1. Department of Chemistry, University of Idaho, Moscow, Idaho 83844-2343, United States
2. Research Centre of Flexible Printed Electronic Technology, Harbin Institute of Technology, Shenzhen 518055, China
3. Zhuhai Institute of Advanced Technology Chinese Academy of Sciences, Biomaterials Research Center, Zhuhai 519003, China
4. Department of Physics, Naval Postgraduate School, Monterey, California 93943, United States