1. Beijing Institute of Nanoenergy and NanosystemsChinese Academy of Sciences Beijing 100083 P. R. China
2. School of Nanoscience and TechnologyUniversity of Chinese Academy of Sciences Beijing 100049 P. R. China
3. Department of Bionano TechnologyGachon University Seongnam Gyeonggi 13120 South Korea
4. School of Physics and ElectronicsCentral South University Changsha 410083 China
5. Center on Nanoenergy ResearchSchool of Physical Science and TechnologyGuangxi University Nanning 530004 China