Publications by Peter Joseph Fiala

Interface passivation for 31.25%-efficient perovskite/silicon tandem solar cells

Christophe Ballif, Mounir Driss Mensi, Quentin Thomas Jeangros, Mathieu Gérard Boccard, Peter Joseph Fiala, Quentin Jean-Marie Armand Guesnay, Daniel Anthony Jacobs, Kerem Artuk, Xin Yu Chin, Deniz Türkay, Christian Michael Wolff

Silicon solar cells are approaching their theoretical efficiency limit of 29%. This limitation can be exceeded with advanced device architectures, where two or more solar cells are stacked to improve the harvesting of solar energy. In this work, we devise ...

American Association for the Advancement of Science2023

Correlating light-induced deep defects and phase segregation in mixed-halide perovskites

Quentin Thomas Jeangros, Jakub Holovsky, Peter Joseph Fiala, Xin Yu Chin, Christian Michael Wolff

Mixed-halide perovskites are highly promising materials for tandem solar cells. The phenomenon of phase segregation, however hinders their application. Here, we combine Fourier-Transform photocurrent spectroscopy with photoluminescence and current density- ...

Royal Society of Chemistry2022

Material Development for Perovskite/Silicon Tandem Photovoltaics

Peter Joseph Fiala

The developed world is built on the fact that energy is readily available and functionally infinite. The electricity from the wall, the gas at the station, and the heat in our homes are reliable and low-cost. But this comfort is so far only possible throug ...

EPFL2022

Nano-emitting Heterostructures Violate Optical Reciprocity and Enable Efficient Photoluminescence in Halide-Segregated Methylammonium-Free Wide Bandgap Perovskites

Christophe Ballif, Quentin Thomas Jeangros, Peter Joseph Fiala, Chien-Jen Yang, Pietro Caprioglio, Christian Michael Wolff

This work investigates halide segregation in methylammonium-free wide bandgap perovskites by photoluminescence quantum yield (PLQY) and advanced electron microscopy techniques. Our study reveals how the formation of nano-emitting low-energy domains embedde ...

AMER CHEMICAL SOC2021

Instability of p-i-n perovskite solar cells under reverse bias

Christophe Ballif, Laura Ding, Sylvain Nicolay, Quentin Thomas Jeangros, Arnaud Walter, Florent Sahli, Peter Joseph Fiala, Chien-Jen Yang, Fan Fu, Marion Solange Madeleine Dussouillez, Ricardo Augusto Zanotto Razera, Daniel Anthony Jacobs

Partial shading can trigger permanent damage in photovoltaic modules because the illuminated solar cells drive the shaded cells into reverse bias. Under reverse bias conditions, perovskite solar cells have been shown to degrade quickly due to processes tha ...

Royal Society of Chemistry2020

I-2 vapor-induced degradation of formamidinium lead iodide based perovskite solar cells under heat-light soaking conditions

Christophe Ballif, Sylvain Nicolay, Quentin Thomas Jeangros, Adriana Paracchino, Jérémie Werner, Léo Duchêne, Peter Joseph Fiala, Fan Fu

Over the last years, the operational stability of perovskite solar cells has been significantly improved by compositional engineering, interface modification, and improved encapsulation techniques. However, irreversible degradation is still ubiquitously ob ...

2019

Complex Refractive Indices of Cesium–Formamidinium-Based Mixed-Halide Perovskites with Optical Band Gaps from 1.5 to 1.8 eV

Christophe Ballif, Sylvain Nicolay, Quentin Thomas Jeangros, Gabriel Christmann, Arnaud Walter, Jérémie Werner, Florent Sahli, Björn Niesen, Gizem Nogay, Philipp Friedrich Hermann Löper, Matthias Wolfgang Bräuninger, Peter Joseph Fiala, Chien-Jen Yang

Cesium-formamidinium-based mixed-halide perovskite materials with optical band gaps ranging from 1.5 to 1.8 eV are investigated by variable-angle spectroscopic ellipsometry. The determined complex refractive indices are shown to depend on the fabrication p ...

2018

High-Bandgap Perovskite Materials for Multijunction Solar Cells

Christophe Ballif, Quentin Thomas Jeangros, Peter Joseph Fiala, Chien-Jen Yang

2018

Hybrid sequential deposition process for fully textured perovskite/silicon tandem solar cells

Christophe Ballif, Laura Ding, Sylvain Nicolay, Quentin Thomas Jeangros, Soo-Jin Moon, Arnaud Walter, Davide Sacchetto, Mathieu Gérard Boccard, Matthieu Despeisse, Jérémie Werner, Florent Sahli, Loris Barraud, Raphaël Monnard, Monica Morales Masis, Gianluca Cattaneo, Bertrand Yves Paul Paviet-Salomon, Björn Niesen, Gizem Nogay, Oscar Esteban Rucavado Leandro, Matthias Wolfgang Bräuninger, Peter Joseph Fiala, Chien-Jen Yang, Fan Fu

Tandem solar cells that feature a high-bandgap perovskite cell on top of a lower bandgap silicon cell have the potential to reach efficiencies > 30%. Here, we present a versatile hybrid deposition method that yields conformal perovskite cells directly on t ...

IEEE2018