1. Institute of Materials, China Academy of Engineering Physics No. 9, Huafengxincun, Jiangyou, Sichuan 621908, P. R. China
2. Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province, Shantou University, Shantou, Guangdong 515063, P. R. China
3. ISM, UMR CNRS N° 5255, Université de Bordeaux, 33405 Talence Cedex, France