1. Beijing Key Laboratory of Novel Thin-Film Solar Cells
2. North China Electric Power University
3. Beijing
4. P. R. China
5. Key Laboratory of Novel Thin Film Solar Cells
6. Beijing National Laboratory for Condensed Matter Physics and Institute of Physics
7. Chinese Academy of Sciences
8. Beijing 100190
9. China
10. School of Physics
11. Institute of Applied Technology
12. Hefei Institutes of Physical Science
13. Hefei 230031