaic (PV) electricity is especially well su ...

EPFL2011

LPCVD ZnO-based intermediate reflector for micromorph tandem solar cells

Christophe Ballif, Thomas Söderström, Laura Ding, Sylvain Nicolay, Grégory Bugnon, Matthieu Despeisse

The use of zinc oxide (ZnO) based intermediate reflector (ZIR) in micromorph solar cells using low pressure chemical vapor deposition (LPCVD) was investigated. The influences of deposition temperature and dopant gas concentration on grain size and lateral ...

2011

New Challenges in Solar Architectural Innovation

Christophe Ballif, Yves Leterrier, Christian Roecker, Andreas Schueler, Vanessa Terrazzoni-Daudrix

2011

High fidelity transfer of nanometric random textures by UV embossing for thin film solar cells applications

Christophe Ballif, Karin Söderström, Franz-Josef Haug, Corsin Battaglia, Jordi Escarre Palou

We investigate the transfer of random nanostructures commonly used in thin film silicon solar cells onto inexpensive substrates, such as glass or flexible polyethylene sheets. Morphological and optical analyses of masters and replicas show the successful t ...

Elsevier2011

Window layer with p doped silicon oxide for high V-oc thin-film silicon n-i-p solar cells

Christophe Ballif, Céline Pahud, Franz-Josef Haug, Jordi Escarre Palou, Rémi Biron

We investigate the influence of the oxygen content in boron-doped nanocrystalline silicon oxide films (p-nc-SiOx) and introduce this material as window layer in n-i-p solar cells. The dependence of both, optical and electrical properties on the oxygen cont ...

American Institute of Physics2011

Solar cell and its production process

Christophe Ballif, Franz-Josef Haug

The present invention relates to a solar cell comprising a support (6), a back electrode layer (5), at least a hydrogenated microcrystalline silicon photoelectric device (9), and a top electrode layer (11). The back electrode layer (5) has a rough surface. ...

2011

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