1. Center on Nanoenergy Research, School of Physical Science and Technology Guangxi University Nanning 530004 P. R. China
2. Beijing Institute of Nanoenergy and Nanosystems Chinese Academy of Sciences Beijing 101400 P. R. China
3. State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering Donghua University Shanghai 201620 P. R. China
4. Georgia Institute of Technology Atlanta Georgia 30332‐0245 USA
5. Shandong Zhongke Naneng Energy Technology Co., Ltd. Dongying 257061 P. R. China