1. State Key Laboratory of Alternate Electrical Power System with Renewable Energy SourcesNorth China Electric Power University Beijing 102206 P. R. China
2. Key Laboratory of Photovoltaic and Energy Conservation MaterialsInstitute of Applied TechnologyHefei Institutes of Physical ScienceChinese Academy of Sciences Hefei 230031 Anhui P. R. China
3. Fujian Provincial Key Laboratory of Photoelectric Functional MaterialsInstitute of Materials Physical ChemistryHuaqiao University Xiamen 361021 P. R. China
4. Group for Molecular Engineering of Functional MaterialsInstitute of Chemical Sciences and EngineeringÉcole Polytechnique Fédérale de Lausanne CH‐1951 Sion Switzerland