1. Fujian Key Laboratory of Photoelectric Functional Materials; College of Materials Science and Engineering; Huaqiao University; Xiamen 361021 P. R. China
2. Department of Chemistry; Southern Methodist University; 3215 Daniel Avenue Dallas Texas 75275-0314 United States
3. Department of Chemistry; College of Chemistry and Chemical Engineering; Xiamen University; Xiamen 361005 P. R. China
4. School of Chemistry and Chemical Engineering; Shandong University; Jinan 250100 P. R. China
5. School of Materials Science and Engineering; Nanyang Technological University; Singapore 639798 Singapore
6. Key Laboratory of Flexible Electronics & Institute of Advanced Materials; Jiangsu National Synergetic Innovation Center for Advanced Materials; Nanjing Tech. University; 30 South Puzhu Road Nanjing 211816 P. R. China