1. State Key Laboratory of Alternate Electrical Power System with Renewable Energy SourcesNorth China Electric Power University Beijing 102206 China
2. Beijing Key Laboratory of Novel Thin‐Film Solar CellsBeijing Key Laboratory of Energy Safety and Clean UtilizationNorth China Electric Power University Beijing 102206 China
3. Institute of Materials Science & EngineeringUniversity of Washington Seattle 98195 USA
4. Group for Molecular Engineering of Functional Materials Institute of Chemical Sciences and Engineering École Polytechnique Fédérale de Lausanne (EPFL) CH‐1951 Sion Switzerland