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Christophe Ballif

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Publications associées (443)

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

Amorphous silicon-germanium for triple and quadruple junction thin-film silicon based solar cells

Christophe Ballif, Grégory Bugnon, Franz-Josef Haug, Mathieu Gérard Boccard, Matthieu Despeisse, Michael Elias Stückelberger, Maximilien Joseph Marie Bonnet-Eymard, Björn Niesen

We study amorphous silicon-germanium (a-SiGe:H) as intrinsic absorber material for thin-film silicon-based triple and quadruple junction solar cells. First, we present the development of a-SiGe:H single junction devices, in particular the Ge-content gradin ...

Elsevier2015

Fast and non-destructive detection on the EVA gel content in photovoltaic modules by optical reflection

Christophe Ballif, Hengyu Li, Laure-Emmanuelle Perret Aebi

Poly(ethylene-co-vinyl acetate) (EVA) has been the dominating material in the photovoltaic (PV) encapsulant market for decades, owing to its superior cost-performance balance. To achieve its desired material properties, EVA undergoes a curing reaction duri ...

Ieee-Inst Electrical Electronics Engineers Inc2015

Raman Spectroscopy of Organic-Inorganic Halide Perovskites

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

Micro-Raman spectroscopy provides laterally resolved microstructural information for a broad range of materials. In this Letter, we apply this technique to tri-iodide (CH3NH3PbI3), tribromide (CH3NH3PbBr3), and mixed iodide-bromide (CH3NH3PbI3-xBrx) organi ...

Amer Chemical Soc2015

Effect of the thin-film limit on the measurable optical properties of graphene

Christophe Ballif, Sylvain Nicolay, Stefaan De Wolf, Jakub Holovsky

The fundamental sheet conductance of graphene can be directly related to the product of its absorption coefficient, thickness and refractive index. The same can be done for graphene's fundamental opacity if the so-called thin-film limit is considered. Here ...

Nature Publishing Group2015

Tuning the porosity of zinc oxide electrodes: from dense to nanopillar films

Christophe Ballif, Sylvain Nicolay, Lorenzo Fanni, Monica Morales Masis, Benoît Florent Paul Delaup, Björn Niesen

Thin films with tunable porosity are of high interest in applications such as gas sensing and antireflective coatings. We report a facile and scalable method to fabricate ZnO electrodes with tuneable porosity. By adjusting the substrate temperature and rat ...

2015

Effect of Cooling Press on the Optical Transmission through Photovoltaic Encapsulants

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

In certain laminators for poly (ethylene-co-vinyl acetate) (EVA) encapsulation process of photovoltaic modules, cooling press (CP) is applied to the module after encapsulation. Here, the effect of CP on the optical transmission through common PV encapsulan ...

Taylor & Francis Inc2015

Solar Hydrogen Production by Amorphous Silicon Photocathodes Coated with a Magnetron Sputter Deposited Mo

Christophe Ballif, Xile Hu, Laurent Liardet, Carlos Gilberto Morales Guio, Björn Niesen

Coupling of Earth-abundant hydrogen evolution catalysts to photoabsorbers is crucial for the production of hydrogen fuel using sunlight. In this work, we demonstrate the use of magnetron sputtering to deposit Mo2C as an efficient hydrogen evolution reactio ...

Amer Chemical Soc2015

The effect of cooling press on the encapsulation properties of crystalline photovoltaic modules: residual stress and adhesion

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

A high-quality encapsulation process is crucial to ensuring the performance and long-term reliability of photovoltaic (PV) modules. In crystalline Si technology-based modules, poly (ethylene-co-vinyl acetate) (EVA) is the most widely used PV encapsulant. I ...

Wiley-Blackwell2015

Amorphous/Crystalline Silicon Interface Passivation: Ambient-Temperature Dependence and Implications for Solar Cell Performance

Christophe Ballif, Bénédicte Demaurex, Stefaan De Wolf, Johannes Peter Seif

Silicon heterojunction (SHJ) solar cells feature amorphous silicon passivation films, which enable very high voltages. We report how such passivation increases with operating temperature for amorphous silicon stacks involving doped layers and decreases for ...

Ieee-Inst Electrical Electronics Engineers Inc2015

Environmental stability of high-mobility indium-oxide based transparent electrodes

Christophe Ballif, Ali Dabirian, Stefaan De Wolf, Monica Morales Masis, Thanaporn Tohsophon

Large-scale deployment of a wide range of optoelectronic devices, including solar cells, critically depends on the long-term stability of their front electrodes. Here, we investigate the performance of Sn-doped In2O3 (ITO), H-doped In2O3 (IO:H), and Zn-dop ...

Amer Inst Physics2015

CH3NH3PbI3 perovskite/silicon tandem solar cells: characterization based optical simulations

Christophe Ballif, Stefaan De Wolf, Björn Niesen

In this study we analyze and discuss the optical properties of various tandem architectures: mechanically stacked (four-terminal) and monolithically integrated (two-terminal) tandem devices, consisting of a methyl ammonium lead triiodide (CH3NH3PbI3) perov ...

Optical Society of America2015

Wire-sawing processes: parametrical study and modeling

Christophe Ballif, Mathijs Pieter van der Meer, Adrien Bidiville

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

Sputtered rear electrode with broadband transparency for perovskite solar cells

Christophe Ballif, Guy Joseph Günter Dubuis, Sylvain Nicolay, Soo-Jin Moon, Arnaud Walter, Stefaan De Wolf, Jérémie Werner, Monica Morales Masis, Björn Niesen, Philipp Friedrich Hermann Löper

Due to their high efficiencies combined with simple and cost-effective device fabrication, perovskite solar cells are promising candidates as top cells in tandem devices. For this application, the perovskite solar cell must be highly transparent at near-in ...

Elsevier2015

Practical silicon deposition rules derived from silane monitoring during plasma-enhanced chemical vapor deposition

Christophe Ballif, Bénédicte Demaurex, Stefaan De Wolf

We clarify the difference between the SiH4 consumption efficiency eta and the SiH4 depletion fraction D, as measured in the pumping line and the actual reactor of an industrial plasma-enhanced chemical vapor deposition system. In the absence of significant ...

American Institute of Physics2015

Light management in thin film silicon solar cells

Christophe Ballif, Franz-Josef Haug

Thin film silicon is an attractive and versatile material for photovoltaics whose manufacturing reached a high level of maturity. Owing to its moderate efficiency compared to crystalline technologies, it should target either power plants with low installat ...

Royal Society of Chemistry2015

Complex Refractive Index Spectra of CH3NH3PbI3 Perovskite Thin Films Determined by Spectroscopic Ellipsometry and Spectrophotometry

Christophe Ballif, Jun Ho Yum, Soo-Jin Moon, Stefaan De Wolf, Michael Elias Stückelberger, Jérémie Werner, Björn Niesen

The complex refractive index (dielectric function) of planar CH3NH3PbI3 thin films at room temperature is investigated by variable angle spectroscopic ellipsometry and spectrophotometry. Knowledge of the complex refractive index is essential for designing ...

Amer Chemical Soc2015

Silver versus white sheet as a back reflector for microcrystalline silicon solar cells deposited on LPCVD-ZnO electrodes of various textures

Christophe Ballif, Franz-Josef Haug, Mathieu Gérard Boccard, Etienne Antoine Julien Moulin

We compare the performance of two back reflector designs on the optoelectrical properties of microcrystalline silicon solar cells. The first one consists of a 5-mu m-thick low-pressure chemical vapor deposition (LPCVD)-ZnO electrode combined with a white s ...

Wiley-Blackwell2015

Plastic and Elastic Strain Fields in GaAs/Si Core-Shell Nanowires

Christophe Ballif, Anna Fontcuberta i Morral, Martin Heiss, Sylvain Dunand, Sonia Conesa Boj, Eleonora Russo

Thanks to their unique morphology, nanowires have enabled integration of materials in a way that was not possible before with thin film technology. In turn, this opens new avenues for applications in the areas of energy harvesting, electronics, and optoele ...

American Chemical Society2014

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

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