1. Department of Physics, Anhui Normal University, Wuhu, Anhui, 241000, People’s Republic of China, Department of Chemistry, Fuzhou University, Fuzhou, Fujian, 350002, People’s Republic of China, and Dipartimento di Scienza dei Materiali and CNISM, Università degli Studi di Milano-Bicocca, via Cozzi 53, 20125 Milano, Italy