1. AGH University of Science and Technology
2. Faculty of Energy and Fuels
3. 30-059 Krakow
4. Poland
5. AGH Centre of Energy
6. University of Science and Technology Beijing
7. School of Materials Science and Engineering
8. Beijing 100083
9. China
10. Beijing Municipal Key Lab for Advanced Energy Materials and Technologies
11. Academic Centre for Materials and Nanotechnology
12. Department of Physics
13. Northern Illinois University
14. DeKalb
15. USA
16. Institute of Physics
17. Polish Academy of Sciences
18. 02668 Warsaw