Publications by Aïcha Hessler-Wyser

Beyond Flat: Undulated Perovskite Solar Cells on Microscale Si Pyramids by Solution Processing

Christophe Ballif, Aïcha Hessler-Wyser, Mostafa Rabie Shlaly Bahr Othman, Kerem Artuk, Deniz Türkay, Christian Michael Wolff

Microscale pyramids of silicon solar cells are often considered incompatible with solution-processed perovskite films. Thus, solution processing has mainly been used with submicron pyramids that are buried under thick perovskite films with flattened front ...

AMER CHEMICAL SOC2025

Aryl-Acetylene Layered Hybrid Perovskites in Photovoltaics

Christophe Ballif, Aïcha Hessler-Wyser, Michael Graetzel, Ursula Röthlisberger, Mostafa Rabie Shlaly Bahr Othman, Masaud Hassan S Almalki, Fatemeh Ansari, Felix Thomas Eickemeyer, Lukas Pfeifer, Christian Michael Wolff, Nikolaos Lempesis, Virginia Carnevali

Metal halide perovskites have shown exceptional potential in converting solar energy to electric power in photovoltaics, yet their application is hampered by limited operational stability. This stimulated the development of hybrid layered (two-dimensional, ...

WILEY-V C H VERLAG GMBH2025

Making from Breaking: Degradation Inversion Enables Vapor-Phase Synthesis of Halide Perovskites in Ambient Conditions

Christophe Ballif, Aïcha Hessler-Wyser, Mostafa Rabie Shlaly Bahr Othman, Kerem Artuk, Christian Michael Wolff, Austin George Kuba

Vapor phase deposition of formamidinium-rich perovskites is hampered by the decomposition of formamidine in the vapor phase. We use the reversibility of this reaction to establish a dynamic equilibrium that enables the vapor-phase synthesis of formamidiniu ...

American Chemical Society (ACS)2025

Suppression of Stacking Faults for Stable Formamidinium-Rich Perovskite Absorbers

Christophe Ballif, Aïcha Hessler-Wyser, Ursula Röthlisberger, Mostafa Rabie Shlaly Bahr Othman, Kerem Artuk, Victor Carle Adrien Boureau, Christian Michael Wolff, Nikolaos Lempesis, Virginia Carnevali, Lorenzo Agosta, Austin George Kuba

The poor intrinsic perovskite absorber stability is arguably a central limitation challenging the prospect of commercialization for photovoltaic (PV) applications. Understanding the nanoscopic structural features that trigger instabilities in perovskite ma ...

WILEY-V C H VERLAG GMBH2025

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

Christophe Ballif, Aïcha Hessler-Wyser, Antonin Faes, Jacques Levrat, Matthieu Despeisse, Gianluca Cattaneo, Fahradin Mujovi, Umang Bhupatrai Desai

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 ...

Edp Sciences S A2024

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

Christophe Ballif, Aïcha Hessler-Wyser, Franz-Josef Haug, Julien Hurni, Ezgi Genç, Sofia Libraro, Audrey Marie Isabelle Morisset, David Fernando Reyes Vasquez

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 ...

American Chemical Society (ACS)2024

Assessing the Influence of Illumination on Ion Conductivity in Perovskite Solar Cells

Christophe Ballif, Aïcha Hessler-Wyser, Mostafa Rabie Shlaly Bahr Othman, Christian Michael Wolff

Whether illumination influences the ion conductivity in lead-halide perovskite solar cells containing iodide halides has been an ongoing debate. Experiments to elucidate the presence of a photoconductive effect require special devices or measurement techni ...

2024

Bifacial perovskite/silicon heterojunction tandem solar cells based on FAPbI3-based perovskite via hybrid evaporation-spin coating

Christophe Ballif, Aïcha Hessler-Wyser, Mounir Driss Mensi, Mostafa Rabie Shlaly Bahr Othman, Kerem Artuk, Deniz Türkay, Christian Michael Wolff

Combining the two technologies of tandem solar cells and bifacial solar cells has a great potential to maximize energy harvesting while minimizing material and surface usage. Mid-bandgap perovskites (1.50–1.60 eV) are important for fulfilling current match ...

Elsevier2024

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

Christophe Ballif, Aïcha Hessler-Wyser, Quentin Thomas Jeangros, Mostafa Rabie Shlaly Bahr Othman

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 ...

Wiley-V C H Verlag Gmbh2024

Interactions between aluminium and fired passivating contacts during fire-through metallization (vol 249, 112051, 2023)

Christophe Ballif, Aïcha Hessler-Wyser, Antoine Descoeudres, Franz-Josef Haug, Mario Joe Lehmann, Andrea Ingenito, Sofia Libraro

Elsevier2024

A Universal Perovskite/C60 Interface Modification via Atomic Layer Deposited Aluminum Oxide for Perovskite Solar Cells and Perovskite-Silicon Tandems

Christophe Ballif, Aïcha Hessler-Wyser, Mounir Driss Mensi, Mostafa Rabie Shlaly Bahr Othman, Kerem Artuk, Deniz Türkay, Christian Michael Wolff

The primary performance limitation in inverted perovskite-based solar cells is the interface between the fullerene-based electron transport layers and the perovskite. Atomic layer deposited thin aluminum oxide (AlOX) interlayers that reduce nonradiative re ...

Wiley-V C H Verlag Gmbh2024

Colouring solutions for building integrated photovoltaic modules: A review

Christophe Ballif, Aïcha Hessler-Wyser, Antonin Faes, Alejandro Borja Block, Umang Bhupatrai Desai

The conflict between PV installations and other land uses, such as forestry or agriculture, highlights the urgency for alternative solutions. Integrating PV technology into the built environment is a compelling strategy to mitigate these challenges, enabli ...

2024

Blade-Coating of High Crystallinity Cesium-Formamidinium Perovskite Formulations

Christophe Ballif, Aïcha Hessler-Wyser, Mostafa Rabie Shlaly Bahr Othman, Christian Michael Wolff, Anaël Morgane Jaffrès

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 ...

2024

Nanostructure and Optical Property Tailoring of Zinc Tin Nitride Thin Films through Phenomenological Decoupling: A Pathway to Enhanced Control

Aïcha Hessler-Wyser, Johann Michler, Amit Sharma, Daniele Casari, Caroline Hain, Thomas Nelis

This work addresses the need for precise control of thin film sputtering processes to enable thin film material tailoring on the example of zinc tin nitride (ZTN) thin films deposited via microwave plasma-assisted high power reactive magnetron sputtering ( ...

Amer Chemical Soc2024

Improving the photo-stability of triple cation perovskite solar cells using chromophore-infused optically transparent Pectin/polymethyl methacrylate composite

Christophe Ballif, Aïcha Hessler-Wyser, Mostafa Rabie Shlaly Bahr Othman, Christian Michael Wolff

Perovskite solar cells (PSCs) show great promise due to their high efficiency and low manufacturing costs, yet they encounter notable challenges such as optical losses and stability issues, mainly due to high surface reflection and degradation from UV irra ...

FUNDACIO DE LA COMUNITAT VALENCIANA SCITO2024

Alleviating nanostructural phase impurities enhances the optoelectronic properties, device performance and stability of cesium-formamidinium metal-halide perovskites

Christophe Ballif, Aïcha Hessler-Wyser, Quentin Thomas Jeangros, Beat Ruhstaller, Mostafa Rabie Shlaly Bahr Othman, Daniel Anthony Jacobs, Christian Michael Wolff, Anaël Morgane Jaffrès, Austin George Kuba

The technique of alloying FA+ with Cs+ is often used to promote structural stabilization of the desirable alpha-FAPbI3 phase in halide perovskite devices. However, the precise mechanisms by which these alloying approaches improve the optoelectronic quality ...

Royal Soc Chemistry2024

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

Christophe Ballif, Aïcha Hessler-Wyser, Franz-Josef Haug, Audrey Marie Isabelle Morisset, Hyunjung Park

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 ...

ELSEVIER2023

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

Stefan Diethelm, Aïcha Hessler-Wyser, Jan Van Herle, Quentin Thomas Jeangros, Cédric Frantz

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 ...

Nature Portfolio2023

Understanding and mitigating resistive losses in fired passivating contacts: role of the interfaces and optimization of the thermal budget

Christophe Ballif, Aïcha Hessler-Wyser, Franz-Josef Haug, Luca Massimiliano Antognini, Julien Hurni, Ezgi Genç, Sofia Libraro, Audrey Marie Isabelle Morisset

This work presents a study of p-type passivating contacts based on SiCx formed via a rapid thermal processing (RTP) step, using conditions compatible with the firing used to sinter screen-printed metallization pastes in industry. The contributions of the t ...

Elsevier2023

Interactions between aluminium and fired passivating contacts during fire-through metallization

Christophe Ballif, Aïcha Hessler-Wyser, Franz-Josef Haug, Mario Joe Lehmann, Sofia Libraro

Replacing silver metallization with earth-abundant materials in Si solar cells is a critical step towards the sustainable growth of photovoltaics. In this work, we investigate fire-through processes using Al for the metallization of solar cells with p-type ...

ELSEVIER2023