1. School
of Optical and Electronic Information, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei 430074, China
2. Chemical
and Materials Sciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
3. Shenzhen R & D Center of Huazhong University of Science and Technology, Shenzhen, Guangdong 518057, China