1. Key Laboratory of Photovoltaic and Energy Conservation Materials CAS Institute of Solid State Physics Hefei Institutes of Physical Science Chinese Academy of Sciences Hefei 230031 China
2. Department of Materials Science and Engineering University of Washington Seattle WA 98195 USA
3. Shandong Provincial Key Laboratory/Collaborative Innovation Center of Chemical Energy Storage & Novel Cell Technology School of Chemistry and Chemical Engineering Liaocheng University Liaocheng 252000 China
4. College of Physics, Mechanical and Electronical College Shijiazhuang University Shijiazhuang 050035 China
5. College of Science Hebei University of Science and Technology Shijiazhuang 050018 China
6. College of Physics, Mechanical and Electronical College Shijiazhuang University Shijiazhuang 050035 P. R. China