Publications by Christophe Ballif

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Building integrated photovoltaics (BIPV) operate in a unique environment compared with field-mounted systems and may experience elevated temperatures and recurrent or persistent shading. These stresses are expected to accelerate degradation, but there are ...

37th European Photovoltaic Solar Energy Conference and Exhibition; 206-207 We present a firing-through metallisation approach for n-type passivating rear contacts that consist of a tunnelling oxide and an n-doped bilayer of a-SiOx and μc-Si. We find implied Voc up to 738 mV and contact resistivities as low as 20 mΩcm2. Implemented into 6-inch solar cells with a B-diffused emitter on the front, the best cell showed a Voc of 687 mV, FF 79.4 % and an overall efficiency of 22.2 %, proving the compatibility with

We review laser applications in thin-film photovoltaics (thin-film Si, CdTe, and Cu(In,Ga)Se2 solar cells). Lasers are applied in this growing field to manufacture modules, to monitor Si deposition processes, and to characterize opto-electrical properties ...

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 ...

We propose the use of transparent replicated random nanostructures fabricated via nanoimprinting on glass as next-generation superstrates for thin film silicon solar cells.We validate our approach by demonstrating short-circuit current densities for p-i-n hydrogenated microcrystalline silicon solar cells as high as for state-of-the-art nanotextured ZnO front electrodes. Our methodology opens exciting possibilities to integrate a large variety of nanostructures into p-i-n solar cells and allows to systematic

The use of intrinsic silicon oxide as a buffer layer at the p-i interface of thin-film silicon solar cells is shown to provide significant advantages. For microcrystalline silicon solar cells, when associated with highly crystalline i-layers deposited at h ...

Imperfect internal reflectance of near-bandgap light reduces the performance of all solar cells, and becomes increasingly detrimental as absorbers become thinner. We consider light incident on the silicon/dielectric/metal structure at the back of rear-pass ...

Silicon heterojunction solar cells consist of crystalline silicon (c-Si) wafers coated with doped/intrinsic hydrogenated amorphous silicon (a-Si:H) bilayers for passivating-contact formation. Here, we unambiguously demonstrate that carrier injection either ...

High-temperature compatible passivating contacts based on phosphorus doped polysilicon (poly-Si(n)) on a thin silicon oxide, employed on the rear side of bifacial n-PERT like solar cells provide an efficiency increase while being compatible with current ph ...

Microcrystalline silicon (mc-Si:H) cells can reach efficiencies up to typically 10% and are usually incorporated in tandem micromorph devices. When cells are grown on rough substrates, ‘‘cracks’’ can appear in the mc-Si:H layers. Previous works have demons ...

Angle resolved measurements of the external quantum efficiency of n-i-p single junction amorphous solar cell deposited on a grating structure show clearly defined peaks of enhanced photocurrent in the weakly absorbing region between 1.6 and 2.15 eV. We explain these absorption phenomena and their angular variation with the excitation of guided modes via grating coupling. Calculation using an equivalent flat multilayer system permits to relate the theoretical values with the experimental data.

In this study, we present dopant-free back contact heterojunction silicon solar cells employing MoOx and MgFx based stacks as hole-and electron-selective contacts deposited using a thermal evaporation process at low temperature. Only two masking steps and ...

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. ...

The silane dissociation efficiency, or depletion fraction, is an important plasma parameter by means of which the film growth rate and the amorphous-to-microcrystalline silicon transition regime can be monitored in situ. In this letter we implement a homeb ...

This paper proposes a method to spatially model and compare charging needs on the European scale considering local disparities in population density, distance to city centres, car ownership and mobility habits. Mobility habits are modelled across Europe in ...

We discuss the optical properties of non-degraded and anodically degraded boron-doped zinc oxide (ZnO:B) deposited by low-pressure chemical vapour deposition on soda-lime glass. The optical model used to simulate the infrared reflectance in the wavelength ...

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 ...

We use a new in-house, large area and automated deposition system: the usable deposition area is 410 × 520 mm with RF-frequency of 40 MHz. We deposit intrinsic a-Si:H layer on flat p-type or n-type c-Si wafers after performing an HF dip. The overall recomb ...

This study analyses 30+ years of PV performance in Switzerland, highlighting the reliability of early 90s modules. It examines outdoor system- and indoor module-level data, emphasising the importance of BOM and the benefits of lower temperatures. ...

Flexible large-area organic light-emitting diodes (OLEDs) require highly conductive and transparent anodes for efficient and uniform light emission. Tin-doped indium oxide (ITO) is the standard anode in industry. However, due to the scarcity of indium, alt ...

Christophe Ballif

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Long-Term Performance and Shade Detection in Building Integrated Photovoltaic Systems

Firing-Through Metallisation of PERT-Like Cells Using μc-Si(n) as Thin Rear Side Full Area Passivating Contact

Laser applications in thin-film photovoltaics

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

Efficient light management scheme for thin film silicon solar cells via transparent random nanostructures fabricated by nanoimprinting

Silicon oxide buffer layer at the p-i interface in amorphous and microcrystalline silicon solar cells

Improving metal reflectors by suppressing surface plasmon polaritons: a priori calculation of the internal reflectance of a solar cell

Light-induced performance increase of silicon heterojunction solar cells

22.8% full-area bifacial n-PERT solar cells with rear side sputtered poly-Si (n) passivating contact

Microcrystalline silicon solar cells: effect of substrate temperature on cracks and their role in post-oxidation

Photocurrent increase in n-i-p thin film silicon solar cells by guided mode excitation via grating coupler

22% Efficient Dopant-free Interdigitated Back Contact Silicon Solar Cells

Back-Contacted Silicon Heterojunction Solar Cells: Optical-Loss Analysis and Mitigation

Infrared laser-based monitoring of the silane dissociation during deposition of silicon thin films

Mapping the charging demand for electric vehicles in 2050 from mobility habits

Optical properties of anodically degraded ZnO

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

Ultra-high quality surface passivation of crystalline silicon wafers in large area parallel plate reactor at 40 MHz

Three decades, three climates: environmental and material impacts on the long-term reliability of photovoltaic modules

An Indium-Free Anode for Large-Area Flexible OLEDs: Defect-Free Transparent Conductive Zinc Tin Oxide