1. Wright Center for Photovoltaics Innovation and Commercialization School for Solar and Advanced Renewable Energy Department of Physics and Astronomy University of Toledo Toledo Ohio 43606 United States
2. Adolphe Merkle Institute Chemin des Verdiers 4 CH‐1700 Fribourg Switzerland
3. École Polytechnique Fédérale de Lausanne Station 6 CH‐1015 Lausanne Switzerland