1. Department of Materials Science and Engineering and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
2. Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
3. Department of Civil and Environmental Engineering and Department of Mechanical Engineering, Center for Engineering and Health, and Skin Disease Research Center, Northwestern University, Evanston, IL 60208, USA.
4. Department of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, P.R. China.
5. Department of Materials Science and Engineering, Department of Energy Engineering, Hanyang University, Seoul 133-791, Republic of Korea.
6. Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
7. Key Laboratory of Pressure Systems and Safety (MOE), School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, P.R. China.
8. Center for Mechanics and Materials, Tsinghua University, Beijing 100084, P.R. China.
9. Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.