1. Laboratory of Renewable Energy (LMER), Institute of Chemical Sciences and Engineering (ISIC), Basic Science Faculty (SB), École Polytechnique Fédérale de Lausanne (EPFL) Valais/Wallis, Energypolis, Rue de l’Industrie 17, Sion CH-1951, Switzerland
2. Empa Materials Science and Technology, Dübendorf CH-8600, Switzerland
3. Interdisciplinary Centre for Electron Microscopy (CIME), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland