Publications de Christophe Ballif

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We present a comprehensive scalar light-scattering model for the optical simulation of silicon thin film solar cells. The model integrates coherent light propagation in thin layers with a direct, noniterative treatment of light scattered at rough layer interfaces. The direct solution approach ensures computational efficiency, which is a key advantage for extensive calculations in the context of evaluation of different cell designs and parameter extraction. We validate the model with experimental external qu

We study the effects of a-Si:H and mu c-Si:H covering layers and an H-2 treatment on the characteristics of mu c-Si:H thin film solar cells deposited in open single chamber very high frequency plasma enhanced chemical vapor deposition systems. Secondary io ...

This paper gives new insights into the role of both the microstructure and the interfaces in microcrystalline silicon (μc- Si) single-junction solar cells. A 3-D tomographic reconstruction of a μc-Si solar cell reveals the 2-D nature of the porous zones, which can be present within the absorber layer. Tomography thus appears as a valuable technique to provide insights into the μc- Si microstructure. Variable illumination measurements enable to study the negative impact of such porous zones on solar cells pe

Formamidinium (FA) cations commonly used in perovskite semiconductors tend to form sym-triazine when sublimed in vacuum, a process that hampers the deposition process. Here we find that ammonia, when used as a carrier gas for formamidinium halides transport, cleaves the sym-triazine ring back to formamidinium, hence enhancing the deposition efficiency.

The necessity to reduce carbon emissions has pushed European institutions to foster the adoption - for new buildings - of Nearly Zero Energy Buildings, which need to minimize energy consumption with energy generated on site. This opens up an enormous poten ...

We apply a Fourier-scattering model to describe light scattering in solar cells with textured surfaces. For the size and inclination angle of typical micro-textures, scattering may occur into large angles. This makes the model prone to paraxial errors. We ...

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 ...

The chemical compositions of defective regions in microcrystalline thin film Si solar cells are studied using energy-dispersive X-ray spectroscopy and electron energy-loss spectroscopy (EELS) in the scanning transmission electron microscope. Nanometer-reso ...

We calculate the maximal absorption enhancement obtainable by guided mode excitation in a weakly absorbing dielectric slab over wide wavelength ranges. The slab mimics thin film silicon solar cells in the low absorption regime. We consider simultaneously w ...

Silicon solar cells based on high temperature passivating contacts are becoming mainstream in the photovoltaic industry. Here, we developed a high-quality boron-doped poly-silicon hole contact. When combined with a co-processed phosphorus-doped poly-silico ...

The electricity self-consumption level of a family household is determined both experimentally and by modelling. The effect of rapid fluctuation in PV production and electricity demand, and especially the effect of the temporal resolution of their measurements, are studied. For accurate determination of the self-consumption level, temporal resolution of at least 30 s for the load profile and at least 10 min for the PV production measurements are suggested. The effect of temporal resolution becomes negligibl

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 ...

The effects of a fluorine doped tin oxide (FTO) electrode, titanium dioxide (TiO2-x) blocking layer (BL) and perovskite (methyl ammonium lead triiodide) preparation on the overall properties of the photovoltaic cells have been studied. The FTO electrode wa ...

Because building-integrated photovoltaic (BIPV) modules are fully integrated into a building envelope, the back of the module can be exposed to little or no ventilation, resulting in increased operating temperatures. As the temperature increases, the perfo ...

Over the last years, the operational stability of perovskite solar cells has been significantly improved by compositional engineering, interface modification, and improved encapsulation techniques. However, irreversible degradation is still ubiquitously ob ...

Polycrystalline Boron-doped ZnO films deposited by low pressure chemical vapor deposition technique are developed for their use as transparent contacts for thin-film silicon solar cells. The size of the columnar grains that constitute the ZnO films is rela ...

We study the high-rate deposition of microcrystalline silicon in a large-area plasma-enhanced chemical-vapor-deposition (PECVD) reactor operated at 40.68 MHz, in the little-explored process conditions of high-pressure and high-silane concentration and depl ...

This short communication highlights our latest results towards high-efficiency microcrystalline silicon single-junction solar cells. By combining adequate cell design with high-quality material, a new world record efficiency was achieved for single-junctio ...

In this article, we report on the use of transmission electron microscopy (TEM) for the fabrication of high-performance textured amorphous/crystalline silicon (a-Si:H/c-Si) heterojunction (HJ) solar cells. Whereas classical thin-film characterization techn ...

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 ...

Christophe Ballif

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Extended light scattering model incorporating coherence for thin-film silicon solar cells

Enhancement of microcrystalline n-i-p solar cell performance via use of pre-covering layers and H-2 treatment

On the Interplay Between Microstructure and Interfaces in High-Efficiency Microcrystalline Silicon Solar Cells

Ammonia-assisted vapour transport deposition of formamidinium salts for perovskite thin films

Stability of inks used for masking metallic interconnects in BIPV modules

Fourier light scattering model for treating textures deeper than the wavelength

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

Compositional study of defects in microcrystalline silicon solar cells using spectral decomposition in the scanning transmission electron microscope

Light trapping in solar cells at the extreme coupling limit

Rear textured p-type high temperature passivating contacts and their implementation in perovskite/silicon tandem cells

Effect of the Fluctuations of PV Production and Electricity Demand on the PV Electricity Self-Consumption

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

Progression towards high efficiency perovskite solar cells via optimisation of the front electrode and blocking layer

Correlating long-term performance and aging behaviour of building integrated PV modules

I-2 vapor-induced degradation of formamidinium lead iodide based perovskite solar cells under heat-light soaking conditions

Opto-electronic properties of rough LP-CVD ZnO:B for use as TCO in thin-film silicon solar cells

High-rate deposition of microcrystalline silicon in a large-area PECVD reactor and integration in tandem solar cells

High-efficiency microcrystalline silicon single-junction solar cells

Textured silicon heterojunction solar cells with over 700mV open-circuit voltage studied by transmission electron microscopy

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