Aïcha Hessler-Wyser

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The stability of Nd-nickelate, considered as an alternative solid oxide fuel cell (SOFC) cathode material, was evaluated in this work on its tolerance towards contaminants. Symmetrical cells with Nd1.95NiO4+δ (NNO) electrodes on gadolinia-doped ceria electrolyte supports were monitored over time-spans of 1000 h under polarisation in an air-flux with deliberate chromium contamination. Impedance spectroscopy pointed out a polarization increase with time by the growth of the low frequency arc describing the el

Full-area passivating contacts based on SiOx/poly-Si stacks are key for the new generation of industrial silicon solar cells substituting the passivated emitter and rear cell (PERC) technology. Demonstrating a potential efficiency increase of 1 to 2% compa ...

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 ...

A solid oxide fuel (SOFC) cogenerates heat and electricity with high efficiency. Electricity is produced by the electrochemical reaction of a fuel (H2, CO, CH4) and an oxidant gas (O2, air). The SOFC standard design is based on an anode-supported electrolyte. The anode is composed of yttria-stabilized zirconia (YSZ) and nickel oxide (NiO). NiO is reduced in situ into metallic nickel during the first use of the fuel cell. Porosity is formed to compensate the volume shrinkage induced by the reduction (40 vol%

Light-trapping textures were produced in hyperbranched polymer (HBP) silica nanocomposites using a UV-nanoimprint lithography (UVNIL) replication method, either in batch or roll-to-roll processes. The hardness of the HBP was found to increase by a factor o ...

Performance degradation data obtained on single solid oxide fuel cells tested at 850°C with air and humidified H2 and using Ni-YSZ anode supported cells are presented. Microscopic investigation is carried out on both anode and cathode to quantify variation ...

Correlating the microstructure of an energy conversion device to its performance is often a complex exercise, notably in solid oxide fuel cell research. Solid oxide fuel cells combine multiple materials and interfaces that evolve in time due to high operat ...

Halide-perovskite semiconductors have a high potential for use in single-junction and tandem solar cells. Despite their unprecedented rise in power conversion efficiencies (PCEs) for photovoltaic (PV) applications, it remains unclear whether perovskite sol ...

Tandem solar cells are a key technology for exceeding the theoretical efficiency limit of single-junction cells. One of the most promising combinations is the silicon-perovskite tandem cells, considering their potential for high efficiency, fabrication on ...

Two fundamental requirements of transparent conductive oxides are high conductivity and low optical absorptance, properties strongly dependent on the free-carrier concentration of the film. The free carrier concentration is usually-tuned by the addition of ...

Spatially resolved analyses, by energy-dispersive X-ray spectroscopy (EDS) scanning electron microscopy (SEM), allowed the quantification of exogenous Si contamination in a solid oxide fuel cell (SOFC) cathode after operation. The Si quantification, taking ...

Degradation observed on long term stack tests may be explained in part by microstructural changes of the electrodes. Particularly at the anode side, the coarsening of nickel particles will affect its performances. Increasing the metal particle size will first diminishes the Three-Phase Boundary (TPB) where fuel oxidation takes place, and secondly decrease the electronic conductivity [1]. In order to quantify the changes in anode microstructure, SEM images analysis is used. Some techniques can be time consum

Up-scalable coating processes need to be developed to manufacture efficient and stable perovskite-based solar modules. In this work, we combine two Lewis base additives (N,N′-dimethylpropyleneurea and thiourea) to fabricate high-quality Cs0.15FA0.85PbI3 pe ...

Environmental transmission electron microscopy was used to characterize in situ the reduction and oxidation of nickel from a Ni/YSZ solid oxide fuel cell anode support between 300-500°C. The reduction is done under low hydrogen pressure. The reduction init ...

A multifunctional light management layer for perovskite solar cells (PSCs) is presented, made from anisotropic pectin cryogel infiltrated with poly(methyl methacrylate), further enhanced by the incorporation of 2,2′,7,7′‐tetrabromo‐9,9′‐spirobifluorene. The effectiveness of the composite layers is evaluated by attaching them to the front glass surface of the PSCs. As a result, the current density of the functionalized PSC increases by an average of 4.4 ± 0.3% relative to pristine PSCs. The improvement is cr

Nickel-Titanium (NiTi) shape memory alloys are often used in medical component devices, for instance as guide wires for neurological surgery applications. Manufacturing of such devices becomes more and more challenging, especially considering the need to join them with other metals, like Stainless Steel (SS). Laser welding is a promising technique to realize and to guaranty the mechanical stability of dissimilar metal welds. However, inherent differences in chemical compositions may lead to fracture of the

Highly transparent electrodes with a well-tuned refractive index are essential for a wide range of optoelectronic devices, such as light emitting diodes and solar cells. Here, it is shown that the transparency of ZnO:Al can be improved and its refractive i ...

Electric vehicles (EVs) currently dominate the sales in the automotive market. A big leap in this market can be made by developing a photovoltaic product that can be integrated to an EV, as it can boost the driving range of the EV while reducing the chargi ...

Microstructural evolution in solid oxide fuel cell (SOFC) cermet anodes has been investigated using X-ray nanotomography along with differential absorption imaging. SOFC anode supports composed of Ni and yttria-stabilized zirconia (YSZ) were subjected to e ...

Polysilicon recombination junctions whose n-type bottom layers double as a passivating contact to the silicon surface are investigated. Such recombination junctions are a key element in the interconnection of tandem devices with a silicon bottom cell, and ...

Aïcha Hessler-Wyser

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Nd-Nickelate Solid Oxide Fuel Cell Cathode Sensitivity to Cr and Si Contamination

Development and characterization of N2O-plasma oxide layers for high-temperature p-type passivating contacts in silicon solar cells

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

Solid oxide fuel cell redox instability characterized by in situ transmission electron microscopy

UV-nanoimprint lithography and large area roll-to-roll texturization with hyperbranched polymer nanocomposites for light-trapping applications

Experimental and Theoretical Investigation of Degradation Mechanisms in SOFC Electrodes

Operando analysis of a solid oxide fuel cell by environmental transmission electron microscopy

Linking Nanoscopic Insights to Millimetric-Devices in Formamidinium-Rich Perovskite Photovoltaics

Passivating contact-based tunnel junction Si solar cells using machine learning for tandem cell applications

Direct Imaging of Dopant Distribution in Polycrystalline ZnO Films

Glass-Forming Exogenous Silicon Contamination in Solid Oxide Fuel Cell Cathodes

Methods for quantification of anode support microstructure

Blade-Coating of High Crystallinity Cesium-Formamidinium Perovskite Formulations

In situ Reduction and Oxidation of Nickel from Solid Oxide Fuel Cells in a Transmission Electron Microscope

Enhancing the Performance and Photostability of Perovskite Solar Cells with a Multifunctional Light‐Management Composite

Characterisation of Laser Welds, between Nitinol and Stainless Steel Wires

Tuning the Optoelectronic Properties of ZnO:Al by Addition of Silica for Light Trapping in High-Efficiency Crystalline Si Solar Cells

Stress tolerance of lightweight glass-free PV modules for vehicle integration

Three-dimensional microstructural changes in the Ni-YSZ solid oxide fuel cell anode during operation

Passivating Polysilicon Recombination Junctions for Crystalline Silicon Solar Cells