Publications by Christophe Ballif

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In this article, we investigate the effect of prolonged light exposure on silicon heterojunction solar cells. We show that, although light exposure systematically improves solar cell efficiency in the case of devices using intrinsic and p-type layers with ...

Here high-efficiency (above 21%) large-area silicon heterojunction solar cells with atomic layer deposited ZnO:Al as front- or back-side transparent conducting oxide are demonstrated. Photoconductance decay measurements indicate that the excellent chemical ...

In silicon heterojunction (SHJ) solar cells, one factor limiting efficiency is "parasitic absorption" from amorphous silicon (a-Si) at the front surface. Thus, discovery of a transparent hole-selective contact to replace p-type a-Si is a promising area of ...

The link between sub-bandgap states and optoelectronic properties is investigated for amorphous zinc tin oxide (a-ZTO) thin films deposited by RF sputtering. a-ZTO samples were annealed up to 500 °C in oxidizing, neutral, and reducing atmospheres before ch ...

The mechanisms and environmental influences that cause photovoltaic modules performance degradation are poorly understood, but it is well known that water vapour is deeply implicated in the degradation process. Indeed, some layers and interfaces of thin film modules can be moisture sensitive and depending on the processing conditions, they degrade after exposure to damp heat conditions (85°C, 85% relative humidity) [1]. Transparent conductive oxides (TCO), as used in CIGS or thin silicon film cells play a p

We examine damage-free transparent-electrode deposition to fabricate high-efficiency amorphous silicon/crystalline silicon heterojunction solar cells. Such solar cells usually feature sputtered transparent electrodes, the deposition of which may damage the ...

Reducing wafer thickness while increasing power conversion efficiency is the most effective way to reduce cost per Watt of a silicon photovoltaic module. Within the European project 20 percent efficiency on less than 100-mu m-thick, industrially feasible c ...

The boron-tailing effect in hydrogenated amorphous silicon (a-Si:H) solar cells describes the reduced charge collection specifically in the blue part of the spectrum for absorber layers deposited above a critical temperature. This effect limits the device ...

This paper reports a facile method to prepare a textured surface with combined micron- and nano-scale surface features, which is used as master for nano-imprinting process to obtain transparent front electrodes in thin-film silicon tandem cells. The micron ...

Silicon heterojunction solar cells have record-high open-circuit voltages but suffer from reduced short-circuit currents due in large part to parasitic absorption in the amorphous silicon, transparent conductive oxide (TCO), and metal layers. We previously identified and quantified visible and ultraviolet parasitic absorption in heterojunctions; here, we extend the analysis to infrared light in heterojunction solar cells with efficiencies exceeding 20%. An extensive experimental investigation of the TCO lay

The decentralisation and unpredictability of new renewable energy sources require rethinking our energy system. Data-driven approaches, such as reinforcement learning (RL), have emerged as new control strategies for operating these systems, but they have n ...

Despite the progress in the engineering of structures to enhance photocurrent in thin film solar cells, there are few comprehensive studies which provide general and intuitive insight into the problem of light trapping. Also, lack of theoretical propositio ...

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 ...

The electrification of the transport sector is a key element in decarbonizing our societies. However, energy systems will have to cope with additional electricity demand due to the charging needs of electric vehicles (EVs) together with the integration of ...

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 ...

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 suited to face these energy challenges. It is now established that the low thin film photovoltaic panels production costs will allow, even in continental climate, to reach low electricity cost, providing easy installation, public acceptance and high reliabil

Being void-free is an important criterion for the quality control of photovoltaic (PV) modules after encapsulation. The encapsulation process of PV modules with Ethylene Vinyl Acetate (EVA) polymer is complex, due to the time-dependent processing conditions and the material properties caused by continuous heat transfer and chemical reactions such as crosslinking. Hence, an in-depth understanding on the void evolution mechanism is challenging yet critical for obtaining high-quality, durable void-free PV modu

This paper reports on the final main results of the Flexcellence project. The project was running for 3 years and its goal was the development of equipments and processes for cost-effective roll-to-roll production of high-efficiency flexible thin-film sili ...

The global energy transition aims to decarbonise both transportation and electricity generation to mitigate climate change and reduce reliance on fossil fuels. Electrification of private transportation, through the adoption of electric vehicles (EVs), presents a promising pathway to achieving the first objective. Concurrently, the rapid advancement and cost reduction of photovoltaic (PV) technology have positioned solar energy as a viable solution for renewable electricity production. This review paper synt

In this work, a novel type of substrate for thin-film silicon solar cells is studied. The substrate has the advantage of being physically flat to allow the growth of cells with excellent material quality while being optically rough for enhanced light trapping that leads to high short-circuit current density. The substrate is made of rough zinc oxide (ZnO) which is grown on a flat silver reflector. The ZnO is then covered with amorphous silicon and the stack is polished to expose the tips of the pyramidal Zn

Christophe Ballif

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Influence of Light Soaking on Silicon Heterojunction Solar Cells With Various Architectures

Rear-emitter silicon heterojunction solar cells with atomic layer deposited ZnO:Al serving as an alternative transparent conducting oxide to In2O3:Sn

Linking simulation and synthesis of nickel oxide hole-selective contacts for silicon heterojunction solar cells

Enhancing the optoelectronic properties of amorphous zinc tin oxide by subgap defect passivation: A theoretical and experimental demonstration

DAMP HEAT STABILITY OF TRANSPARENT CONDUCTIVE ZINC OXIDES: ROLE OF ENCAPSULANTS AND PROTECTIVE LAYERS

Atomic-Layer-Deposited Transparent Electrodes for Silicon Heterojunction Solar Cells

Manufacturing 100-mu m-thick silicon solar cells with efficiencies greater than 20% in a pilot production line

The boron-tailing myth in hydrogenated amorphous silicon solar cells

Facile preparation of micron- and nano-scale textured master for nano-imprinting front electrode in thin-film silicon tandem cells with improved light trapping

Infrared light management in high-efficiency silicon heterojunction and rear-passivated solar cells

Reinforcement Learning for Joint Design and Control of Battery-PV Systems

Understanding of photocurrent enhancement in real thin film solar cells: towards optimal onedimensional gratings

Wire-sawing processes: parametrical study and modeling

From PV to EV: Mapping the Potential for Electric Vehicle Charging with Solar Energy in Europe

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

New challenges in solar architectural innovation

Modeling of voids evolution in the encapsulation process of photovoltaic modules

FINAL RESULTS OF THE EUROPEAN PROJECT FLEXCELLENCE ROLL TO ROLL TECHNOLOGY FOR THE PRODUCTION OF HIGH EFFICIENCY LOW COST THIN FILM SOLAR CELLS

Benefits of Coupling Electric Vehicle Charging with Photovoltaic Electricity Production: A Global Overview

Experimental study of flat light-scattering substrates in thin-film silicon solar cells