1. Department of Electrical and Information Engineering, Polytechnic University of Bari, Via E. Orabona 4, 70125 Bari, Italy
2. State Key Laboratory of Organic–Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, P. R. China
3. School of Chemistry, University of New South Wales, 2033 Sydney, Australia
4. Institute of Chemistry, Rheinische Friedrich-Wilhelms-Universität Bonn, 53113 Bonn, Germany
5. Department of Physics, University of Warwick, Coventry CV4 7AL, UK
6. Department of Mechanics, Mathematics and Management, Polytechnic University of Bari, Via E. Orabona 4, 70125 Bari, Italy