1. College of Materials Science and Engineering, Guilin University of Technology, Guilin 541004, P. R. China
2. Guangxi Key Laboratory of Optical and Electronic Materials and Devices, Guilin University of Technology, Guilin 541004, P. R. China
3. Collaborative Innovation Center for Exploration of Hidden Nonferrous Metal Deposits and Development of New Materials, Guilin University of Technology, Guilin 541004, China
4. Research Center for Electronic and Optical Materials, National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044, Japan