1. College of Science, Institute of Materials Physics and Chemistry, Nanjing Forestry University, Nanjing 210037, P. R. China
2. Institute of Physics and Technology, Ural Federal University, Mira Str. 19, 620002 Yekaterinburg, Russia
3. Department of Physical and Chemical Sciences, University of L’Aquila, via Vetoio, 67100 L’Aquila (AQ), Italy
4. College of Chemistry and Chemical Engineering, Qingdao University, Qingdao 266071, P. R. China
5. National Institute of Materials Physics, Atomistilor 405A, 077125 Magurele, Romania
6. Department of Physics, National Cheng Kung University, 1 Ta-Hsueh Road, 70101 Tainan, Taiwan
7. Department of Information Engineering, Infrastructures and Sustainable Energy (DIIES), University “Mediterranea” of Reggio Calabria, Loc. Feo di Vito, 89122 Reggio Calabria, Italy
8. CNR-IOM, TASC Laboratory, Area Science Park-Basovizza, 34139 Trieste, Italy