1. Institute for Clean Energy and Advanced MaterialsSchool of Materials and EnergySouthwest University Chongqing 400715 P. R. China
2. Electronic & Magnetic Materials DepartmentAdvanced Materials DivisionCentral Metallurgical Research and Development Institute (CMRDI) Helwan, P.O. Box 87 Cairo 11421 Egypt
3. College of Physics and Electronics EngineeringChongqing Normal University Chongqing 401331 P. R. China
4. Department of ChemistryUniversity of Pavia Viale Taramelli 14 27100 Pavia Italy