Publications by Björn Niesen | EPFL Graph Search

Vapor Transport Deposition of Methylammonium Iodide for Perovskite Solar Cells

Christophe Ballif, Quentin Thomas Jeangros, Cédric Bucher, Florent Sahli, Léo Duchêne, Björn Niesen, Aymeric Michel Schafflützel, Nathanaël Miaz, Quentin Jean-Marie Armand Guesnay, Niccolo Salsi

Vapor-based processes are promising options to deposit metal halide perovskite solar cells in an industrial environment due to their ability to deposit uniform layers over large areas in a controlled environment without resorting to the use of (possibly to ...

2021

Effects of X-rays on Perovskite Solar Cells

Christophe Ballif, Yun Luo, Michael Elias Stückelberger, Jérémie Werner, Björn Niesen, Xueying Li

Synchrotron micro- and nanoprobe beamlines have demonstrated great potential to advance photovoltaic devices. Most importantly, their small X-ray spot size has enabled the direct correlation of electrical performance with elemental composition at subgrain ...

AMER CHEMICAL SOC2020

How far does the defect tolerance of lead-halide perovskites range? The example of Bi impurities introducing efficient recombination centers

Björn Niesen, Simone Meloni, Wolfgang Richard Tress, Juan-Pablo Correa-Baena, Zaiwei Wang, Mozhgan Yavari, Chien-Jen Yang, Firouzeh Ebadi Garjan

One of the key properties of lead-halide perovskites employed in solar cells is the defect tolerance of the materials, in particular regarding intrinsic point defects, which mainly form shallow traps. Considering that high luminescence yields and photovolt ...

Royal Society of Chemistry2019

Multiple Charge Transfer States in Donor-Acceptor Heterojunctions with Large Frontier Orbital Energy Offsets

Xiao Liu, Björn Niesen, Chien-Jen Yang

In this work, we demonstrate several organic amorphous donor-acceptor systems that exhibit sub-bandgap features over a more than 2 eV spectral range. An in-depth study of one of these systems, NPB:HAT-CN (NPB is N,N'-di(1-naphthyl)-N,N'-diphenyl-(1,1'-biph ...

2019

Perovskite/Perovskite/Silicon Monolithic Triple-Junction Solar Cells with a Fully Textured Design

Christophe Ballif, Sylvain Nicolay, Quentin Thomas Jeangros, Arnaud Walter, Jérémie Werner, Florent Sahli, Björn Niesen, Fan Fu

High efficiency triple-junction solar cells are currently made of III−V semiconductors using expensive deposition methods. Perovskite/perovskite/silicon monolithic triple-junction solar cells could be a lower-cost alternative as no epitaxial growth is requ ...

2018

Fully textured monolithic perovskite/silicon tandem solar cells with 25.2% power conversion efficiency

Christophe Ballif, Laura Ding, Sylvain Nicolay, Quentin Thomas Jeangros, Davide Sacchetto, Mathieu Gérard Boccard, Matthieu Despeisse, Jérémie Werner, Florent Sahli, Loris Barraud, Raphaël Monnard, Gianluca Cattaneo, Bertrand Yves Paul Paviet-Salomon, Björn Niesen, Matthias Wolfgang Bräuninger

Tandem devices combining perovskite and silicon solar cells are promising candidates to achieve power conversion efficiencies above 30% at reasonable costs. State-of-the-art monolithic two-terminal perovskite/silicon tandem devices have so far featured sil ...

2018

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

Field Performance versus Standard Test Condition Efficiency of Tandem Solar Cells and the Singular Case of Perovskites/Silicon Devices

Christophe Ballif, Stefaan De Wolf, Björn Niesen, Olivier Denis Dupré

Multijunction cells may offer a cost-effective route to boost the efficiency of industrial photovoltaics. For any technology to be deployed in the field, its performance under actual operating conditions is extremely important. In this perspective, we eval ...

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

Design of perovskite/crystalline-silicon monolithic tandem solar cells

Christophe Ballif, Jérémie Werner, Beat Ruhstaller, Björn Niesen

2018

Interpretation and evolution of open-circuit voltage, recombination, ideality factor and subgap defect states during reversible light-soaking and irreversible degradation of perovskite solar cells

Michael Graetzel, Konrad Domanski, Björn Niesen, Wolfgang Richard Tress, Pankaj Kumar Yadav, Mozhgan Yavari

2018

Correction: Interpretation and evolution of open-circuit voltage, recombination, ideality factor and subgap defect states during reversible light-soaking and irreversible degradation of perovskite solar cells (vol 11, pg 151, 2018)

Michael Graetzel, Konrad Domanski, Björn Niesen, Wolfgang Richard Tress, Pankaj Kumar Yadav, Mozhgan Yavari

2018

Charge Collection in Hybrid Perovskite Solar Cells: Relation to the Nanoscale Elemental Distribution

Christophe Ballif, Michael Elias Stückelberger, Jérémie Werner, Björn Niesen

Unveiling the correlation between elemental composition, Fermi-level splitting, and charge collection in perovskite solar cells (PSCs) when exposed to different environments is crucial to understanding the origin of defects. This will enable defect enginee ...

Ieee-Inst Electrical Electronics Engineers Inc2017

Improved Optics in Monolithic Perovskite/Silicon Tandem Solar Cells with a Nanocrystalline Silicon Recombination Junction

Christophe Ballif, Aïcha Hessler-Wyser, Sylvain Nicolay, Quentin Thomas Jeangros, Stefaan De Wolf, Matthieu Despeisse, Jérémie Werner, Florent Sahli, Loris Barraud, Raphaël Monnard, Johannes Peter Seif, Andrea Tomasi, Bertrand Yves Paul Paviet-Salomon, Björn Niesen, Matthias Wolfgang Bräuninger

Perovskite/silicon tandem solar cells are increasingly recognized as promi-sing candidates for next-generation photovoltaics with performance beyond the single-junction limit at potentially low production costs. Current designs for monolithic tandems rely ...

2017

Impact of organic overlayers on a-Si:H/c-Si surface potential

Christophe Ballif, Stefaan De Wolf, Johannes Peter Seif, Andrea Tomasi, Björn Niesen

Bilayers of intrinsic and doped hydrogenated amorphous silicon, deposited on crystalline silicon (c-Si) surfaces, simultaneously provide contact passivation and carrier collection in silicon heterojunction solar cells. Recently, we have shown that the pres ...

American Institute of Physics2017

The Role of Water in the Reversible Optoelectronic Degradation of Hybrid Perovskites at Low Pressure

Christophe Ballif, Michael Elias Stückelberger, Jérémie Werner, Björn Niesen

There is no doubt about the potential offered by the low-cost fabrication and high efficiency of hybrid organic inorganic perovskite solar cells. However, the service lifetimes of these devices must be increased from months to years to capitalize on their ...

American Chemical Society2017

Spectrally resolved nonlinearity and temperature dependence of perovskite solar cells

Christophe Ballif, Jérémie Werner, Florent Sahli, Björn Niesen, Matthias Wolfgang Bräuninger

An accurate electrical device characterization of hybrid organic-inorganic halide perovskite solar cells (PSCs) is an important prerequisite for further improvement and industrial transfer of this promising photovoltaic technology. In this work, we study t ...

Elsevier2017

Efficient Monolithic Perovskite/Perovskite Tandem Solar Cells

Christophe Ballif, Jérémie Werner, Björn Niesen

Efficient monolithic perovskite/perovskite tandem solar cells are fabricated using two perovskite absorbers with complementary bandgaps. By employing doped organic semiconductors, an efficient and selective extraction of the charge carriers is ensured. Thi ...

Wiley-VCH Verlag Berlin2017

Photocurrent Spectroscopy of Perovskite Layers and Solar Cells: A Sensitive Probe of Material Degradation

Christophe Ballif, Stefaan De Wolf, Jérémie Werner, Jakub Holovsky, Björn Niesen, Martin Ledinsky, Philipp Friedrich Hermann Löper, Martin Müller

Optical absorptance spectroscopy of polycrystalline CH3NH3PbI3 films usually indicates the presence of a PbI2 phase, either as a preparation residue or due to film degradation, but gives no insight on how this may affect electrical properties. Here, we app ...

Amer Chemical Soc2017

Perovskite/silicon tandem solar cells: marriage of convenience or true love story? - An overview

Christophe Ballif, Jérémie Werner, Björn Niesen

Perovskite/silicon tandem solar cells have reached efﬁciencies above 25% in just about three years of development, mostly driven by the rapid progress made in the perovskite solar cell research ﬁeld. This review aims to give an overview of the achievements ...

2017