1. Center on Nanoenergy Research School of Physical Science and Technology Guangxi University Nanning 530004 P. R. China
2. Beijing Institute of Nanoenergy and Nanosystems Chinese Academy of Sciences Beijing 101400 P. R. China
3. School of Nanoscience and Engineering University of Chinese Academy of Sciences Beijing 100049 P. R. China
4. School and Hospital of Stomatology Cheeloo College of Medicine Shandong University & Shandong Key Laboratory of Oral Tissue Regeneration & Shandong Engineering Laboratory for Dental Materials and Oral Tissue Regeneration & Shandong Provincial Clinical Research Center for Oral Diseases Jinan Shandong 250012 P. R. China