Publications by Philipp Friedrich Hermann Löper

Nanoscale Study of the Hole-Selective Passivating Contacts with High Thermal Budget Using C-AFM Tomography

Christophe Ballif, Quentin Thomas Jeangros, Franz-Josef Haug, Gizem Nogay, Martin Ledinsky, Philipp Friedrich Hermann Löper

We investigate hole-selective passivating contacts that consist of an interfacial layer of silicon oxide (SiOx) and a layer of boron-doped SiCx(p). The fabrication process of these contacts involves an annealing step at temperatures above 750 degrees C whi ...

AMER CHEMICAL SOC2021

Numerical simulations of hole carrier selective contacts in p-type c-Si solar cells

Christophe Ballif, Philipp Friedrich Hermann Löper, Andrea Ingenito

This work presents a systematic analysis of the transport mechanism and surface passivation of tunneling oxide (SiO2)/p-type poly-silicon (poly-Si(p)) junctions applied to p-type crystalline silicon (c-Si) solar cells by means of TCAD numerical simulations ...

ELSEVIER2019

Phosphorous-Doped Silicon Carbide as Front-Side Full-Area Passivating Contact for Double-Side Contacted c-Si Solar Cells

Christophe Ballif, Philippe Wyss, Franz-Josef Haug, Matthieu Despeisse, Gizem Nogay, Philipp Friedrich Hermann Löper, Josua Andreas Stückelberger, Andrea Ingenito, Luca Gnocchi

We present an electron selective passivating contact based on a tunneling SiOx capped with a phosphorous doped siliconcarbideandpreparedwithahigh-temperaturethermalanneal. We investigate in detail the effects of the preparation conditions of theSiCx(n)(i.e ...

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

Toward Annealing-Stable Molybdenum-Oxide-Based Hole-Selective Contacts For Silicon Photovoltaics

Christophe Ballif, Stefaan De Wolf, Mathieu Gérard Boccard, Jérémie Werner, Jonas Geissbühler, Monica Morales Masis, Philipp Friedrich Hermann Löper, Oscar Esteban Rucavado Leandro, Stephanie Essig, Julie Amandine Dreon

Molybdenum oxide (MoOX) combines a high work function with broadband optical transparency. Sandwiched between a hydrogenated intrinsic amorphous silicon passivation layer and a transparent conductive oxide, this material allows a highly efficient hole‐sele ...

2018

Silicon heterojunction solar cells and methods of manufacture

Christophe Ballif, Gizem Nogay, Philipp Friedrich Hermann Löper, Andrea Ingenito

The present invention relates to a solar cell comprising a heterojunction photoelectric device comprising, a front electrode layer, a back electrode layer comprising a metallic contact layer (300), a light-absorbing silicon layer (1 ) arranged between said ...

2018

Carrier injection from amorphous silicon into crystalline silicon determined with photoluminescence

Gizem Nogay, Philipp Friedrich Hermann Löper, Andrea Ingenito

Intrinsic amorphous silicon provides excellent surface passivation on crystalline silicon. It has previously been shown, that carriers that are photo generated in the amorphous silicon can be efficiently electronically injected into the crystalline silicon ...

IEEE2018

Recombination Analysis of Phosphorus-Doped Nanostructured Silicon Oxide Passivating Electron Contacts for Silicon Solar Cells

Christophe Ballif, Philippe Wyss, Franz-Josef Haug, Matthieu Despeisse, Gizem Nogay, Philipp Friedrich Hermann Löper, Josua Andreas Stückelberger, Andrea Ingenito

2018

Charge carrier transport mechanisms of passivating contacts studied by temperature-dependent J-V measurements

Gizem Nogay, Philipp Friedrich Hermann Löper

2018

Hole-Collection Mechanism in Passivating Metal-Oxide Contacts on Si Solar Cells: Insights From Numerical Simulations

Christophe Ballif, Stefaan De Wolf, Philipp Friedrich Hermann Löper, Stephanie Essig

2018

Properties of mixed phase silicon-oxide-based passivating contacts for silicon solar cells

Christophe Ballif, Quentin Thomas Jeangros, Philippe Wyss, Franz-Josef Haug, Matthieu Despeisse, Iris Anita Mack, Gizem Nogay, Philipp Friedrich Hermann Löper, Josua Andreas Stückelberger, Andrea Ingenito

2018

A passivating contact for silicon solar cells formed during a single firing thermal annealing

Christophe Ballif, Quentin Thomas Jeangros, Franz-Josef Haug, Matthieu Despeisse, Monica Morales Masis, Gizem Nogay, Philipp Friedrich Hermann Löper, Oscar Esteban Rucavado Leandro, Andrea Ingenito

Passivating contacts are indispensable for achieving high conversion efficiency in crystalline-silicon solar cells. Their realization and integration into a convenient process flow have become crucial research objectives. Here, we report an alternative pas ...

2018

Measuring carrier injection from amorphous silicon into crystalline silicon using photoluminescence

Gizem Nogay, Philipp Friedrich Hermann Löper

In devices with intrinsic amorphous silicon layer on a crystalline silicon substrate, the light absorbed in the amorphous layer can be weakly electronically coupled into the silicon base. Such carrier injection has previously been reported from measurement ...

WILEY2018

Crystalline Silicon Solar Cells With Coannealed Electron- and Hole-Selective SiCx Passivating Contacts

Christophe Ballif, Quentin Thomas Jeangros, Philippe Wyss, Franz-Josef Haug, Monica Morales Masis, Gizem Nogay, Philipp Friedrich Hermann Löper, Josua Andreas Stückelberger, Oscar Esteban Rucavado Leandro, Andrea Ingenito

We present electron- and hole-selective passivating contacts based on wet-chemically grown interfacial SiOx and overlying in-situ doped silicon carbide (SiCx) deposited by plasma-enhanced chemical vapor deposition. After annealing at 850 degrees C, excelle ...

2018

Numerical Simulation of Temperature Dependence of MoOx Based SHJ Solar Cell

Christophe Ballif, Philipp Friedrich Hermann Löper, Stephanie Essig

Transition metal oxides based high efficiency silicon heterojunction (SHJ) solar cells have emerged as promising candidate due to their low manufacturing cost and avoidance of poisonous dopant gases. Temperature dependent J V curves in such solar cells cou ...

AMER INST PHYSICS2018

Impact Impact of different capping layers on carrier injection efficiency between amorphous and crystalline silicon measured using photoluminescence

Gizem Nogay, Philipp Friedrich Hermann Löper, Andrea Ingenito

Intrinsic amorphous silicon provides excellent surface passivation on crystalline silicon. It has previously been shown, that carriers that are photo generated in the amorphous silicon can be efficiently electronically injected into the crystalline silicon ...

ELSEVIER SCIENCE BV2018

Interplay of annealing temperature and doping in hole selective rear contacts based on silicon-rich silicon-carbide thin films

Christophe Ballif, Philippe Wyss, Franz-Josef Haug, Matthieu Despeisse, Monica Morales Masis, Gizem Nogay, Philipp Friedrich Hermann Löper, Josua Andreas Stückelberger, Oscar Esteban Rucavado Leandro

We present a detailed optimization of a hole selective rear contact for p-type crystalline silicon solar cells which relies on full-area processes and provides full-area passivation. The passivating hole-contact is based on a layer stack comprising a chemi ...

Elsevier Science Bv2017

Solar photovoltaic module

Christophe Ballif, Philippe Wyss, Franz-Josef Haug, Philipp Friedrich Hermann Löper, Josua Andreas Stückelberger

In the present invention a new solar photovoltaic module is proposed comprising a solar cell comprising a silicon layer having a first (1 a) surface and a second surface (1a) opposite to said first surface. The solar cell further comprises a passivating la ...

2017

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

Passivating electron contact based on highly crystalline nanostructured silicon oxide layers for silicon solar cells

Christophe Ballif, Quentin Thomas Jeangros, Philippe Wyss, Xavier Niquille, Franz-Josef Haug, Matthieu Despeisse, Gizem Nogay, Martin Ledinsky, Philipp Friedrich Hermann Löper, Josua Andreas Stückelberger

We present a novel passivating contact structure based on a nanostructured silicon-based layer. Traditional poly-Si junctions feature excellent junction characteristics but their optical absorption induces current losses when applied to the solar cell fron ...

Elsevier Science Bv2016