1. School of Physical Science and TechnologyShanghaiTech University Shanghai 201210 P. R. China
2. School of Chemistry and Chemical EngineeringUniversity of Chinese Academy of Science Beijing 100049 P. R. China
3. Shanghai Institute of CeramicsChinese Academy of Science Shanghai 200050 P. R. China
4. Department of Electrical and Computer EngineeringUniversity of Toronto Toronto Ontario M5S 3G4 Canada
5. Shenzhen Key Laboratory of NanobiomechanicsShenzhen Institutes of Advanced TechnologyChinese Academy of Sciences Shenzhen 518055 Guangdong P. R. China
6. College of ChemistryKey Laboratory of Theoretical & Computational Photochemistry of Ministry of EducationBeijing Normal University Beijing 100875 P. R. China
7. Department of Mechanical EngineeringUniversity of Washington Seattle WA 98195‐2600 USA