Publications by Stefaan De Wolf

Below the Urbach Edge: Solar Cell Loss Analysis Based on Full External Quantum Efficiency Spectra

Stefaan De Wolf, Jakub Holovsky, Randall Ellingson, Xin Yu Chin

We suggest a new solar cell loss analysis using theexternal quantumefficiency (EQE) measured with sufficiently high sensitivity to alsoaccount for defects. Unlike common radiative-limit methods, wherethe impact of deep defects is ignored by exponential ext ...

AMER CHEMICAL SOC2023

Photovoltaics at multi-terawatt scale: Waiting is not an option

Sophia Haussener, Stefaan De Wolf

A major renewable-energy milestone occurred in 2022: Photovoltaics (PV) exceeded a global installed capacity of 1 TWdc. But despite considerable growth and cost reduction over time, PV is still a small part of global electricity generation (4 to 5% for 202 ...

American Association for the Advancement of Science2023

Quantitative Analysis of Nanorough Hydrogenated Si(111) Surfaces through Vibrational Spectral Assignment by Periodic DFT Calculations br

Christophe Ballif, Stefaan De Wolf, Jakub Holovsky

In this work, we use periodic density functional theory(periodic DFT) to rigorously assign vibrational spectra measured on nanorough wet-processed hydrogenated Si(111) surfaces. We compare Si(111)-(1x1) surfaces etched by dilute HF and NH4F, featuring two ...

AMER CHEMICAL SOC2022

Toward Stable Monolithic Perovskite/Silicon Tandem Photovoltaics: A Six-Month Outdoor Performance Study in a Hot and Humid Climate

Christophe Ballif, Quentin Thomas Jeangros, Stefaan De Wolf, Shynggys Zhumagali

Perovskite/silicon tandem solar cells are emerging as a high-efficiency and prospectively cost-effective solar technology with great promise for deployment at the utility scale. However, despite the remarkable performance progress reported lately, assuring ...

AMER CHEMICAL SOC2021

Amorphous/Crystalline Silicon Interface Stability: Correlation between Infrared Spectroscopy and Electronic Passivation Properties

Christophe Ballif, Stefaan De Wolf, Jakub Holovsky, Silvia Martin de Nicolas Agut

Ultrathin layers of hydrogenated amorphous silicon (a-Si:H), passivating the surface of crystalline silicon (c-Si), are key enablers for high-efficiency silicon heterojunction solar cells. In this work, the authors apply highly sensitive attenuated total r ...

WILEY2020

Mitigating Plasmonic Absorption Losses at Rear Electrodes in High‐Efficiency Silicon Solar Cells Using Dopant‐Free Contact Stacks

Christophe Ballif, Quentin Thomas Jeangros, Mathieu Gérard Boccard, Stefaan De Wolf, Julie Amandine Dreon, Fan Fu, Sihua Zhong

Although charge‐carrier selectivity in conventional crystalline silicon (c‐Si) solar cells is usually realized by doping Si, the presence of dopants imposes inherent performance limitations due to parasitic absorption and carrier recombination. The develop ...

2019

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

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

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

Amorphous gallium oxide grown by low-temperature PECVD

Christophe Ballif, Aïcha Hessler-Wyser, Quentin Thomas Jeangros, Mathieu Gérard Boccard, Stefaan De Wolf, Monica Morales Masis, Eiji Kobayashi, Nathan Jacques Rodkey, Daniel Vresilovic

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