1. School of Marine Sciences/and School of Chemistry Sun Yat-Sen University, Zhuhai 519082 Guangzhou 510275 P. R. China
2. School of Electronics and Electrical Engineering Nanyang Institute of Technology Nanyang 473004 P. R. China
3. State Key Laboratory of Luminescent Materials and Devices and Institute of Optical Communication Materials South China University of Technology Guangzhou 510641 P. R. China
4. Guangdong Institute of Semiconductor Industrial Technology Guangzhou 510650 P. R. China
5. Department of Chemistry National (Taiwan) University Taipei 106 Taiwan