1. Department
of Chemistry and Biochemistry, Northern Illinois University, DeKalb, Illinois 60115, United States
2. Chemistry and
Nanoscience Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
3. School of
Physics,
State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China
4. Center for Nanoscale
Materials, Argonne National Laboratory, Argonne, Illinois 60439, United States
5. Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China