1. Faculty of Physics and Electronic Science, Hubei University, Wuhan, Hubei 430062, P.R. China
2. Department of Energy Technology, KTH Royal Institute of Technology, Stockholm SE-10044, Sweden
3. Clean Energy Research Lab (CERL), Department of Physics, COMSATS University Islamabad, Lahore Campus, Lahore 54000, Pakistan
4. Engineering Research Center of Nano-Geo Materials of Ministry of Education, Department of Materials Science and Chemistry, China University of Geosciences, 388 Lumo Road, Wuhan 430074, China
5. National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China