1. Institute of Polymer Optoelectronic Materials and DevicesState Key Laboratory of Luminescent Materials and DevicesSouth China University of Technology Guangzhou 510640 P. R. China
2. State Key Laboratory for Mechanical Behavior of MaterialsXi'an Jiaotong University Xi'an 710049 P. R. China
3. Department of ChemistryHong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong