Publications by Christophe Ballif

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We explore the limit of absorption enhancement in thin film solar cells obtained by guided mode excitation and we discuss the geometrical and angular dependence of absorption. We consider the modal properties of the cell.

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. ...

The deposition of thin-film silicon solar cells on highly textured substrates results in improved light trapping in the cell. However, the growth of silicon layers on rough substrates can often lead to undesired current drains, degrading performance and re ...

The micromorph solar cell (stack of amorphous and microcrystalline cells) concept is the key for achieving high efficiency stabilized thin film silicon solar cells. We introduce a device structure that allows a better control of the light in-coupling into ...

Combining a Si solar cell with a high-bandgap top cell reduces the thermalization losses in the short wavelength and enables theoretical 1-sun efficiencies far over 30%. We have investigated the fabrication and optimization of Si-based tandem solar cells w ...

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 ...

We present electron- and hole-selective passivating contacts based on wet-chemically grown interfacial SiOx and overlying in-situ doped silicon carbide (SiCx) deposited by plasma-enhanced chemical vapor deposition. After annealing at 850 degrees C, excelle ...

We investigate the influence of refractive index contrast on the light scattering properties of nanotextured interfaces, which serve as front contact for p-i-n thin-film silicon solar cells. We here focus on ZnO surfaces with randomly oriented pyramidal features, known for their excellent light trapping performance. Transparent replicas, with a different refractive index, but practically identical morphology compared to their ZnO masters, were fabricated via nanoimprinting. Within the theoretical framework

Thin hydrogenated amorphous silicon (a-Si:H) films deposited on crystalline silicon (c-Si) surfaces are sensitive probes for the bulk electronic properties of a-Si:H. Here, we use such samples during repeated low-temperature annealing and visible-light soa ...

Recent studies showed that silicon heterojunction (SHJ) solar cells can be prone to potential induced degradation (PID) when encapsulated with a low volume resistivity ethylene vinyl acetate (EVA). We perform PID test in humid conditions (85°C/85% RH) on g ...

Hydrogenated amorphous silicon (a-Si:H) is attractive for radiation detectors because of its radiation resistance and processability over large areas with mature Si microfabrication techniques. While the use of a-Si:H for medical imaging has been very succ ...

We model analytically light harvesting in realistic solar cells by extending a formalism suggested by Deckman et al. [Appl. Phys. Lett. 42, 110968 (1983)], based on tracing of an average ray of light. Arbitrary light scattering schemes and parasitic absorption are implemented in the model, and we validate our approach by comparing with experimental measurements from microcrystalline silicon devices. The intuitive understanding obtained with this extended model is discussed. This approach enables identifying

We investigate rapid thermal processing (RTP) as alternative to the prolonged thermal annealing process used to form tunnel-oxide passivating contacts for silicon solar cells. The thermal treatment is generally followed by hydrogenation to passivate defect ...

This paper addresses three independent approaches to improving the performance of Micromorph® tandem solar cells: 1. Thinner cells for higher throughput in mass-production, 2. Optimum cell design and processes yielding stable efficiencies of 11.5% on as-grown ZnO front contact, and finally 3. The introduction of novel textured glass substrates prepared by Corning Incorporated to improve light-management. As a result of the joint research between Oerlikon Solar- Lab and Corning Incorporated, a Micromorph® ta

To date, none of the predictions that have been made about the emerging BIPV industry have really hit the target. The anticipated boom has so far stalled and despite developing and promoting a number of excellent systems and products, many producers around the world have been forced to quit on purely economic grounds. The authors believe that after this painful cleansing of the market, a massive counter trend will follow, enlivened and carried forward by more advanced PV technologies and ever- stricter clim

A salient characteristic of solar cells is their ability to subject photo-generated electrons and holes to pathways of asymmetrical conductivity-'assisting' them towards their respective contacts. All commercially available crystalline silicon (c-Si) solar ...

Thin-film silicon solar cells often apply a metal back reflector (BR) separated from the silicon layers by a thin rear dielectric of thickness around 80 nm or a white paint combined with a thick rear dielectric of several micrometers. In this work, we investigate the optical performance of microcrystalline silicon (μc-Si:H) solar cells applying BRs of various topographies. In contrast to a standard 80 nm-ZnO/Ag BR design, for which the BR nearly strictly follows the texture of the underlying μc-Si:H layers,

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 ...

The defects located at surface and grain boundaries are generally agreed to be the key factors limiting the power conversion efficiency and operational stability of the halide perovskite solar cells. Therefore, new techniques for surface and grain boundaries passivation are being continuously developed and studied. In this work, we investigate the impact of diffuse coplanar surface barrier discharge (DCSBD) nitrogen plasma treatment on the photoluminescence properties and performance of halide perovskite th

Christophe Ballif

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Light Trapping Limit Revisited: How do Guided Modes Enhance Light Absorption in Solar Cells?

Solar cell and its production process

Resistive interlayer for improved performance of thin film silicon solar cells on highly textured substrate

Highly Conductive and Broadband Transparent Zr-Doped In2O3 as Front Electrode for Solar Cells (vol 8, pg 1202, 2018)

Asymmetric intermediate reflector for tandem micromorph thin film silicon solar cells

Realization of GaInP/Si Dual-Junction Solar Cells With 29.8% 1-Sun Efficiency

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

Crystalline Silicon Solar Cells With Coannealed Electron- and Hole-Selective SiCx Passivating Contacts

A New Approach to Light Scattering from Nanotextured Interfaces for Thin-Film Silicon Solar Cells

Is light-induced degradation of a-Si:H/c-Si interfaces reversible?

Optimized Module Packaging for Silicon Heterojunction Solar Cells and Increased PID Resistance

Review of amorphous silicon based particle detectors: the quest for single particle detection

Light trapping in solar cells: Analytical modeling

Impact of Rapid Thermal Processing on Bulk Lifetime and Surface Recombination Velocity of Crystalline Silicon With Passivating Tunnel Oxide Contacts

Recent Developments of High Efficiency Micromorph tandem solar cells in KAI-M PECVD reactors

Building Integrated Photovoltaics (BIPV): Review, Potentials, Barriers and Myths

Efficient silicon solar cells with dopant-free asymmetric heterocontacts

Thin-film silicon solar cells applying optically decoupled back reflectors

Sputtered rear electrode with broadband transparency for perovskite solar cells

Defect Passivation via Plasma Modification of Lead Halide Perovskite Thin Films