1. CAS Key Laboratory of Design and Assembly of Functional Nanostructures, and Fujian Provincial Key Laboratory of Nanomaterials Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences Fuzhou Fujian 35002 P. R China
2. Fujian Normal University Fuzhou 350007 P. R. China
3. Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China Fuzhou Fujian 350108 P. R. China
4. Natural Sciences and Science Education National Institute of Education Nanyang Technological University 637616 Singapore
5. NUS High School of Math and Science 129957 Singapore