1. Ultrafast Laser Laboratory, Key Laboratory of Opto-electronic Information Science and Technology of Ministry of Education, College of Precision Instruments and Opto-electronics Engineering, Tianjin University, Tianjin 300072, China
2. Institute of Molecular Plus, Tianjin University, Tianjin 300072, P. R. China
3. Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
4. Institute of Materials Research and Engineering, Singapore 138634