1. CAS Center for Excellence in Nanoscience Beijing Key Laboratory of Micro‐nano Energy and Sensor Beijing Institute of Nanoenergy and Nanosystems Chinese Academy of Sciences Beijing 101400 P. R. China
2. School of Nanoscience and Technology University of Chinese Academy of Sciences Beijing 100049 P. R. China
3. Center on Nanoenergy Research School of Physical Science and Technology Guangxi University Nanning 530004 P. R. China
4. School of Electronic Communication Technology Shenzhen Institute of Information Technology Shenzhen 518172 P. R. China
5. Shenzhen Institute for Advanced Study University of Electronic Science and Technology of China Shenzhen 518000 P. R. China
6. School of Materials Science and Engineering Georgia Institute of Technology Atlanta GA 30332‐0245 USA