1. Beijing Advanced Innovation Center for Soft Matter Science and Engineering State Key Laboratory of Organic-Inorganic Composites Beijing University of Chemical Technology Beijing 100029 China
2. Science and Engineering Program and Texas Materials Institute The University of Texas at Austin Austin TX 78712 USA
3. College of Physics Qingdao University Qingdao 266071 China
4. Institute of Physics Chinese Academy of Sciences Beijing 100190 China