1. Center
for Nanotechnology and Molecular Materials, Department of Physics, Wake Forest University, Winston-Salem, North Carolina 27109, United States
2. SZU-NUS Collaborative Innovation Center for Optoelectronic Science & Technology, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
3. Chemistry
Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87544, United States
4. Dalian
Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China