Publications by Björn Niesen | EPFL Graph Search

Vapor Transport Deposition of Methylammonium Iodide for Perovskite Solar Cells

Christophe Ballif, Quentin Thomas Jeangros, Florent Sahli, Cédric Bucher, Björn Niesen, Léo Duchêne, Quentin Jean-Marie Armand Guesnay, Aymeric Michel Schafflützel, Nathanaël Miaz, 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, Björn Niesen, Michael Elias Stückelberger, Jérémie Werner, Yun Luo, 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

Wolfgang Richard Tress, Simone Meloni, Zaiwei Wang, Björn Niesen, Juan-Pablo Correa-Baena, Chien-Jen Yang, Mozhgan Yavari, 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, Jérémie Werner, Quentin Thomas Jeangros, Florent Sahli, Arnaud Walter, Sylvain Nicolay, 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, Florent Sahli, Quentin Thomas Jeangros, Matthias Wolfgang Bräuninger, Davide Sacchetto, Bertrand Yves Paul Paviet-Salomon, Gianluca Cattaneo, Matthieu Despeisse, Mathieu Gérard Boccard, Sylvain Nicolay

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, Jérémie Werner, Quentin Thomas Jeangros, Matthias Wolfgang Bräuninger, Gabriel Christmann, Florent Sahli, Arnaud Walter, Sylvain Nicolay, Björn Niesen, Gizem Nogay

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, Olivier Denis Dupré, Stefaan De Wolf, Björn Niesen

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, Quentin Thomas Jeangros, Davide Sacchetto, Bertrand Yves Paul Paviet-Salomon, Florent Sahli, Arnaud Walter, Gianluca Cattaneo, Matthieu Despeisse, Mathieu Gérard Boccard, Sylvain Nicolay

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, Beat Ruhstaller, Björn Niesen, Jérémie Werner

2018